Articles | Volume 13, issue 5
Atmos. Chem. Phys., 13, 2607–2634, 2013
© Author(s) 2013. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Research article 05 Mar 2013
Research article | 05 Mar 2013
Evaluation of preindustrial to present-day black carbon and its albedo forcing from Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP)
Y. H. Lee et al.
G. W. Mann, K. S. Carslaw, C. L. Reddington, K. J. Pringle, M. Schulz, A. Asmi, D. V. Spracklen, D. A. Ridley, M. T. Woodhouse, L. A. Lee, K. Zhang, S. J. Ghan, R. C. Easter, X. Liu, P. Stier, Y. H. Lee, P. J. Adams, H. Tost, J. Lelieveld, S. E. Bauer, K. Tsigaridis, T. P. C. van Noije, A. Strunk, E. Vignati, N. Bellouin, M. Dalvi, C. E. Johnson, T. Bergman, H. Kokkola, K. von Salzen, F. Yu, G. Luo, A. Petzold, J. Heintzenberg, A. Clarke, J. A. Ogren, J. Gras, U. Baltensperger, U. Kaminski, S. G. Jennings, C. D. O'Dowd, R. M. Harrison, D. C. S. Beddows, M. Kulmala, Y. Viisanen, V. Ulevicius, N. Mihalopoulos, V. Zdimal, M. Fiebig, H.-C. Hansson, E. Swietlicki, and J. S. Henzing
Atmos. Chem. Phys., 14, 4679–4713,
D. T. Shindell, J.-F. Lamarque, M. Schulz, M. Flanner, C. Jiao, M. Chin, P. J. Young, Y. H. Lee, L. Rotstayn, N. Mahowald, G. Milly, G. Faluvegi, Y. Balkanski, W. J. Collins, A. J. Conley, S. Dalsoren, R. Easter, S. Ghan, L. Horowitz, X. Liu, G. Myhre, T. Nagashima, V. Naik, S. T. Rumbold, R. Skeie, K. Sudo, S. Szopa, T. Takemura, A. Voulgarakis, J.-H. Yoon, and F. Lo
Atmos. Chem. Phys., 13, 2939–2974,
Peter M. Abbott, Gill Plunkett, Christophe Corona, Nathan J. Chellman, Joseph R. McConnell, John R. Pilcher, Markus Stoffel, and Michael Sigl
Clim. Past, 17, 565–585,Short summary
Volcanic eruptions are a key source of climatic variability, and greater understanding of their past influence will increase the accuracy of future projections. We use volcanic ash from a 1477 CE Icelandic eruption in a Greenlandic ice core as a temporal fix point to constrain the timing of two eruptions in the 1450s CE and their climatic impact. Despite being the most explosive Icelandic eruption in the last 1200 years, the 1477 CE event had a limited impact on Northern Hemisphere climate.
Margot Clyne, Jean-Francois Lamarque, Michael J. Mills, Myriam Khodri, William Ball, Slimane Bekki, Sandip S. Dhomse, Nicolas Lebas, Graham Mann, Lauren Marshall, Ulrike Niemeier, Virginie Poulain, Alan Robock, Eugene Rozanov, Anja Schmidt, Andrea Stenke, Timofei Sukhodolov, Claudia Timmreck, Matthew Toohey, Fiona Tummon, Davide Zanchettin, Yunqian Zhu, and Owen B. Toon
Atmos. Chem. Phys., 21, 3317–3343,Short summary
This study finds how and why five state-of-the-art global climate models with interactive stratospheric aerosols differ when simulating the aftermath of large volcanic injections as part of the Model Intercomparison Project on the climatic response to Volcanic forcing (VolMIP). We identify and explain the consequences of significant disparities in the underlying physics and chemistry currently in some of the models, which are problems likely not unique to the models participating in this study.
Claudia Tebaldi, Kevin Debeire, Veronika Eyring, Erich Fischer, John Fyfe, Pierre Friedlingstein, Reto Knutti, Jason Lowe, Brian O'Neill, Benjamin Sanderson, Detlef van Vuuren, Keywan Riahi, Malte Meinshausen, Zebedee Nicholls, Katarzyna B. Tokarska, George Hurtt, Elmar Kriegler, Jean-Francois Lamarque, Gerald Meehl, Richard Moss, Susanne E. Bauer, Olivier Boucher, Victor Brovkin, Young-Hwa Byun, Martin Dix, Silvio Gualdi, Huan Guo, Jasmin G. John, Slava Kharin, YoungHo Kim, Tsuyoshi Koshiro, Libin Ma, Dirk Olivié, Swapna Panickal, Fangli Qiao, Xinyao Rong, Nan Rosenbloom, Martin Schupfner, Roland Séférian, Alistair Sellar, Tido Semmler, Xiaoying Shi, Zhenya Song, Christian Steger, Ronald Stouffer, Neil Swart, Kaoru Tachiiri, Qi Tang, Hiroaki Tatebe, Aurore Voldoire, Evgeny Volodin, Klaus Wyser, Xiaoge Xin, Shuting Yang, Yongqiang Yu, and Tilo Ziehn
Earth Syst. Dynam., 12, 253–293,Short summary
We present an overview of CMIP6 ScenarioMIP outcomes from up to 38 participating ESMs according to the new SSP-based scenarios. Average temperature and precipitation projections according to a wide range of forcings, spanning a wider range than the CMIP5 projections, are documented as global averages and geographic patterns. Times of crossing various warming levels are computed, together with benefits of mitigation for selected pairs of scenarios. Comparisons with CMIP5 are also discussed.
Maria Sand, Bjørn H. Samset, Gunnar Myhre, Jonas Gliß, Susanne E. Bauer, Huisheng Bian, Mian Chin, Ramiro Checa-Garcia, Paul Ginoux, Zak Kipling, Alf Kirkevåg, Harri Kokkola, Philippe Le Sager, Marianne T. Lund, Hitoshi Matsui, Twan van Noije, Samuel Remy, Michael Schulz, Philip Stier, Camilla W. Stjern, Toshihiko Takemura, Kostas Tsigaridis, Svetlana G. Tsyro, and Duncan Watson-Parris
Atmos. Chem. Phys. Discuss.,
Preprint under review for ACPShort summary
Absorption of shortwave radiation by aerosols can modify precipitation and clouds, but are poorly constrained in models. 15 different aerosol models from AeroCom Phase III have reported total aerosol absorption and for the first time 10 these models have reported in a consistent experiment the contributions to absorption from black carbon, dust and organic aerosol. Here, we document the model diversity in aerosol absorption and compare with observations.
Gillian Thornhill, William Collins, Dirk Olivié, Ragnhild B. Skeie, Alex Archibald, Susanne Bauer, Ramiro Checa-Garcia, Stephanie Fiedler, Gerd Folberth, Ada Gjermundsen, Larry Horowitz, Jean-Francois Lamarque, Martine Michou, Jane Mulcahy, Pierre Nabat, Vaishali Naik, Fiona M. O'Connor, Fabien Paulot, Michael Schulz, Catherine E. Scott, Roland Séférian, Chris Smith, Toshihiko Takemura, Simone Tilmes, Kostas Tsigaridis, and James Weber
Atmos. Chem. Phys., 21, 1105–1126,Short summary
We find that increased temperatures affect aerosols and reactive gases by changing natural emissions and their rates of removal from the atmosphere. Changing the composition of these species in the atmosphere affects the radiative budget of the climate system and therefore amplifies or dampens the climate response of climate models of the Earth system. This study found that the largest effect is a dampening of climate change as warmer temperatures increase the emissions of cooling aerosols.
Huikun Liu, Qiyuan Wang, Li Xing, Yong Zhang, Ting Zhang, Weikang Ran, and Junji Cao
Atmos. Chem. Phys., 21, 973–987,Short summary
We conducted black carbon (BC) source apportionment on the southeastern Tibetan Plateau (TP) by an improved aethalometer model with the site-dependent Ångström exponent and BC mass absorption cross section (MAC). The result shows that the biomass-burning BC on the TP is slightly higher than fossil fuel BC, mainly from cross-border transportation instead of the local region, and the BC radiative effect is lower than that in the southwestern Himalaya but higher than that on the northeastern TP.
Gillian D. Thornhill, William J. Collins, Ryan J. Kramer, Dirk Olivié, Ragnhild B. Skeie, Fiona M. O'Connor, Nathan Luke Abraham, Ramiro Checa-Garcia, Susanne E. Bauer, Makoto Deushi, Louisa K. Emmons, Piers M. Forster, Larry W. Horowitz, Ben Johnson, James Keeble, Jean-Francois Lamarque, Martine Michou, Michael J. Mills, Jane P. Mulcahy, Gunnar Myhre, Pierre Nabat, Vaishali Naik, Naga Oshima, Michael Schulz, Christopher J. Smith, Toshihiko Takemura, Simone Tilmes, Tongwen Wu, Guang Zeng, and Jie Zhang
Atmos. Chem. Phys., 21, 853–874,Short summary
This paper is a study of how different constituents in the atmosphere, such as aerosols and gases like methane and ozone, affect the energy balance in the atmosphere. Different climate models were run using the same inputs to allow an easy comparison of the results and to understand where the models differ. We found the effect of aerosols is to reduce warming in the atmosphere, but this effect varies between models. Reactions between gases are also important in affecting climate.
Pragati Rai, Jay G. Slowik, Markus Furger, Imad El Haddad, Suzanne Visser, Yandong Tong, Atinderpal Singh, Günther Wehrle, Varun Kumar, Anna K. Tobler, Deepika Bhattu, Liwei Wang, Dilip Ganguly, Neeraj Rastogi, Ru-Jin Huang, Jaroslaw Necki, Junji Cao, Sachchida N. Tripathi, Urs Baltensperger, and André S. H. Prévôt
Atmos. Chem. Phys., 21, 717–730,Short summary
We present a simple conceptual framework based on elemental size distributions and enrichment factors that allows for a characterization of major sources, site-to-site similarities, and local differences and the identification of key information required for efficient policy development. Absolute concentrations are by far the highest in Delhi, followed by Beijing, and then the European cities.
Helle Astrid Kjær, Patrick Zens, Ross Edwards, Martin Olesen, Ruth Mottram, Gabriel Lewis, Christian Terkelsen Holme, Samuel Black, Kasper Holst Lund, Mikkel Schmidt, Dorthe Dahl-Jensen, Bo Vinther, Anders Svensson, Nanna Karlsson, Jason E. Box, Sepp Kipfstuhl, and Paul Vallelonga
The Cryosphere Discuss.,
Preprint under review for TCShort summary
We have reconstructed accumulation in 6 firn cores and 8 snow cores in Northern Greenland and compared with a regional Climate model over Greenland. We find the model underestimate precipitation especially in north-eastern part of the ice cap- an important finding if aiming to reconstruct surface mass balance. Temperatures at 10 meters depth at 6 sites in Greenland were also determined and show a significant warming since the 1990's of 0.9 to 2.5 °C.
Peter Horvath, Hui Tang, Rune Halvorsen, Frode Stordal, Lena Merete Tallaksen, Terje Koren Berntsen, and Anders Bryn
Biogeosciences, 18, 95–112,Short summary
We evaluated the performance of three methods for representing vegetation cover. Remote sensing provided the best match to a reference dataset, closely followed by distribution modelling (DM), whereas the dynamic global vegetation model (DGVM) in CLM4.5BGCDV deviated strongly from the reference. Sensitivity tests show that use of threshold values for predictors identified by DM may improve DGVM performance. The results highlight the potential of using DM in the development of DGVMs.
Jonas Gliß, Augustin Mortier, Michael Schulz, Elisabeth Andrews, Yves Balkanski, Susanne E. Bauer, Anna M. K. Benedictow, Huisheng Bian, Ramiro Checa-Garcia, Mian Chin, Paul Ginoux, Jan J. Griesfeller, Andreas Heckel, Zak Kipling, Alf Kirkevåg, Harri Kokkola, Paolo Laj, Philippe Le Sager, Marianne Tronstad Lund, Cathrine Lund Myhre, Hitoshi Matsui, Gunnar Myhre, David Neubauer, Twan van Noije, Peter North, Dirk J. L. Olivié, Samuel Rémy, Larisa Sogacheva, Toshihiko Takemura, Kostas Tsigaridis, and Svetlana G. Tsyro
Atmos. Chem. Phys., 21, 87–128,Short summary
Simulated aerosol optical properties as well as the aerosol life cycle are investigated for 14 global models participating in the AeroCom initiative. Considerable diversity is found in the simulated aerosol species emissions and lifetimes, also resulting in a large diversity in the simulated aerosol mass, composition, and optical properties. A comparison with observations suggests that, on average, current models underestimate the direct effect of aerosol on the atmosphere radiation budget.
Syuichi Itahashi, Baozhu Ge, Keiichi Sato, Zhe Wang, Junichi Kurokawa, Jiani Tan, Kan Huang, Joshua S. Fu, Xuemei Wang, Kazuyo Yamaji, Tatsuya Nagashima, Jie Li, Mizuo Kajino, Gregory R. Carmichael, and Zifa Wang
Atmos. Chem. Phys. Discuss.,
Preprint under review for ACPShort summary
This study presents the detailed analysis of acid deposition over Southeast Asia based on the Model Inter-Comparison Study for Asia (MICS-Asia) phase III. Simulated wet deposition is evaluated with observation data from the Acid Deposition Monitoring Network in East Asia (EANET). The difficulties of models to capture observation are related to the model performance on precipitation. The precipitation-adjusted approach was applied, and the distribution of wet deposition was successfully revised.
Kine Onsum Moseid, Michael Schulz, Trude Storelvmo, Ingeborg Rian Julsrud, Dirk Olivié, Pierre Nabat, Martin Wild, Jason N. S. Cole, Toshihiko Takemura, Naga Oshima, Susanne E. Bauer, and Guillaume Gastineau
Atmos. Chem. Phys., 20, 16023–16040,Short summary
In this study we compare solar radiation at the surface from observations and Earth system models from 1961 to 2014. We find that the models do not reproduce the so-called
global dimmingas found in observations. Only model experiments with anthropogenic aerosol emissions display any dimming at all. The discrepancies between observations and models are largest in China, which we suggest is in part due to erroneous aerosol precursor emission inventories in the emission dataset used for CMIP6.
Haiyan Ni, Ru-Jin Huang, Max M. Cosijn, Lu Yang, Jie Guo, Junji Cao, and Ulrike Dusek
Atmos. Chem. Phys., 20, 16041–16053,Short summary
We investigated sources of carbonaceous aerosols in Beijing and Xi'an during severe winter haze. Elemental carbon (EC) was dominated by vehicle emissions in Xi’an and coal burning in Beijing. Organic carbon (OC) increment during haze days was driven by the increase in primary and secondary OC (SOC). SOC was more from fossil sources in Beijing than Xi’an, especially during haze days. In Xi’an, no strong day–night differences in EC or OC sources suggest a large accumulation of particles.
Qiyuan Wang, Huikun Liu, Ping Wang, Wenting Dai, Ting Zhang, Youzhi Zhao, Jie Tian, Wenyan Zhang, Yongming Han, and Junji Cao
Atmos. Chem. Phys., 20, 15537–15549,Short summary
Light-absorbing carbonaceous (LAC) aerosol is an important influencing factor for global climate forcing. In this study, we used a receptor model coupling multi-wavelength absorption with chemical species to explore the source-specific LAC optical properties at a tropical marine monsoon climate zone. The results can improve our understanding of the LAC radiative effects caused by ship emissions.
Qiyuan Wang, Li Li, Jiamao Zhou, Jianhuai Ye, Wenting Dai, Huikun Liu, Yong Zhang, Renjian Zhang, Jie Tian, Yang Chen, Yunfei Wu, Weikang Ran, and Junji Cao
Atmos. Chem. Phys., 20, 15427–15442,Short summary
Recently, China has promulgated a series of regulations to reduce air pollutants. The decreased black carbon (BC) and co-emitted pollutants could affect the interactions between BC and other aerosols, which in turn results in changes in BC. Herein, we re-assessed the characteristics of BC of a representative pollution site in northern China in the final year of the Chinese
Action Plan for the Prevention and Control of Air Pollution.
Na Zhao, Xinyi Dong, Joshua S. Fu, Marianne Tronstad Lund, Kengo Sudo, Daven Henze, Tom Kucsera, Yun Fat Lam, Mian Chin, Simone Tilmes, and Kan Huang
Atmos. Chem. Phys. Discuss.,
Preprint under review for ACPShort summary
Black carbon acts as a strong climate forcer, especially in vulnerable pristine regions such as the Arctic. This work utilizes ensemble modeling results from the Task Force Hemispheric Transport of Air Pollution Phase2 to investigate the responses of Arctic black carbon and surface temperature to various source emission reductions. East Asia contributed the most to Arctic black carbon. The response of Arctic temperature to black carbon was substantially more sensitive than the global average.
Robin D. Lamboll, Chris D. Jones, Ragnhild B. Skeie, Stephanie Fiedler, Bjørn H. Samset, Nathan P. Gillett, Joeri Rogelj, and Piers M. Forster
Geosci. Model Dev. Discuss.,
Preprint under review for GMDShort summary
Lockdowns to avoid the spread of COVID-19 have created an unprecedented reduction in human emissions. We can estimate the changes in emissions at a country level, but to make predictions about how this will affect our climate, we need more precise information about where the emissions happen. Here we combine older estimates of where emissions normally occur with very recent estimates of sector activity levels to enable different groups to make simulations of the climatic effects of lockdown.
Hajime Akimoto, Tatsuya Nagashima, Natsumi Kawano, Li Jie, Joshua S. Fu, and Zifa Wang
Atmos. Chem. Phys., 20, 15003–15014,Short summary
In order to perform proper model simulation of ozone near the ground in the coastal area of northeastern Asia, it has been found that it is very important to select appropriate dry deposition velocities of ozone on the oceanic water of specific area of the northwestern Pacific. Empirical measurement of the mixing ratios and dry deposition flux of ozone over the ocean in this area is highly recommended.
Steven T. Turnock, Robert J. Allen, Martin Andrews, Susanne E. Bauer, Makoto Deushi, Louisa Emmons, Peter Good, Larry Horowitz, Jasmin G. John, Martine Michou, Pierre Nabat, Vaishali Naik, David Neubauer, Fiona M. O'Connor, Dirk Olivié, Naga Oshima, Michael Schulz, Alistair Sellar, Sungbo Shim, Toshihiko Takemura, Simone Tilmes, Kostas Tsigaridis, Tongwen Wu, and Jie Zhang
Atmos. Chem. Phys., 20, 14547–14579,Short summary
A first assessment is made of the historical and future changes in air pollutants from models participating in the 6th Coupled Model Intercomparison Project (CMIP6). Substantial benefits to future air quality can be achieved in future scenarios that implement measures to mitigate climate and involve reductions in air pollutant emissions, particularly methane. However, important differences are shown between models in the future regional projection of air pollutants under the same scenario.
Zachary Fair, Mark Flanner, Kelly M. Brunt, Helen Amanda Fricker, and Alex Gardner
The Cryosphere, 14, 4253–4263,Short summary
Ice on glaciers and ice sheets may melt and pond on ice surfaces in summer months. Detection and observation of these meltwater ponds is important for understanding glaciers and ice sheets, and satellite imagery has been used in previous work. However, image-based methods struggle with deep water, so we used data from the Ice, Clouds, and land Elevation Satellite-2 (ICESat-2) and the Airborne Topographic Mapper (ATM) to demonstrate the potential for lidar depth monitoring.
Takuro Michibata, Kentaroh Suzuki, and Toshihiko Takemura
Atmos. Chem. Phys., 20, 13771–13780,Short summary
This work reveals that prognostic precipitation significantly reduces the magnitude of aerosol–cloud interactions (ERFaci), mainly due to the collection process associated with snowflakes and underlying cloud droplets. This precipitation-driven buffering effect, which is missing in traditional GCMs, can explain the model–observation discrepancy in ERFaci. These results underscore the necessity for a prognostic precipitation framework in GCMs for more reliable climate simulations.
Camilla W. Stjern, Bjørn H. Samset, Olivier Boucher, Trond Iversen, Jean-François Lamarque, Gunnar Myhre, Drew Shindell, and Toshihiko Takemura
Atmos. Chem. Phys., 20, 13467–13480,Short summary
The span between the warmest and coldest temperatures over a day is a climate parameter that influences both agriculture and human health. Using data from 10 models, we show how individual climate drivers such as greenhouse gases and aerosols produce distinctly different responses in this parameter in high-emission regions. Given the high uncertainty in future aerosol emissions, this improved understanding of the temperature responses may ultimately help these regions prepare for future changes.
Sara M. Blichner, Moa K. Sporre, Risto Makkonen, and Terje K. Berntsen
Geosci. Model Dev. Discuss.,
Preprint under review for GMDShort summary
Aerosol-cloud interactions is the largest contributor to climate forcing uncertainty. In this study we combine two common approaches to aerosol representation in global models: A sectional scheme, which is closer to first principals, for the smallest particles forming in the atmosphere and a log-modal scheme, which is faster, for the larger particles. With this approach, we improve the aerosol representation compared to observations, while only increasing the computational cost by 15 %.
Augustin Mortier, Jonas Gliß, Michael Schulz, Wenche Aas, Elisabeth Andrews, Huisheng Bian, Mian Chin, Paul Ginoux, Jenny Hand, Brent Holben, Hua Zhang, Zak Kipling, Alf Kirkevåg, Paolo Laj, Thibault Lurton, Gunnar Myhre, David Neubauer, Dirk Olivié, Knut von Salzen, Ragnhild Bieltvedt Skeie, Toshihiko Takemura, and Simone Tilmes
Atmos. Chem. Phys., 20, 13355–13378,Short summary
We present a multiparameter analysis of the aerosol trends over the last 2 decades in the different regions of the world. In most of the regions, ground-based observations show a decrease in aerosol content in both the total atmospheric column and at the surface. The use of climate models, assessed against these observations, reveals however an increase in the total aerosol load, which is not seen with the sole use of observation due to partial coverage in space and time.
Marianne T. Lund, Borgar Aamaas, Camilla W. Stjern, Zbigniew Klimont, Terje K. Berntsen, and Bjørn H. Samset
Earth Syst. Dynam., 11, 977–993,Short summary
Achieving the Paris Agreement temperature goals requires both near-zero levels of long-lived greenhouse gases and deep cuts in emissions of short-lived climate forcers (SLCFs). Here we quantify the near- and long-term global temperature impacts of emissions of individual SLCFs and CO2 from 7 economic sectors in 13 regions in order to provide the detailed knowledge needed to design efficient mitigation strategies at the sectoral and regional levels.
David S. Stevenson, Alcide Zhao, Vaishali Naik, Fiona M. O'Connor, Simone Tilmes, Guang Zeng, Lee T. Murray, William J. Collins, Paul T. Griffiths, Sungbo Shim, Larry W. Horowitz, Lori T. Sentman, and Louisa Emmons
Atmos. Chem. Phys., 20, 12905–12920,Short summary
We present historical trends in atmospheric oxidizing capacity (OC) since 1850 from the latest generation of global climate models and compare these with estimates from measurements. OC controls levels of many key reactive gases, including methane (CH4). We find small model trends up to 1980, then increases of about 9 % up to 2014, disagreeing with (uncertain) measurement-based trends. Major drivers of OC trends are emissions of CH4, NOx, and CO; these will be important for future CH4 trends.
James W. Kirchner, Sarah E. Godsey, Madeline Solomon, Randall Osterhuber, Joseph R. McConnell, and Daniele Penna
Hydrol. Earth Syst. Sci., 24, 5095–5123,Short summary
Streams and groundwaters often show daily cycles in response to snowmelt and evapotranspiration. These typically have a roughly 6 h time lag, which is often interpreted as a travel-time lag. Here we show that it is instead primarily a phase lag that arises because aquifers integrate their inputs over time. We further show how these cycles shift seasonally, mirroring the springtime retreat of snow cover to higher elevations and the seasonal advance and retreat of photosynthetic activity.
Phuc T. M. Ha, Fumikazu Taketani, Yugo Kanaya, Ryoki Matsuda, and Kengo Sudo
Geosci. Model Dev. Discuss.,
Preprint under review for GMDShort summary
Policies to mitigate air pollution acquire understanding of tropospheric oxidizing capacity, which is controlled by several mechanisms includes heterogeneous processes on aerosols and clouds. This study uses a chemistry-climate model CHASER (MIROC) to explore the heterogeneous effects in troposphere for −3 % O3, −2.2 % NOx, +3.3 % CO, and +5.9 % CH4 lifetime. Besides, these processes affect not only polluted areas but also remote areas and can bring challenges to pollution reduction efforts.
Zebedee R. J. Nicholls, Malte Meinshausen, Jared Lewis, Robert Gieseke, Dietmar Dommenget, Kalyn Dorheim, Chen-Shuo Fan, Jan S. Fuglestvedt, Thomas Gasser, Ulrich Golüke, Philip Goodwin, Corinne Hartin, Austin P. Hope, Elmar Kriegler, Nicholas J. Leach, Davide Marchegiani, Laura A. McBride, Yann Quilcaille, Joeri Rogelj, Ross J. Salawitch, Bjørn H. Samset, Marit Sandstad, Alexey N. Shiklomanov, Ragnhild B. Skeie, Christopher J. Smith, Steve Smith, Katsumasa Tanaka, Junichi Tsutsui, and Zhiang Xie
Geosci. Model Dev., 13, 5175–5190,Short summary
Computational limits mean that we cannot run our most comprehensive climate models for all applications of interest. In such cases, reduced complexity models (RCMs) are used. Here, researchers working on 15 different models present the first systematic community effort to evaluate and compare RCMs: the Reduced Complexity Model Intercomparison Project (RCMIP). Our research ensures that users of RCMs can more easily evaluate the strengths, weaknesses and limitations of their tools.
Xiaoning Xie, Gunnar Myhre, Xiaodong Liu, Xinzhou Li, Zhengguo Shi, Hongli Wang, Alf Kirkevåg, Jean-Francois Lamarque, Drew Shindell, Toshihiko Takemura, and Yangang Liu
Atmos. Chem. Phys., 20, 11823–11839,Short summary
Black carbon (BC) and greenhouse gases (GHGs) enhance precipitation minus evaporation (P–E) of Asian summer monsoon (ASM). Further analysis reveals distinct mechanisms controlling BC- and GHG-induced ASM P–E increases. The change in ASM P–E by BC is dominated by the dynamic effect of enhanced large-scale monsoon circulation, the GHG-induced change by the thermodynamic effect of increasing atmospheric water vapor. This results from different atmospheric temperature feedbacks due to BC and GHGs.
Peter Sherman, Meng Gao, Shaojie Song, Alex T. Archibald, Nathan Luke Abraham, Jean-François Lamarque, Drew Shindell, Gregory Faluvegi, and Michael B. McElroy
Atmos. Chem. Phys. Discuss.,
Revised manuscript accepted for ACPShort summary
The aims here are to assess the role of aerosols on India's monsoon precipitation and to determine the relative contributions from Chinese and Indian emissions using CMIP6 models. We find that increased sulfur emissions reduce precipitation, which is primarily dynamically driven due to spatial shifts in convection over the region. A significant increase in precipitation (up to ~ 20 %) is found only when both Indian and Chinese sulfate emissions are regulated.
Kazuyuki Miyazaki, Kevin Bowman, Takashi Sekiya, Henk Eskes, Folkert Boersma, Helen Worden, Nathaniel Livesey, Vivienne H. Payne, Kengo Sudo, Yugo Kanaya, Masayuki Takigawa, and Koji Ogochi
Earth Syst. Sci. Data, 12, 2223–2259,Short summary
This study presents the results from the Tropospheric Chemistry Reanalysis version 2 (TCR-2) for 2005–2018 obtained from the assimilation of multiple satellite measurements of ozone, CO, NO2, HNO3, and SO2 from the OMI, SCIAMACHY, GOME-2, TES, MLS, and MOPITT instruments. The evaluation results demonstrate the capability of the reanalysis products to improve understanding of the processes controlling variations in atmospheric composition, including long-term changes in air quality and emissions.
Baozhu Ge, Syuichi Itahashi, Keiichi Sato, Danhui Xu, Junhua Wang, Fan Fan, Qixin Tan, Joshua S. Fu, Xuemei Wang, Kazuyo Yamaji, Tatsuya Nagashima, Jie Li, Mizuo Kajino, Hong Liao, Meigen Zhang, Zhe Wang, Meng Li, Jung-Hun Woo, Junichi Kurokawa, Yuepeng Pan, Qizhong Wu, Xuejun Liu, and Zifa Wang
Atmos. Chem. Phys., 20, 10587–10610,Short summary
Performances of the simulated deposition for different reduced N (Nr) species in China were conducted with the Model Inter-Comparison Study for Asia. Results showed that simulated wet deposition of oxidized N was overestimated in northeastern China and underestimated in south China, but Nr was underpredicted in all regions by all models. Oxidized N has larger uncertainties than Nr, indicating that the chemical reaction process is one of the most importance factors affecting model performance.
Li Zhang, Meiyun Lin, Andrew O. Langford, Larry W. Horowitz, Christoph J. Senff, Elizabeth Klovenski, Yuxuan Wang, Raul J. Alvarez II, Irina Petropavlovskikh, Patrick Cullis, Chance W. Sterling, Jeff Peischl, Thomas B. Ryerson, Steven S. Brown, Zachary C. J. Decker, Guillaume Kirgis, and Stephen Conley
Atmos. Chem. Phys., 20, 10379–10400,Short summary
Measuring and quantifying the sources of elevated springtime ozone in the southwestern US is challenging but relevant to the implications for control policy. Here we use intensive field measurements and two global models to study ozone sources in the region. We find that ozone from the stratosphere, wildfires, and Asia is an important source of high-ozone events in the region. Our analysis also helps understand the uncertainties in ozone simulations with individual models.
María A. Burgos, Elisabeth Andrews, Gloria Titos, Angela Benedetti, Huisheng Bian, Virginie Buchard, Gabriele Curci, Zak Kipling, Alf Kirkevåg, Harri Kokkola, Anton Laakso, Julie Letertre-Danczak, Marianne T. Lund, Hitoshi Matsui, Gunnar Myhre, Cynthia Randles, Michael Schulz, Twan van Noije, Kai Zhang, Lucas Alados-Arboledas, Urs Baltensperger, Anne Jefferson, James Sherman, Junying Sun, Ernest Weingartner, and Paul Zieger
Atmos. Chem. Phys., 20, 10231–10258,Short summary
We investigate how well models represent the enhancement in scattering coefficients due to particle water uptake, and perform an evaluation of several implementation schemes used in ten Earth system models. Our results show the importance of the parameterization of hygroscopicity and model chemistry as drivers of some of the observed diversity amongst model estimates. The definition of dry conditions and the phenomena taking place in this relative humidity range also impact the model evaluation.
Mengdi Song, Xin Li, Suding Yang, Xuena Yu, Songxiu Zhou, Yiming Yang, Shiyi Chen, Huabin Dong, Keren Liao, Qi Chen, Keding Lu, Ningning Zhang, Junji Cao, Liming Zeng, and Yuanhang Zhang
Atmos. Chem. Phys. Discuss.,
Revised manuscript accepted for ACPShort summary
Due to their lower diffusion capacities and higher conversion capacities, urban areas in Xi’an experienced severe ozone pollution in the summer, and the concentration and proportion of oxygenated VOCs increased significantly during ozone pollution days. Xi'an has a strong local emission source of VOCs, and vehicle exhaust was the primary VOC source. In addition, alkenes, aromatics, and OVOCs played a dominant role in secondary transformations.
Matt Amos, Paul J. Young, J. Scott Hosking, Jean-François Lamarque, N. Luke Abraham, Hideharu Akiyoshi, Alexander T. Archibald, Slimane Bekki, Makoto Deushi, Patrick Jöckel, Douglas Kinnison, Ole Kirner, Markus Kunze, Marion Marchand, David A. Plummer, David Saint-Martin, Kengo Sudo, Simone Tilmes, and Yousuke Yamashita
Atmos. Chem. Phys., 20, 9961–9977,Short summary
We present an updated projection of Antarctic ozone hole recovery using an ensemble of chemistry–climate models. To do so, we employ a method, more advanced and skilful than the current multi-model mean standard, which is applicable to other ensemble analyses. It calculates the performance and similarity of the models, which we then use to weight the model. Calculating model similarity allows us to account for models which are constructed from similar components.
Anders Svensson, Dorthe Dahl-Jensen, Jørgen Peder Steffensen, Thomas Blunier, Sune O. Rasmussen, Bo M. Vinther, Paul Vallelonga, Emilie Capron, Vasileios Gkinis, Eliza Cook, Helle Astrid Kjær, Raimund Muscheler, Sepp Kipfstuhl, Frank Wilhelms, Thomas F. Stocker, Hubertus Fischer, Florian Adolphi, Tobias Erhardt, Michael Sigl, Amaelle Landais, Frédéric Parrenin, Christo Buizert, Joseph R. McConnell, Mirko Severi, Robert Mulvaney, and Matthias Bigler
Clim. Past, 16, 1565–1580,Short summary
We identify signatures of large bipolar volcanic eruptions in Greenland and Antarctic ice cores during the last glacial period, which allows for a precise temporal alignment of the ice cores. Thereby the exact timing of unexplained, abrupt climatic changes occurring during the last glacial period can be determined in a global context. The study thus provides a step towards a full understanding of elements of the climate system that may also play an important role in the future.
Christopher J. Smith, Ryan J. Kramer, Gunnar Myhre, Kari Alterskjær, William Collins, Adriana Sima, Olivier Boucher, Jean-Louis Dufresne, Pierre Nabat, Martine Michou, Seiji Yukimoto, Jason Cole, David Paynter, Hideo Shiogama, Fiona M. O'Connor, Eddy Robertson, Andy Wiltshire, Timothy Andrews, Cécile Hannay, Ron Miller, Larissa Nazarenko, Alf Kirkevåg, Dirk Olivié, Stephanie Fiedler, Anna Lewinschal, Chloe Mackallah, Martin Dix, Robert Pincus, and Piers M. Forster
Atmos. Chem. Phys., 20, 9591–9618,Short summary
The spread in effective radiative forcing for both CO2 and aerosols is narrower in the latest CMIP6 (Coupled Model Intercomparison Project) generation than in CMIP5. For the case of CO2 it is likely that model radiation parameterisations have improved. Tropospheric and stratospheric radiative adjustments to the forcing behave differently for different forcing agents, and there is still significant diversity in how clouds respond to forcings, particularly for total anthropogenic forcing.
Robert J. Allen, Steven Turnock, Pierre Nabat, David Neubauer, Ulrike Lohmann, Dirk Olivié, Naga Oshima, Martine Michou, Tongwen Wu, Jie Zhang, Toshihiko Takemura, Michael Schulz, Kostas Tsigaridis, Susanne E. Bauer, Louisa Emmons, Larry Horowitz, Vaishali Naik, Twan van Noije, Tommi Bergman, Jean-Francois Lamarque, Prodromos Zanis, Ina Tegen, Daniel M. Westervelt, Philippe Le Sager, Peter Good, Sungbo Shim, Fiona O'Connor, Dimitris Akritidis, Aristeidis K. Georgoulias, Makoto Deushi, Lori T. Sentman, Jasmin G. John, Shinichiro Fujimori, and William J. Collins
Atmos. Chem. Phys., 20, 9641–9663,
Ru-Jin Huang, Yao He, Jing Duan, Yongjie Li, Qi Chen, Yan Zheng, Yang Chen, Weiwei Hu, Chunshui Lin, Haiyan Ni, Wenting Dai, Junji Cao, Yunfei Wu, Renjian Zhang, Wei Xu, Jurgita Ovadnevaite, Darius Ceburnis, Thorsten Hoffmann, and Colin D. O'Dowd
Atmos. Chem. Phys., 20, 9101–9114,Short summary
We systematically compared the submicron particle (PM1) processes in haze days with low and high relative humidity (RH) in wintertime Beijing. Nitrate had similar daytime growth rates in low-RH and high-RH pollution. OOA had a higher growth rate in low-RH pollution than in high-RH pollution. Sulfate had a decreasing trend in low-RH pollution, while it increased significantly in high-RH pollution. This distinction may be explained by the different processes affected by meteorological conditions.
Moa K. Sporre, Sara M. Blichner, Roland Schrödner, Inger H. H. Karset, Terje K. Berntsen, Twan van Noije, Tommi Bergman, Declan O'Donnell, and Risto Makkonen
Atmos. Chem. Phys., 20, 8953–8973,Short summary
We investigate how emissions and parameters in current SOA parameterisations in three ESMs affect both the resulting SOA in the models and the impact this has on climate through the direct and indirect aerosol effects. The SOA changes induce very different responses in the models, especially in terms of the indirect aerosol effect. This introduces uncertainties in ESM estimates of SOA climate impact through feedbacks in a warming climate and through anthropogenic land use change.
Gunnar Myhre, Bjørn H. Samset, Christian W. Mohr, Kari Alterskjær, Yves Balkanski, Nicolas Bellouin, Mian Chin, James Haywood, Øivind Hodnebrog, Stefan Kinne, Guangxing Lin, Marianne T. Lund, Joyce E. Penner, Michael Schulz, Nick Schutgens, Ragnhild B. Skeie, Philip Stier, Toshihiko Takemura, and Kai Zhang
Atmos. Chem. Phys., 20, 8855–8865,Short summary
The radiative forcing of the direct aerosol effects can be decomposed into clear-sky and cloudy-sky portions. In this study we use observational methods and two sets of multi-model global aerosol simulations over the industrial era to show that the contribution from cloudy-sky regions is likely weak.
Prodromos Zanis, Dimitris Akritidis, Aristeidis K. Georgoulias, Robert J. Allen, Susanne E. Bauer, Olivier Boucher, Jason Cole, Ben Johnson, Makoto Deushi, Martine Michou, Jane Mulcahy, Pierre Nabat, Dirk Olivié, Naga Oshima, Adriana Sima, Michael Schulz, Toshihiko Takemura, and Konstantinos Tsigaridis
Atmos. Chem. Phys., 20, 8381–8404,Short summary
In this work, we use Coupled Model Intercomparison Project Phase 6 (CMIP6) simulations from 10 Earth system models (ESMs) and general circulation models (GCMs) to study the fast climate responses on pre-industrial climate, due to present-day aerosols. All models carried out two sets of simulations: a control experiment with all forcings set to the year 1850 and a perturbation experiment with all forcings identical to the control, except for aerosols with precursor emissions set to the year 2014.
Nicolas Bellouin, Will Davies, Keith P. Shine, Johannes Quaas, Johannes Mülmenstädt, Piers M. Forster, Chris Smith, Lindsay Lee, Leighton Regayre, Guy Brasseur, Natalia Sudarchikova, Idir Bouarar, Olivier Boucher, and Gunnar Myhre
Earth Syst. Sci. Data, 12, 1649–1677,Short summary
Quantifying the imbalance in the Earth's energy budget caused by human activities is important to understand and predict climate changes. This study presents new estimates of the imbalance caused by changes in atmospheric concentrations of carbon dioxide, methane, ozone, and particles of pollution. Over the period 2003–2017, the overall imbalance has been positive, indicating that the climate system has gained energy and will warm further.
Tao Tang, Drew Shindell, Yuqiang Zhang, Apostolos Voulgarakis, Jean-Francois Lamarque, Gunnar Myhre, Camilla W. Stjern, Gregory Faluvegi, and Bjørn H. Samset
Atmos. Chem. Phys., 20, 8251–8266,Short summary
By using climate simulations, we found that both CO2 and black carbon aerosols could reduce low-level cloud cover, which is mainly due to changes in relative humidity, cloud water, dynamics, and stability. Because the impact of cloud on solar radiation is in effect only during daytime, such cloud reduction could enhance solar heating, thereby raising the daily maximum temperature by 10–50 %, varying by region, which has great implications for extreme climate events and socioeconomic activity.
Marielle Saunois, Ann R. Stavert, Ben Poulter, Philippe Bousquet, Josep G. Canadell, Robert B. Jackson, Peter A. Raymond, Edward J. Dlugokencky, Sander Houweling, Prabir K. Patra, Philippe Ciais, Vivek K. Arora, David Bastviken, Peter Bergamaschi, Donald R. Blake, Gordon Brailsford, Lori Bruhwiler, Kimberly M. Carlson, Mark Carrol, Simona Castaldi, Naveen Chandra, Cyril Crevoisier, Patrick M. Crill, Kristofer Covey, Charles L. Curry, Giuseppe Etiope, Christian Frankenberg, Nicola Gedney, Michaela I. Hegglin, Lena Höglund-Isaksson, Gustaf Hugelius, Misa Ishizawa, Akihiko Ito, Greet Janssens-Maenhout, Katherine M. Jensen, Fortunat Joos, Thomas Kleinen, Paul B. Krummel, Ray L. Langenfelds, Goulven G. Laruelle, Licheng Liu, Toshinobu Machida, Shamil Maksyutov, Kyle C. McDonald, Joe McNorton, Paul A. Miller, Joe R. Melton, Isamu Morino, Jurek Müller, Fabiola Murguia-Flores, Vaishali Naik, Yosuke Niwa, Sergio Noce, Simon O'Doherty, Robert J. Parker, Changhui Peng, Shushi Peng, Glen P. Peters, Catherine Prigent, Ronald Prinn, Michel Ramonet, Pierre Regnier, William J. Riley, Judith A. Rosentreter, Arjo Segers, Isobel J. Simpson, Hao Shi, Steven J. Smith, L. Paul Steele, Brett F. Thornton, Hanqin Tian, Yasunori Tohjima, Francesco N. Tubiello, Aki Tsuruta, Nicolas Viovy, Apostolos Voulgarakis, Thomas S. Weber, Michiel van Weele, Guido R. van der Werf, Ray F. Weiss, Doug Worthy, Debra Wunch, Yi Yin, Yukio Yoshida, Wenxin Zhang, Zhen Zhang, Yuanhong Zhao, Bo Zheng, Qing Zhu, Qiuan Zhu, and Qianlai Zhuang
Earth Syst. Sci. Data, 12, 1561–1623,Short summary
Understanding and quantifying the global methane (CH4) budget is important for assessing realistic pathways to mitigate climate change. We have established a consortium of multidisciplinary scientists under the umbrella of the Global Carbon Project to synthesize and stimulate new research aimed at improving and regularly updating the global methane budget. This is the second version of the review dedicated to the decadal methane budget, integrating results of top-down and bottom-up estimates.
Javier Alejandro Barrera, Rafael Pedro Fernandez, Fernando Iglesias-Suarez, Carlos Alberto Cuevas, Jean-Francois Lamarque, and Alfonso Saiz-Lopez
Atmos. Chem. Phys., 20, 8083–8102,Short summary
The inclusion of biogenic very short-lived bromocarbons (VSLBr) in the CAM-chem model improves the model–satellite agreement of the total ozone columns at mid-latitudes and drives a persistent hemispheric asymmetry in lowermost stratospheric ozone loss. The seasonal VSLBr impact on mid-latitude lowermost stratospheric ozone is influenced by the heterogeneous reactivation processes of inorganic chlorine on ice crystals, with a clear increase in ozone destruction during spring and winter.
Daniele Visioni, Giovanni Pitari, Vincenzo Rizi, Marco Iarlori, Irene Cionni, Ilaria Quaglia, Hideharu Akiyoshi, Slimane Bekki, Neal Butchart, Martin Chipperfield, Makoto Deushi, Sandip S. Dhomse, Rolando Garcia, Patrick Joeckel, Douglas Kinnison, Jean-François Lamarque, Marion Marchand, Martine Michou, Olaf Morgenstern, Tatsuya Nagashima, Fiona M. O'Connor, Luke D. Oman, David Plummer, Eugene Rozanov, David Saint-Martin, Robyn Schofield, John Scinocca, Andrea Stenke, Kane Stone, Kengo Sudo, Taichu Y. Tanaka, Simone Tilmes, Holger Tost, Yousuke Yamashita, and Guang Zeng
Atmos. Chem. Phys. Discuss.,
Revised manuscript has not been submittedShort summary
In this work we analyse the trend in ozone profiles taken at L'Aquila (Italy, 42.4° N) for seventeen years, between 2000 and 2016 and compare them against already available measured ozone trends. We try to understand and explain the observed trends at various heights in light of the simulations from seventeen different model, highlighting the contribution of changes in circulation and chemical ozone loss during this time period.
Jiani Tan, Joshua S. Fu, Gregory R. Carmichael, Syuichi Itahashi, Zhining Tao, Kan Huang, Xinyi Dong, Kazuyo Yamaji, Tatsuya Nagashima, Xuemei Wang, Yiming Liu, Hyo-Jung Lee, Chuan-Yao Lin, Baozhu Ge, Mizuo Kajino, Jia Zhu, Meigen Zhang, Hong Liao, and Zifa Wang
Atmos. Chem. Phys., 20, 7393–7410,Short summary
This study evaluated the performance of 12 chemical transport models from MICS-Asia III for predicting the particulate matter (PM) over East Asia. Four model processes were investigated as the possible reasons for model bias with measurements and the factors causing inconsistent predictions of PM from different models: (1) model inputs, (2) gas–particle conversion, (3) dust emission modules and (4) removal mechanisms (wet and dry depositions). The influence of each process was discussed.
Garry D. Hayman, Edward Comyn-Platt, Chris Huntingford, Anna B. Harper, Tom Powell, Peter M. Cox, William Collins, Christopher Webber, Jason Lowe, Stephen Sitch, Joanna I. House, Jonathan C. Doelman, Detlef P. van Vuuren, Sarah E. Chadburn, Eleanor Burke, and Nicola Gedney
Earth Syst. Dynam. Discuss.,
Revised manuscript under review for ESDShort summary
In the Paris Climate Agreement, countries agreed to keep global warming since pre-industrial times below 2 °C and ideally below 1.5 °C, requiring major reductions in greenhouse gas emissions. We investigate the regional effectiveness of lowering methane emissions from human activities, (re)afforestation, and growing bioenergy crops. Methane reduction always helps, especially for major methane-emitting regions. However, the preferred land-management strategy and its effectiveness is more variable.
Yonggang Xue, Yu Huang, Steven Sai Hang Ho, Long Chen, Liqin Wang, Shuncheng Lee, and Junji Cao
Atmos. Chem. Phys., 20, 5425–5436,Short summary
Particulate active metallic oxides in dust were proposed to influence the photochemical reactions of ambient volatile organic compounds (VOCs). A case study investigated the origin and transformation of VOCs during a windblown dust-to-haze pollution episode. In the dust event, a sharp decrease in VOC loading and aging of their components was observed. An increase in Ti and Fe and a fast decrease in trans-/cis-2-butene ratios demonstrated that dust can accelerate the oxidation of ambient VOCs.
Jianjun Li, Qi Zhang, Gehui Wang, Jin Li, Can Wu, Lang Liu, Jiayuan Wang, Wenqing Jiang, Lijuan Li, Kin Fai Ho, and Junji Cao
Atmos. Chem. Phys., 20, 4889–4904,Short summary
We examined light absorption properties and molecular composition of water-soluble (WS) and water-insoluble (WI) BrC in PM2.5 collected from northwest China. We found that photochemical formation contributes significantly to light absorption of WI-BrC in summer, whereas aqueous-phase reactions play an important role in secondary WS-BrC formation in winter. BrC was estimated to account for 1.36 % and 3.74 %, respectively, of total down-welling solar radiation in the UV range in summer and winter.
Oliver Wild, Apostolos Voulgarakis, Fiona O'Connor, Jean-François Lamarque, Edmund M. Ryan, and Lindsay Lee
Atmos. Chem. Phys., 20, 4047–4058,Short summary
Global models of tropospheric chemistry and transport show a persistent diversity in results that has not been fully explained. We demonstrate the first use of global sensitivity analysis consistently across three independent models to explore these differences and reveal both clear similarities and surprising differences which have important implications for our assessment of future atmospheric composition change.
Jing Duan, Ru-Jin Huang, Yongjie Li, Qi Chen, Yan Zheng, Yang Chen, Chunshui Lin, Haiyan Ni, Meng Wang, Jurgita Ovadnevaite, Darius Ceburnis, Chunying Chen, Douglas R. Worsnop, Thorsten Hoffmann, Colin O'Dowd, and Junji Cao
Atmos. Chem. Phys., 20, 3793–3807,Short summary
We characterized secondary aerosol formation in Beijing. Our results showed that relative humidity (RH) and Ox have opposite effects on sulfate and nitrate formation in summer and winter. The wintertime more-oxidized OOA (MO-OOA) showed a good correlation with aerosol liquid water content (ALWC). Meanwhile, the dependence of less-oxidized OOA (LO-OOA) and the mass ratio of LO-OOA to MO-OOA in Ox both degraded when RH > 60 %, suggesting that RH or ALWC may also affect LO-OOA formation.
Maria Sand, Terje K. Berntsen, Annica M. L. Ekman, Hans-Christen Hansson, and Anna Lewinschal
Atmos. Chem. Phys., 20, 3079–3089,Short summary
There has been a growing interest in reducing emissions of soot particles to slow global warming and improve air quality. However, estimating the effect of reduced emissions is complex, as soot particles absorb solar radiation and influence heating rates, clouds, and humidity and can influence climate far outside their emission region. Here we investigate the impact of soot emitted in four major emissions areas, using different emissions rates, to see whether location and magnitude matter.
Daniel M. Westervelt, Nora R. Mascioli, Arlene M. Fiore, Andrew J. Conley, Jean-François Lamarque, Drew T. Shindell, Greg Faluvegi, Michael Previdi, Gustavo Correa, and Larry W. Horowitz
Atmos. Chem. Phys., 20, 3009–3027,Short summary
We use three Earth system models to estimate the impact of regional air pollutant emissions reductions on global and regional surface temperature. We find that removing human-caused air pollutant emissions from certain world regions (such as the USA) results in warming of up to 0.15 °C. We use our model output to calculate simple climate metrics that will allow for regional-scale climate impact estimates without the use of computationally demanding computer models.
Kirstin Hoffmann, Francisco Fernandoy, Hanno Meyer, Elizabeth R. Thomas, Marcelo Aliaga, Dieter Tetzner, Johannes Freitag, Thomas Opel, Jorge Arigony-Neto, Christian Florian Göbel, Ricardo Jaña, Delia Rodríguez Oroz, Rebecca Tuckwell, Emily Ludlow, Joseph R. McConnell, and Christoph Schneider
The Cryosphere, 14, 881–904,
Syuichi Itahashi, Baozhu Ge, Keiichi Sato, Joshua S. Fu, Xuemei Wang, Kazuyo Yamaji, Tatsuya Nagashima, Jie Li, Mizuo Kajino, Hong Liao, Meigen Zhang, Zhe Wang, Meng Li, Junichi Kurokawa, Gregory R. Carmichael, and Zifa Wang
Atmos. Chem. Phys., 20, 2667–2693,Short summary
This study gives an overview of acid deposition from the Model Inter-Comparison Study for Asia (MICS-Asia) phase III. Wet deposition simulated by a total of nine models is evaluated with observation data from the Acid Deposition Monitoring Network in East Asia (EANET). The total deposition maps comparing to emissions over Asia are presented. To seek a way to improve the model performance, ensemble approaches and the precipitation-adjusted method are discussed.
James Keeble, Birgit Hassler, Antara Banerjee, Ramiro Checa-Garcia, Gabriel Chiodo, Sean Davis, Veronika Eyring, Paul T. Griffiths, Olaf Morgenstern, Peer Nowack, Guang Zeng, Jiankai Zhang, Greg Bodeker, David Cugnet, Gokhan Danabasoglu, Makoto Deushi, Larry W. Horowitz, Lijuan Li, Martine Michou, Michael J. Mills, Pierre Nabat, Sungsu Park, and Tongwen Wu
Atmos. Chem. Phys. Discuss.,
Revised manuscript accepted for ACPShort summary
Stratospheric ozone and water vapour are key components of the Earth system, and changes to both have important impacts on global and regional climate. We evaluate changes to these species from 1850-2100 in the new generation of CMIP6 models. There is good agreement between the multi-model mean and observations, although there is substantial variation between the individual models. The future evolution of both ozone and water vapour is strongly dependent on the assumed future emissions scenario.
Karl M. Seltzer, Drew T. Shindell, Prasad Kasibhatla, and Christopher S. Malley
Atmos. Chem. Phys., 20, 1757–1775,Short summary
Long-term exposure to ambient ozone is associated with a variety of impacts, including adverse human-health effects and reduced commercial crop yields. We apply machine learning to empirically model long-term O3 exposure over the continental United States from 2000 to 2015 and generate a measurement-based assessment of impacts on human health and crop yields. Notably, our results illustrate how different conclusions regarding historical impacts can be drawn through the use of varying metrics.
Paul T. Griffiths, Lee T. Murray, Guang Zeng, Alexander T. Archibald, Louisa K. Emmons, Ian Galbally, Birgit Hassler, Larry W. Horowitz, James Keeble, Jane Liu, Omid Moeini, Vaishali Naik, Fiona M. O'Connor, Youngsub Matthew Shin, David Tarasick, Simone Tilmes, Steven T. Turnock, Oliver Wild, Paul J. Young, and Prodromos Zanis
Atmos. Chem. Phys. Discuss.,
Revised manuscript accepted for ACPShort summary
We analyse the CMIP6 historical and future simulations for tropospheric ozone, a species which is important for many aspects of atmospheric chemistry. We show that the current generation of models agrees well with observations, being particularly successful in capturing trends in surface ozone and its vertical distribution in the troposphere. We analyse the factors that control ozone, and show that they evolve over the period of the CMIP6 experiments.
Julie M. Nicely, Bryan N. Duncan, Thomas F. Hanisco, Glenn M. Wolfe, Ross J. Salawitch, Makoto Deushi, Amund S. Haslerud, Patrick Jöckel, Béatrice Josse, Douglas E. Kinnison, Andrew Klekociuk, Michael E. Manyin, Virginie Marécal, Olaf Morgenstern, Lee T. Murray, Gunnar Myhre, Luke D. Oman, Giovanni Pitari, Andrea Pozzer, Ilaria Quaglia, Laura E. Revell, Eugene Rozanov, Andrea Stenke, Kane Stone, Susan Strahan, Simone Tilmes, Holger Tost, Daniel M. Westervelt, and Guang Zeng
Atmos. Chem. Phys., 20, 1341–1361,Short summary
Differences in methane lifetime among global models are large and poorly understood. We use a neural network method and simulations from the Chemistry Climate Model Initiative to quantify the factors influencing methane lifetime spread among models and variations over time. UV photolysis, tropospheric ozone, and nitrogen oxides drive large model differences, while the same factors plus specific humidity contribute to a decreasing trend in methane lifetime between 1980 and 2015.
Joseph M. Cook, Andrew J. Tedstone, Christopher Williamson, Jenine McCutcheon, Andrew J. Hodson, Archana Dayal, McKenzie Skiles, Stefan Hofer, Robert Bryant, Owen McAree, Andrew McGonigle, Jonathan Ryan, Alexandre M. Anesio, Tristram D. L. Irvine-Fynn, Alun Hubbard, Edward Hanna, Mark Flanner, Sathish Mayanna, Liane G. Benning, Dirk van As, Marian Yallop, James B. McQuaid, Thomas Gribbin, and Martyn Tranter
The Cryosphere, 14, 309–330,Short summary
Melting of the Greenland Ice Sheet (GrIS) is a major source of uncertainty for sea level rise projections. Ice-darkening due to the growth of algae has been recognized as a potential accelerator of melting. This paper measures and models the algae-driven ice melting and maps the algae over the ice sheet for the first time. We estimate that as much as 13 % total runoff from the south-western GrIS can be attributed to these algae, showing that they must be included in future mass balance models.
Kazuyuki Miyazaki, Kevin W. Bowman, Keiya Yumimoto, Thomas Walker, and Kengo Sudo
Atmos. Chem. Phys., 20, 931–967,Short summary
We introduce a multi-model, multi-constituent chemical data assimilation framework that directly accounts for model error in transport and chemistry by integrating a portfolio of forward chemical transport models. The assimilation was able to reduce ensemble forward model spread and bias relative to independent measurements. Diagnostic information readily available from the framework has the potential to improve chemical predictions through relationships such as emergent constraints.
Jian He, Vaishali Naik, Larry W. Horowitz, Ed Dlugokencky, and Kirk Thoning
Atmos. Chem. Phys., 20, 805–827,Short summary
In this work, methane representation in AM4.1 is improved by optimizing CH4 emissions to match surface observations. We find increases in CH4 sources balanced by increases in sinks lead to CH4 stabilization during 1999–2006, and anthropogenic sources (e.g., agriculture, energy, and waste) are more likely major contributors to the renewed growth after 2006. Increases in CH4 emissions and decreases in OH levels during 2008–2015 prolong CH4 lifetime and amplify methane response to emission changes.
Edward Gryspeerdt, Johannes Mülmenstädt, Andrew Gettelman, Florent F. Malavelle, Hugh Morrison, David Neubauer, Daniel G. Partridge, Philip Stier, Toshihiko Takemura, Hailong Wang, Minghuai Wang, and Kai Zhang
Atmos. Chem. Phys., 20, 613–623,Short summary
Aerosol radiative forcing is a key uncertainty in our understanding of the human forcing of the climate, with much of this uncertainty coming from aerosol impacts on clouds. Observation-based estimates of the radiative forcing are typically smaller than those from global models, but it is not clear if they are more reliable. This work shows how the forcing components in global climate models can be identified, highlighting similarities between the two methods and areas for future investigation.
Le Kuai, Kevin W. Bowman, Kazuyuki Miyazaki, Makoto Deushi, Laura Revell, Eugene Rozanov, Fabien Paulot, Sarah Strode, Andrew Conley, Jean-François Lamarque, Patrick Jöckel, David A. Plummer, Luke D. Oman, Helen Worden, Susan Kulawik, David Paynter, Andrea Stenke, and Markus Kunze
Atmos. Chem. Phys., 20, 281–301,Short summary
The tropospheric ozone increase from pre-industrial to the present day leads to a radiative forcing. The top-of-atmosphere outgoing fluxes at the ozone band are controlled by ozone, water vapor, and temperature. We demonstrate a method to attribute the models’ flux biases to these key players using satellite-constrained instantaneous radiative kernels. The largest spread between models is found in the tropics, mainly driven by ozone and then water vapor.
Lei Kong, Xiao Tang, Jiang Zhu, Zifa Wang, Joshua S. Fu, Xuemei Wang, Syuichi Itahashi, Kazuyo Yamaji, Tatsuya Nagashima, Hyo-Jung Lee, Cheol-Hee Kim, Chuan-Yao Lin, Lei Chen, Meigen Zhang, Zhining Tao, Jie Li, Mizuo Kajino, Hong Liao, Zhe Wang, Kengo Sudo, Yuesi Wang, Yuepeng Pan, Guiqian Tang, Meng Li, Qizhong Wu, Baozhu Ge, and Gregory R. Carmichael
Atmos. Chem. Phys., 20, 181–202,Short summary
Evaluation and uncertainty investigation of NO2, CO and NH3 modeling over China were conducted in this study using 14 chemical transport model results from MICS-Asia III. All models largely underestimated CO concentrations and showed very poor performance in reproducing the observed monthly variations of NH3 concentrations. Potential factors related to such deficiencies are investigated and discussed in this paper.
Bing Pu, Paul Ginoux, Huan Guo, N. Christina Hsu, John Kimball, Beatrice Marticorena, Sergey Malyshev, Vaishali Naik, Norman T. O'Neill, Carlos Pérez García-Pando, Juliette Paireau, Joseph M. Prospero, Elena Shevliakova, and Ming Zhao
Atmos. Chem. Phys., 20, 55–81,Short summary
Dust emission initiates when surface wind velocities exceed a threshold depending on soil and surface characteristics and varying spatially and temporally. Climate models widely use wind erosion thresholds. The climatological monthly global distribution of the wind erosion threshold, Vthreshold, is retrieved using satellite and reanalysis products and improves the simulation of dust frequency, magnitude, and the seasonal cycle in the Geophysical Fluid Dynamics Laboratory land–atmosphere model.
Haiyan Ni, Ru-Jin Huang, Junji Cao, Jie Guo, Haoyue Deng, and Ulrike Dusek
Atmos. Chem. Phys., 19, 15609–15628,Short summary
We present a 1-year source apportionment record of carbonaceous aerosols in Xi'an, China. Biomass burning strongly increases in winter, while seasonal changes of coal and liquid fossil fuel combustion are moderate. We find strong evidence for fossil secondary OC formation during the warm period that is further enhanced in stagnant, polluted conditions due to longer atmospheric residence times. At the same time we find that water-insoluble (primary) fossil is lost due to photochemical processing.
Niccolò Maffezzoli, Paul Vallelonga, Ross Edwards, Alfonso Saiz-Lopez, Clara Turetta, Helle Astrid Kjær, Carlo Barbante, Bo Vinther, and Andrea Spolaor
Clim. Past, 15, 2031–2051,Short summary
This study provides the first ice-core-based history of sea ice in the North Atlantic Ocean, reaching 120 000 years back in time. This record was obtained from bromine and sodium measurements in the RECAP ice core, drilled in east Greenland. We found that, during the last deglaciation, sea ice started to melt ~ 17 500 years ago. Over the 120 000 years of the last glacial cycle, sea ice extent was maximal during MIS2, while minimum sea ice extent exists for the Holocene.
Juan Pablo Corella, Niccolo Maffezzoli, Carlos Alberto Cuevas, Paul Vallelonga, Andrea Spolaor, Giulio Cozzi, Juliane Müller, Bo Vinther, Carlo Barbante, Helle Astrid Kjær, Ross Edwards, and Alfonso Saiz-Lopez
Clim. Past, 15, 2019–2030,Short summary
This study provides the first reconstruction of atmospheric iodine levels in the Arctic during the last 11 700 years from an ice core record in coastal Greenland. Dramatic shifts in iodine level variability coincide with abrupt climatic transitions in the North Atlantic. Since atmospheric iodine levels have significant environmental and climatic implications, this study may serve as a past analog to predict future changes in Arctic climate in response to global warming.
Borgar Aamaas, Terje Koren Berntsen, and Bjørn Hallvard Samset
Atmos. Chem. Phys., 19, 15235–15245,Short summary
Cutting short-lived pollutants can help keep cool the climate – but only if we are clever. We investigate how regional temperatures may change in response to different packages of air quality measures. One package consists of mitigation measures that mainly target emissions that are known to result in a cooler climate, while in the other, emissions are cut as much as technically possible in response to air quality concerns. We estimate the different contributions from various sectors and region.
Jun Zhou, Miriam Elser, Ru-Jin Huang, Manuel Krapf, Roman Fröhlich, Deepika Bhattu, Giulia Stefenelli, Peter Zotter, Emily A. Bruns, Simone M. Pieber, Haiyan Ni, Qiyuan Wang, Yichen Wang, Yaqing Zhou, Chunying Chen, Mao Xiao, Jay G. Slowik, Samuel Brown, Laure-Estelle Cassagnes, Kaspar R. Daellenbach, Thomas Nussbaumer, Marianne Geiser, André S. H. Prévôt, Imad El-Haddad, Junji Cao, Urs Baltensperger, and Josef Dommen
Atmos. Chem. Phys., 19, 14703–14720,Short summary
Reactive oxygen species (ROS) are believed to contribute to the adverse health effects of aerosols. We measured particle-bound ROS (PB-ROS) with an online instrument in two distinct environments, i.e., Beijing (China) and Bern (Switzerland). In both cities these exogenic ROS are predominantly related to secondary organic aerosol (SOA). PB-ROS content in SOA from various anthropogenic emission sources tested in the laboratory was comparable to that in the ambient measurements.
Elizabeth Asher, Rebecca S. Hornbrook, Britton B. Stephens, Doug Kinnison, Eric J. Morgan, Ralph F. Keeling, Elliot L. Atlas, Sue M. Schauffler, Simone Tilmes, Eric A. Kort, Martin S. Hoecker-Martínez, Matt C. Long, Jean-François Lamarque, Alfonso Saiz-Lopez, Kathryn McKain, Colm Sweeney, Alan J. Hills, and Eric C. Apel
Atmos. Chem. Phys., 19, 14071–14090,Short summary
Halogenated organic trace gases, which are a source of reactive halogens to the atmosphere, exert a disproportionately large influence on atmospheric chemistry and climate. This paper reports novel aircraft observations of halogenated compounds over the Southern Ocean in summer and evaluates hypothesized regional sources and emissions of these trace gases through their relationships to additional aircraft observations.
Marianne T. Lund, Gunnar Myhre, and Bjørn H. Samset
Atmos. Chem. Phys., 19, 13827–13839,Short summary
Atmospheric aerosols play an integral role in shaping local and global climate by modifying the energy balance, clouds and precipitation. They are also a leading cause of premature mortality in many areas. New scenarios provide projections of emissions until 2100 given strong, medium or weak air pollution control stringency. We quantify the consequent regional and global aerosol loading and radiative forcing, showing a large spread at the end of the century and regional differences in trends.
Jie Li, Tatsuya Nagashima, Lei Kong, Baozhu Ge, Kazuyo Yamaji, Joshua S. Fu, Xuemei Wang, Qi Fan, Syuichi Itahashi, Hyo-Jung Lee, Cheol-Hee Kim, Chuan-Yao Lin, Meigen Zhang, Zhining Tao, Mizuo Kajino, Hong Liao, Meng Li, Jung-Hun Woo, Jun-ichi Kurokawa, Zhe Wang, Qizhong Wu, Hajime Akimoto, Gregory R. Carmichael, and Zifa Wang
Atmos. Chem. Phys., 19, 12993–13015,Short summary
This study evaluated and intercompared 14 CTMs with ozone observations in East Asia, within the framework of the Model Inter-Comparison Study for ASIA Phase III (MICS-Asia III). Potential causes of the discrepancies between model results and observation were investigated by assessing the planetary boundary layer heights, emission fluxes, dry deposition, chemistry and vertical transport among models. Finally, a multi-model estimate of pollution distributions was provided.
Øivind Hodnebrog, Gunnar Myhre, Bjørn H. Samset, Kari Alterskjær, Timothy Andrews, Olivier Boucher, Gregory Faluvegi, Dagmar Fläschner, Piers M. Forster, Matthew Kasoar, Alf Kirkevåg, Jean-Francois Lamarque, Dirk Olivié, Thomas B. Richardson, Dilshad Shawki, Drew Shindell, Keith P. Shine, Philip Stier, Toshihiko Takemura, Apostolos Voulgarakis, and Duncan Watson-Parris
Atmos. Chem. Phys., 19, 12887–12899,Short summary
Different greenhouse gases (e.g. CO2) and aerosols (e.g. black carbon) impact the Earth’s water cycle differently. Here we investigate how various gases and particles impact atmospheric water vapour and its lifetime, i.e., the average number of days that water vapour stays in the atmosphere after evaporation and before precipitation. We find that this lifetime could increase substantially by the end of this century, indicating that important changes in precipitation patterns are excepted.
Dominic A. Winski, Tyler J. Fudge, David G. Ferris, Erich C. Osterberg, John M. Fegyveresi, Jihong Cole-Dai, Zayta Thundercloud, Thomas S. Cox, Karl J. Kreutz, Nikolas Ortman, Christo Buizert, Jenna Epifanio, Edward J. Brook, Ross Beaudette, Jeffrey Severinghaus, Todd Sowers, Eric J. Steig, Emma C. Kahle, Tyler R. Jones, Valerie Morris, Murat Aydin, Melinda R. Nicewonger, Kimberly A. Casey, Richard B. Alley, Edwin D. Waddington, Nels A. Iverson, Nelia W. Dunbar, Ryan C. Bay, Joseph M. Souney, Michael Sigl, and Joseph R. McConnell
Clim. Past, 15, 1793–1808,Short summary
A deep ice core was recently drilled at the South Pole to understand past variations in the Earth's climate. To understand the information contained within the ice, we present the relationship between the depth and age of the ice in the South Pole Ice Core. We found that the oldest ice in our record is from 54 302 ± 519 years ago. Our results show that, on average, 7.4 cm of snow falls at the South Pole each year.
Lei Chen, Yi Gao, Meigen Zhang, Joshua S. Fu, Jia Zhu, Hong Liao, Jialin Li, Kan Huang, Baozhu Ge, Xuemei Wang, Yun Fat Lam, Chuan-Yao Lin, Syuichi Itahashi, Tatsuya Nagashima, Mizuo Kajino, Kazuyo Yamaji, Zifa Wang, and Jun-ichi Kurokawa
Atmos. Chem. Phys., 19, 11911–11937,Short summary
Simulated aerosol concentrations from 14 CTMs within the framework of MICS-Asia III are detailedly evaluated with an extensive set of measurements in East Asia. Similarities and differences among model performances are also analyzed. Although more considerable capacities for reproducing the aerosol concentrations and their variations are shown in current CTMs than those in MICS-Asia II, more efforts are needed to reduce diversities of simulated aerosol concentrations among air quality models.
Cheng Dang, Charles S. Zender, and Mark G. Flanner
The Cryosphere, 13, 2325–2343,
Meng Wang, Ru-Jin Huang, Junji Cao, Wenting Dai, Jiamao Zhou, Chunshui Lin, Haiyan Ni, Jing Duan, Ting Wang, Yang Chen, Yongjie Li, Qi Chen, Imad El Haddad, and Thorsten Hoffmann
Atmos. Meas. Tech., 12, 4779–4789,Short summary
The analytical performances of SE-GC-MS and TD-GC-MS for the determination of n-alkanes, PAHs and hopanes were evaluated and compared. The two methods show a good agreement with a high correlation efficient (R2 > 0.98) and a slope close to unity. The concentrations of n-alkanes, PAHs and hopanes are found to be much higher in Beijing than those in Chengdu, Shanghai and Guangzhou, most likely due to emissions from coal combustion for wintertime heating in Beijing.
Haiyan Ni, Ru-Jin Huang, Junji Cao, Wenting Dai, Jiamao Zhou, Haoyue Deng, Anita Aerts-Bijma, Harro A. J. Meijer, and Ulrike Dusek
Atmos. Chem. Phys., 19, 10405–10422,Short summary
We apply radiocarbon source apportionment of more volatile organic carbon (mvOC) to winter aerosol samples from six Chinese cities. We find a consistently larger contribution of fossil sources to mvOC than to secondary or total organic carbon. Fossil mvOC concentrations are strongly correlated with primary fossil OC but not with secondary fossil OC. The variability in nonfossil mvOC seems to be related to both primary and secondary biomass burning sources.
Jing Duan, Ru-Jin Huang, Chunshui Lin, Wenting Dai, Meng Wang, Yifang Gu, Ying Wang, Haobin Zhong, Yan Zheng, Haiyan Ni, Uli Dusek, Yang Chen, Yongjie Li, Qi Chen, Douglas R. Worsnop, Colin D. O'Dowd, and Junji Cao
Atmos. Chem. Phys., 19, 10319–10334,Short summary
We present the seasonal distinction of secondary aerosol formation in urban Beijing. Both photochemical oxidation and aqueous-phase processing played important roles in SOA (secondary organic aerosol) formation during all three seasons; while for sulfate formation, gas-phase photochemical oxidation was the major pathway in late summer, aqueous-phase reactions were more responsible during early winter, and both processes had contributions during autumn.
Kévin Lamy, Thierry Portafaix, Béatrice Josse, Colette Brogniez, Sophie Godin-Beekmann, Hassan Bencherif, Laura Revell, Hideharu Akiyoshi, Slimane Bekki, Michaela I. Hegglin, Patrick Jöckel, Oliver Kirner, Ben Liley, Virginie Marecal, Olaf Morgenstern, Andrea Stenke, Guang Zeng, N. Luke Abraham, Alexander T. Archibald, Neil Butchart, Martyn P. Chipperfield, Glauco Di Genova, Makoto Deushi, Sandip S. Dhomse, Rong-Ming Hu, Douglas Kinnison, Michael Kotkamp, Richard McKenzie, Martine Michou, Fiona M. O'Connor, Luke D. Oman, Giovanni Pitari, David A. Plummer, John A. Pyle, Eugene Rozanov, David Saint-Martin, Kengo Sudo, Taichu Y. Tanaka, Daniele Visioni, and Kohei Yoshida
Atmos. Chem. Phys., 19, 10087–10110,Short summary
In this study, we simulate the ultraviolet radiation evolution during the 21st century on Earth's surface using the output from several numerical models which participated in the Chemistry-Climate Model Initiative. We present four possible futures which depend on greenhouse gases emissions. The role of ozone-depleting substances, greenhouse gases and aerosols are investigated. Our results emphasize the important role of aerosols for future ultraviolet radiation in the Northern Hemisphere.
James A. Menking, Edward J. Brook, Sarah A. Shackleton, Jeffrey P. Severinghaus, Michael N. Dyonisius, Vasilii Petrenko, Joseph R. McConnell, Rachael H. Rhodes, Thomas K. Bauska, Daniel Baggenstos, Shaun Marcott, and Stephen Barker
Clim. Past, 15, 1537–1556,Short summary
An ice core from Taylor Glacier, Antarctica, spans a period ~ 70 000 years ago when Earth entered the last ice age. Chemical analyses of the ice and air bubbles allow for an independent determination of the ages of the ice and gas bubbles. The difference between the age of the ice and the bubbles at any given depth, called ∆age, is unusually high in the Taylor Glacier core compared to the Taylor Dome ice core situated to the south. This implies a dramatic accumulation gradient between the sites.
Christoph Heinze, Veronika Eyring, Pierre Friedlingstein, Colin Jones, Yves Balkanski, William Collins, Thierry Fichefet, Shuang Gao, Alex Hall, Detelina Ivanova, Wolfgang Knorr, Reto Knutti, Alexander Löw, Michael Ponater, Martin G. Schultz, Michael Schulz, Pier Siebesma, Joao Teixeira, George Tselioudis, and Martin Vancoppenolle
Earth Syst. Dynam., 10, 379–452,Short summary
Earth system models for producing climate projections under given forcings include additional processes and feedbacks that traditional physical climate models do not consider. We present an overview of climate feedbacks for key Earth system components and discuss the evaluation of these feedbacks. The target group for this article includes generalists with a background in natural sciences and an interest in climate change as well as experts working in interdisciplinary climate research.
Jiarui Wu, Naifang Bei, Bo Hu, Suixin Liu, Meng Zhou, Qiyuan Wang, Xia Li, Lang Liu, Tian Feng, Zirui Liu, Yichen Wang, Junji Cao, Xuexi Tie, Jun Wang, Luisa T. Molina, and Guohui Li
Atmos. Chem. Phys., 19, 8703–8719,Short summary
In the present study, simulations during a persistent and heavy haze pollution episode from 5 December 2015 to 4 January 2016 in the North China Plain (NCP) were performed using the WRF-Chem model to comprehensively quantify contributions of the aerosol shortwave radiative feedback (ARF) to near-surface PM2.5 mass concentrations. During the episode, the ARF deteriorates the haze pollution, increasing the near-surface PM2.5 concentration in the NCP by 10.2 μg m−3 (7.8 %) on average.
Jiarui Wu, Naifang Bei, Bo Hu, Suixin Liu, Meng Zhou, Qiyuan Wang, Xia Li, Lang Liu, Tian Feng, Zirui Liu, Yichen Wang, Junji Cao, Xuexi Tie, Jun Wang, Luisa T. Molina, and Guohui Li
Atmos. Chem. Phys., 19, 8721–8739,Short summary
The near-surface PM2.5 contribution of the ALW total effect is 17.5 % in NCP, indicating that ALW plays an important role in the PM2.5 formation during the wintertime haze pollution. Moreover, the ALW-HET overwhelmingly dominates the PM2.5 enhancement due to the ALW. The ALW does not consistently enhance near-surface [PM2.5] with increasing RH. When the RH exceeds 80 %, the contribution of the ALW begins to decrease, which is caused by the high occurrence frequencies of precipitation.
Hiroaki Tatebe, Tomoo Ogura, Tomoko Nitta, Yoshiki Komuro, Koji Ogochi, Toshihiko Takemura, Kengo Sudo, Miho Sekiguchi, Manabu Abe, Fuyuki Saito, Minoru Chikira, Shingo Watanabe, Masato Mori, Nagio Hirota, Yoshio Kawatani, Takashi Mochizuki, Kei Yoshimura, Kumiko Takata, Ryouta O'ishi, Dai Yamazaki, Tatsuo Suzuki, Masao Kurogi, Takahito Kataoka, Masahiro Watanabe, and Masahide Kimoto
Geosci. Model Dev., 12, 2727–2765,Short summary
For a deeper understanding of a wide range of climate science issues, the latest version of the Japanese climate model, called MIROC6, was developed. The climate model represents observed mean climate and climate variations well, for example tropical precipitation, the midlatitude westerlies, and the East Asian monsoon, which influence human activity all over the world. The improved climate simulations could add reliability to climate predictions under global warming.
Jun Tao, Zhisheng Zhang, Yunfei Wu, Leiming Zhang, Zhijun Wu, Peng Cheng, Mei Li, Laiguo Chen, Renjian Zhang, and Junji Cao
Atmos. Chem. Phys., 19, 8471–8490,Short summary
Mass-scattering efficiencies (MSE) of dominant chemical species in atmospheric aerosols are important parameters for building the relationships between chemical species and the particle-scattering coefficient. Particle MSE mainly depends on the mass fractions of (NH4)2SO4, NH4NO3, and organic matter and their MSEs in the droplet mode. MSEs of (NH4)2SO4, NH4NO3 and organic matter were determined by their size distributions in the droplet mode.
Adam Schneider, Mark Flanner, Roger De Roo, and Alden Adolph
The Cryosphere, 13, 1753–1766,Short summary
To study the process of snow aging, we engineered a prototype instrument called the Near-Infrared Emitting and Reflectance-Monitoring Dome (NERD). Using the NERD, we observed rapid snow aging in experiments with added light absorbing particles (LAPs). Particulate matter deposited on the snow increased absorption of solar energy and enhanced snow melt. These results indicate the role of LAPs' indirect effect on snow aging through a positive feedback mechanism related to the snow grain size.
Keiichiro Hara, Kengo Sudo, Takato Ohnishi, Kazuo Osada, Masanori Yabuki, Masataka Shiobara, and Takashi Yamanouchi
Atmos. Chem. Phys., 19, 7817–7837,Short summary
We measured equivalent black carbon (EBC) concentrations at Syowa Station, Antarctica, from February 2005. EBC might be transported directly to Syowa Station from mid-latitudes mainly via the boundary layer and the lower free troposphere. Some BC was transported to Antarctic regions via the upper free troposphere. Biomass burning in South America and southern Africa is the most dominant source. Fossil fuel combustion in South America and southern Africa also have important contributions.
Tian Feng, Shuyu Zhao, Naifang Bei, Jiarui Wu, Suixin Liu, Xia Li, Lang Liu, Yang Qian, Qingchuan Yang, Yichen Wang, Weijian Zhou, Junji Cao, and Guohui Li
Atmos. Chem. Phys., 19, 7429–7443,Short summary
The observed ratio of organic carbon to element carbon has increased remarkably in Beijing. Here, based on the measurements and model simulation, we show that the enhanced atmospheric oxidizing capacity is an important contributor to that increase by facilitating the aging process of organic aerosols (add oxygen). Our results indicate a ubiquitous enhancement of secondary organic aerosol formation over Beijing–Tianjin–Hebei, China, in the context of increasing oxidizing capacity.
Yugo Kanaya, Kazuyuki Miyazaki, Fumikazu Taketani, Takuma Miyakawa, Hisahiro Takashima, Yuichi Komazaki, Xiaole Pan, Saki Kato, Kengo Sudo, Takashi Sekiya, Jun Inoue, Kazutoshi Sato, and Kazuhiro Oshima
Atmos. Chem. Phys., 19, 7233–7254,Short summary
Ozone and carbon monoxide levels were uniquely observed (for > 10 000 h) over oceans from 67° S to 75° N. Tropospheric chemistry reanalysis v2 reproduced the observed evolution of pollution plumes from continents but underpredicted and overpredicted ozone levels in the Arctic and in the western Pacific equatorial region, respectively. Processes to explain the gaps are proposed, including halogen-mediated destruction in the low latitudes. Our open data set will complement the TOAR data collection.
Hongmei Xu, Jean-François Léon, Cathy Liousse, Benjamin Guinot, Véronique Yoboué, Aristide Barthélémy Akpo, Jacques Adon, Kin Fai Ho, Steven Sai Hang Ho, Lijuan Li, Eric Gardrat, Zhenxing Shen, and Junji Cao
Atmos. Chem. Phys., 19, 6637–6657,Short summary
This paper discusses the personal exposure characteristics and health implication of PM2.5 and bounded chemical species based on three anthropogenic sources and related populations (domestic fires for women, waste burning for students and motorcycle traffic for drivers) in Abidjan and Cotonou in dry and wet seasons of 2016. This work can be regarded as the first attempt at measuring personal exposure to PM2.5 and its related health risks in underdeveloped countries of Africa.
Zainab Q. Hakim, Scott Archer-Nicholls, Gufran Beig, Gerd A. Folberth, Kengo Sudo, Nathan Luke Abraham, Sachin Ghude, Daven K. Henze, and Alexander T. Archibald
Atmos. Chem. Phys., 19, 6437–6458,Short summary
Surface ozone is an important air pollutant and recent work has calculated that large numbers of people die prematurely because of exposure to high levels of surface ozone in India. However, these calculations require model simulations of ozone as key inputs. Here we perform the most thorough evaluation of global model surface ozone over India to date. These analyses of model simulations and observations highlight some successes and shortcomings and the need for further process-based studies.
Huang Yang, Darryn W. Waugh, Clara Orbe, Guang Zeng, Olaf Morgenstern, Douglas E. Kinnison, Jean-Francois Lamarque, Simone Tilmes, David A. Plummer, Patrick Jöckel, Susan E. Strahan, Kane A. Stone, and Robyn Schofield
Atmos. Chem. Phys., 19, 5511–5528,Short summary
We evaluate the performance of a suite of models in simulating the large-scale transport from the northern midlatitudes to the Arctic using a CO-like idealized tracer. We find a large multi-model spread of the Arctic concentration of this CO-like tracer that is well correlated with the differences in the location of the midlatitude jet as well as the northern Hadley Cell edge. Our results suggest the Hadley Cell is key and zonal-mean transport by surface meridional flow needs better constraint.
Mai Winstrup, Paul Vallelonga, Helle A. Kjær, Tyler J. Fudge, James E. Lee, Marie H. Riis, Ross Edwards, Nancy A. N. Bertler, Thomas Blunier, Ed J. Brook, Christo Buizert, Gabriela Ciobanu, Howard Conway, Dorthe Dahl-Jensen, Aja Ellis, B. Daniel Emanuelsson, Richard C. A. Hindmarsh, Elizabeth D. Keller, Andrei V. Kurbatov, Paul A. Mayewski, Peter D. Neff, Rebecca L. Pyne, Marius F. Simonsen, Anders Svensson, Andrea Tuohy, Edwin D. Waddington, and Sarah Wheatley
Clim. Past, 15, 751–779,Short summary
We present a 2700-year timescale and snow accumulation history for an ice core from Roosevelt Island, Ross Ice Shelf, Antarctica. We observe a long-term slightly decreasing trend in accumulation during most of the period but a rapid decline since the mid-1960s. The latter is linked to a recent strengthening of the Amundsen Sea Low and the expansion of regional sea ice. The year 1965 CE may thus mark the onset of significant increases in sea-ice extent in the eastern Ross Sea.
Moa K. Sporre, Sara M. Blichner, Inger H. H. Karset, Risto Makkonen, and Terje K. Berntsen
Atmos. Chem. Phys., 19, 4763–4782,Short summary
In this study, an Earth system model has been used to investigate climate feedbacks associated with increasing BVOC emissions due to higher CO2 concentrations and temperatures. Higher BVOC emissions associated with a changed climate are found to induce an important negative climate feedback through increased aerosol formation and resulting changes in cloud properties. This feedback is found to have the potential to offset about 13 % of the radiative forcing associated with a doubling of CO2.
Long Chen, Yu Huang, Yonggang Xue, Zhenxing Shen, Junji Cao, and Wenliang Wang
Atmos. Chem. Phys., 19, 4075–4091,Short summary
The present calculations show that the sequential addition of CIs to HHPs affords oligomers containing CIs as chain units. The addition of an –OOH group in HHPs to the central carbon atom of CIs is identified as the most energetically favorable channel, with a barrier height strongly dependent on both CI substituent number (one or two) and position (syn- or anti-). In particular, the introduction of a methyl group into the anti-position significantly increases the rate coefficient.
Yang Chen, Mi Tian, Ru-Jin Huang, Guangming Shi, Huanbo Wang, Chao Peng, Junji Cao, Qiyuan Wang, Shumin Zhang, Dongmei Guo, Leiming Zhang, and Fumo Yang
Atmos. Chem. Phys., 19, 3245–3255,Short summary
Amine-containing particles were characterized in an urban area of Chongqing during both summer and winter using a single-particle aerosol mass spectrometer (SPAMS). Amines were observed to internally mix with elemental carbon (EC), organic carbon (OC), sulfate, and nitrate. Diethylamine (DEA) was the most abundant in both number and peak area among amine-containing particles. Vegetation and traffic were the primary sources of particulate amines.
Kai-Lan Chang, Owen R. Cooper, J. Jason West, Marc L. Serre, Martin G. Schultz, Meiyun Lin, Virginie Marécal, Béatrice Josse, Makoto Deushi, Kengo Sudo, Junhua Liu, and Christoph A. Keller
Geosci. Model Dev., 12, 955–978,Short summary
We developed a new method for combining surface ozone observations from thousands of monitoring sites worldwide with the output from multiple atmospheric chemistry models. The result is a global surface ozone distribution with greater accuracy than any single model can achieve. We focused on an ozone metric relevant to human mortality caused by long-term ozone exposure. Our method can be applied to studies that quantify the impacts of ozone on human health and mortality.
Sauvik Santra, Shubha Verma, Koji Fujita, Indrajit Chakraborty, Olivier Boucher, Toshihiko Takemura, John F. Burkhart, Felix Matt, and Mukesh Sharma
Atmos. Chem. Phys., 19, 2441–2460,Short summary
The present study provided information on specific glaciers over the Hindu Kush Himalayan region identified as being vulnerable to BC-induced impacts (affected by high BC-induced snow albedo reduction in addition to being sensitive to BC-induced impacts), thus impacting the downstream hydrology. The source-specific contribution to atmospheric BC aerosols by emission sources led to identifying the potential emission source, which was distinctive over south and north to 30° N.
Anna Lewinschal, Annica M. L. Ekman, Hans-Christen Hansson, Maria Sand, Terje K. Berntsen, and Joakim Langner
Atmos. Chem. Phys., 19, 2385–2403,Short summary
We use a global climate model to study how anthropogenic emissions of short-lived atmospheric particles in different parts of the world influence the global temperature distribution. We find that the global mean temperature change per unit emission is similar for all emission regions, and the largest temperature response is found in the Arctic no matter where the emissions occur. However, for European emissions, the temperature change per unit emission is found to depend on emission strength.
Ru-Jin Huang, Yichen Wang, Junji Cao, Chunshui Lin, Jing Duan, Qi Chen, Yongjie Li, Yifang Gu, Jin Yan, Wei Xu, Roman Fröhlich, Francesco Canonaco, Carlo Bozzetti, Jurgita Ovadnevaite, Darius Ceburnis, Manjula R. Canagaratna, John Jayne, Douglas R. Worsnop, Imad El-Haddad, André S. H. Prévôt, and Colin D. O'Dowd
Atmos. Chem. Phys., 19, 2283–2298,Short summary
We found that in wintertime Shijiazhuang fine PM was mostly from primary emissions without sufficient atmospheric aging. In addition, secondary inorganic and organic aerosol dominated in pollution events under high-RH conditions, likely due to enhanced aqueous-phase chemistry, whereas primary organic aerosol dominated in pollution events under low-RH and stagnant conditions. Our results also highlighted the importance of meteorological conditions for PM pollution in this highly polluted city.
Kjetil S. Aas, Léo Martin, Jan Nitzbon, Moritz Langer, Julia Boike, Hanna Lee, Terje K. Berntsen, and Sebastian Westermann
The Cryosphere, 13, 591–609,Short summary
Many permafrost landscapes contain large amounts of excess ground ice, which gives rise to small-scale elevation differences. This results in lateral fluxes of snow, water, and heat, which we investigate and show how it can be accounted for in large-scale models. Using a novel model technique which can account for these differences, we are able to model both the current state of permafrost and how these landscapes change as permafrost thaws, in a way that could not previously be achieved.
Qiyuan Wang, Suixin Liu, Nan Li, Wenting Dai, Yunfei Wu, Jie Tian, Yaqing Zhou, Meng Wang, Steven Sai Hang Ho, Yang Chen, Renjian Zhang, Shuyu Zhao, Chongshu Zhu, Yongming Han, Xuexi Tie, and Junji Cao
Atmos. Chem. Phys., 19, 1881–1899,
Junxi Zhang, Yang Gao, L. Ruby Leung, Kun Luo, Huan Liu, Jean-Francois Lamarque, Jianren Fan, Xiaohong Yao, Huiwang Gao, and Tatsuya Nagashima
Atmos. Chem. Phys., 19, 887–900,Short summary
ACCMIP simulations were used to study NOy deposition over East Asia in the future. Both dry and wet NOy deposition show significant decreases in the 2100s under RCP4.5 and RCP8.5 due to large anthropogenic emission reduction. The changes in climate only significantly affect the wet deposition primarily linked to changes in precipitation. Over the coastal seas of China, weaker transport of NOy from land due to emission reduction infers a larger impact from shipping and lightning emissions.
Hajime Akimoto, Tatsuya Nagashima, Jie Li, Joshua S. Fu, Dongsheng Ji, Jiani Tan, and Zifa Wang
Atmos. Chem. Phys., 19, 603–615,Short summary
The regional model intercomparison study called MICS-Asia III revealed that substantial discrepancy still exists for surface ozone simulation in East Asia, even though common emissions, meteorological field, and boundary conditions have been used among the models. Three factors have been identified as possible causes of such discrepancy, (1) chemistry sub-models, (2) heterogeneous reactions, and (3) vertical transport parameters, and each component has been discussed.
Fabien Paulot, Sergey Malyshev, Tran Nguyen, John D. Crounse, Elena Shevliakova, and Larry W. Horowitz
Atmos. Chem. Phys., 18, 17963–17978,
Gerhard Krinner, Chris Derksen, Richard Essery, Mark Flanner, Stefan Hagemann, Martyn Clark, Alex Hall, Helmut Rott, Claire Brutel-Vuilmet, Hyungjun Kim, Cécile B. Ménard, Lawrence Mudryk, Chad Thackeray, Libo Wang, Gabriele Arduini, Gianpaolo Balsamo, Paul Bartlett, Julia Boike, Aaron Boone, Frédérique Chéruy, Jeanne Colin, Matthias Cuntz, Yongjiu Dai, Bertrand Decharme, Jeff Derry, Agnès Ducharne, Emanuel Dutra, Xing Fang, Charles Fierz, Josephine Ghattas, Yeugeniy Gusev, Vanessa Haverd, Anna Kontu, Matthieu Lafaysse, Rachel Law, Dave Lawrence, Weiping Li, Thomas Marke, Danny Marks, Martin Ménégoz, Olga Nasonova, Tomoko Nitta, Masashi Niwano, John Pomeroy, Mark S. Raleigh, Gerd Schaedler, Vladimir Semenov, Tanya G. Smirnova, Tobias Stacke, Ulrich Strasser, Sean Svenson, Dmitry Turkov, Tao Wang, Nander Wever, Hua Yuan, Wenyan Zhou, and Dan Zhu
Geosci. Model Dev., 11, 5027–5049,Short summary
This paper provides an overview of a coordinated international experiment to determine the strengths and weaknesses in how climate models treat snow. The models will be assessed at point locations using high-quality reference measurements and globally using satellite-derived datasets. How well climate models simulate snow-related processes is important because changing snow cover is an important part of the global climate system and provides an important freshwater resource for human use.
Marianne Tronstad Lund, Gunnar Myhre, Amund Søvde Haslerud, Ragnhild Bieltvedt Skeie, Jan Griesfeller, Stephen Matthew Platt, Rajesh Kumar, Cathrine Lund Myhre, and Michael Schulz
Geosci. Model Dev., 11, 4909–4931,Short summary
Atmospheric aerosols play a key role in the climate system, but their exact impact on the energy balance remains uncertain. Accurate representation of the geographical distribution and properties of aerosols in global models is key to reduce this uncertainty. Here we use a new emission inventory and a range of observations to carefully validate a state-of-the-art model and present an updated estimate of the net direct effect of anthropogenic aerosols since the preindustrial era.
Samuel R. Hall, Kirk Ullmann, Michael J. Prather, Clare M. Flynn, Lee T. Murray, Arlene M. Fiore, Gustavo Correa, Sarah A. Strode, Stephen D. Steenrod, Jean-Francois Lamarque, Jonathan Guth, Béatrice Josse, Johannes Flemming, Vincent Huijnen, N. Luke Abraham, and Alex T. Archibald
Atmos. Chem. Phys., 18, 16809–16828,Short summary
Photolysis (J rates) initiates and drives atmospheric chemistry, and Js are perturbed by factors of 2 by clouds. The NASA Atmospheric Tomography (ATom) Mission provides the first comprehensive observations on how clouds perturb Js through the remote Pacific and Atlantic basins. We compare these cloud-perturbation J statistics with those from nine global chemistry models. While basic patterns agree, there is a large spread across models, and all lack some basic features of the observations.
Haiyan Ni, Ru-Jin Huang, Junji Cao, Weiguo Liu, Ting Zhang, Meng Wang, Harro A. J. Meijer, and Ulrike Dusek
Atmos. Chem. Phys., 18, 16363–16383,Short summary
Seasonal changes in organic carbon (OC) and elemental carbon (EC) sources in Xi'an, China, are investigated based on measurements of radiocarbon and the stable isotope 13C. Relative contributions to EC from biomass burning, coal combustion, and vehicle emissions change substantially between different seasons. Biomass burning contributes 60 % to the EC increment in winter. Comparing concentrations and sources of primary OC to total OC suggests non-negligible OC loss due to active photochemistry.
Yang Li and Mark G. Flanner
Atmos. Chem. Phys., 18, 16005–16018,Short summary
Light-absorbing impurities enhance snowmelt by boosting the absorption of solar energy. It is therefore important for coupled aerosol–climate and ice sheet models to include this effect, and yet most do not. We conduct several thousand simulations and develop a kernel and linear equations relating melt runoff on the Greenland Ice Sheet to the timing and amount of black carbon within precipitation and dry deposition, which can be used to extend the utility of state-of-the-art aerosol models.
Mackenzie M. Grieman, Murat Aydin, Joseph R. McConnell, and Eric S. Saltzman
Clim. Past, 14, 1625–1637,Short summary
Vanillic acid is reported in the Tunu ice core from northeastern Greenland. It is an aerosol-borne acid produced by biomass burning. North American boreal forests are likely the source regions of the vanillic acid deposited at the ice core site. Vanillic acid levels were elevated during warm climate periods and lower during cooler climate periods. There is a positive correlation between the vanillic acid ice core record and ammonium and black carbon in the NEEM ice core from northern Greenland.
Rumi Ohgaito, Ayako Abe-Ouchi, Ryouta O'ishi, Toshihiko Takemura, Akinori Ito, Tomohiro Hajima, Shingo Watanabe, and Michio Kawamiya
Clim. Past, 14, 1565–1581,Short summary
The behaviour of dust in terms of climate can be investigated using past climate. The Last Glacial Maximum (LGM; 21000 years before present) is known to be dustier. We investigated the impact of plausible dust distribution on the climate of the LGM using an Earth system model and found that the higher dust load results in less cooling over the polar regions. The main finding is that radiative perturbation by the high dust loading does not necessarily cool the surface surrounding Antarctica.
Ilissa B. Ocko, Vaishali Naik, and David Paynter
Atmos. Chem. Phys., 18, 15555–15568,Short summary
As communities worldwide analyse options to reduce methane emissions from energy use, agriculture, and waste management, there is an immediate need to build confidence in rapid assessment tools other than standard climate metrics – which misrepresent impacts over all timescales. In this paper, we show that a simplified climate model can easily and rapidly provide scientifically robust climate responses to changes in methane emissions, thereby improving mitigation analysis and decision-making.
Xinyi Dong, Joshua S. Fu, Qingzhao Zhu, Jian Sun, Jiani Tan, Terry Keating, Takashi Sekiya, Kengo Sudo, Louisa Emmons, Simone Tilmes, Jan Eiof Jonson, Michael Schulz, Huisheng Bian, Mian Chin, Yanko Davila, Daven Henze, Toshihiko Takemura, Anna Maria Katarina Benedictow, and Kan Huang
Atmos. Chem. Phys., 18, 15581–15600,Short summary
We have applied the HTAP phase II multi-model data to investigate the long-range transport impacts on surface concentration and column density of PM from Europe and Russia, Belarus, and Ukraine to eastern Asia, with a special focus on the long-range transport contribution during haze episodes in China. We found that long-range transport plays a more important role in elevating the background concentration of surface PM during the haze days.
Arlene M. Fiore, Emily V. Fischer, George P. Milly, Shubha Pandey Deolal, Oliver Wild, Daniel A. Jaffe, Johannes Staehelin, Olivia E. Clifton, Dan Bergmann, William Collins, Frank Dentener, Ruth M. Doherty, Bryan N. Duncan, Bernd Fischer, Stefan Gilge, Peter G. Hess, Larry W. Horowitz, Alexandru Lupu, Ian A. MacKenzie, Rokjin Park, Ludwig Ries, Michael G. Sanderson, Martin G. Schultz, Drew T. Shindell, Martin Steinbacher, David S. Stevenson, Sophie Szopa, Christoph Zellweger, and Guang Zeng
Atmos. Chem. Phys., 18, 15345–15361,Short summary
We demonstrate a proof-of-concept approach for applying northern midlatitude mountaintop peroxy acetyl nitrate (PAN) measurements and a multi-model ensemble during April to constrain the influence of continental-scale anthropogenic precursor emissions on PAN. Our findings imply a role for carefully coordinated multi-model ensembles in helping identify observations for discriminating among widely varying (and poorly constrained) model responses of atmospheric constituents to changes in emissions.
Jingjing Meng, Gehui Wang, Zhanfang Hou, Xiaodi Liu, Benjie Wei, Can Wu, Cong Cao, Jiayuan Wang, Jianjun Li, Junji Cao, Erxun Zhang, Jie Dong, Jiazhen Liu, Shuangshuang Ge, and Yuning Xie
Atmos. Chem. Phys., 18, 15069–15086,
Benjamin Brown-Steiner, Noelle E. Selin, Ronald Prinn, Simone Tilmes, Louisa Emmons, Jean-François Lamarque, and Philip Cameron-Smith
Geosci. Model Dev., 11, 4155–4174,Short summary
We conduct three simulations of atmospheric chemistry using chemical mechanisms of different levels of complexity and compare their results to observations. We explore situations in which the simplified mechanisms match the output of the most complex mechanism, as well as when they diverge. We investigate how concurrent utilization of chemical mechanisms of different complexities can further our atmospheric-chemistry understanding at various scales and give some strategies for future research.
Jan Eiof Jonson, Michael Schulz, Louisa Emmons, Johannes Flemming, Daven Henze, Kengo Sudo, Marianne Tronstad Lund, Meiyun Lin, Anna Benedictow, Brigitte Koffi, Frank Dentener, Terry Keating, Rigel Kivi, and Yanko Davila
Atmos. Chem. Phys., 18, 13655–13672,Short summary
Focusing on Europe, this HTAP 2 study computes ozone in several global models when reducing anthropogenic emissions by 20 % in different world regions. The differences in model results are explored by use of a novel stepwise approach combining a tracer, CO and ozone. For ozone the contributions from the rest of the world are larger than from Europe, with the largest contributions from North America and eastern Asia. Contributions do, however, depend on the choice of ozone metric.
Jiamao Zhou, Xuexi Tie, Baiqing Xu, Shuyu Zhao, Mo Wang, Guohui Li, Ting Zhang, Zhuzi Zhao, Suixin Liu, Song Yang, Luyu Chang, and Junji Cao
Atmos. Chem. Phys., 18, 13673–13685,Short summary
A global chemical transportation model (MOZART-4) was used to analyze the BC transport from the source regions and a radiative transfer model (SNICAR) was used to study the effect of BC on snow albedo on the northern Tibetan Plateau. The result provides useful information to study the effect of the upward BC emissions on environmental and climate issues. The radiative effect of BC deposition on the snow melting provides important information regarding the water resources in the region.
Fabien Paulot, David Paynter, Paul Ginoux, Vaishali Naik, and Larry W. Horowitz
Atmos. Chem. Phys., 18, 13265–13281,Short summary
Observations show that the sunlight reflected to space by particles has decreased over the US and Europe, increased over India, and not changed over China from 2001 to 2015. These changes are attributed to different types of particles, namely sulfate over the US and Europe, and black carbon, sulfate, and nitrate over China and India. Our results suggest that the recent shift in human emissions from the US and Europe to Asia has altered their impact on the Earth's outgoing energy.
Daniel M. Westervelt, Andrew J. Conley, Arlene M. Fiore, Jean-François Lamarque, Drew T. Shindell, Michael Previdi, Nora R. Mascioli, Greg Faluvegi, Gustavo Correa, and Larry W. Horowitz
Atmos. Chem. Phys., 18, 12461–12475,Short summary
Small particles in Earth's atmosphere (also referred to as atmospheric aerosols) emitted by human activities impact Earth's climate in complex ways and play an important role in Earth's water cycle. We use a climate modeling approach and find that aerosols from the United States and Europe can have substantial effects on rainfall in far-away regions such as Africa's Sahel or the Mediterranean. Air pollution controls in these regions may help reduce the likelihood and severity of Sahel drought.
Christian M. Zdanowicz, Bernadette C. Proemse, Ross Edwards, Wang Feiteng, Chad M. Hogan, Christophe Kinnard, and David Fisher
Atmos. Chem. Phys., 18, 12345–12361,Short summary
Black carbon (BC) particles emitted by natural and anthropogenic sources (e.g., wildfires, coal burning) can amplify climate warming by increasing sunlight energy absorption on snow-covered surfaces. This paper presents a new ice-core record of historical (1810–1990) BC deposition in the Canadian Arctic. The Devon ice cap record differs from Greenland ice cores, implying large variations in BC deposition across the Arctic that must be accounted for to better quantity their future climate impact.
Jiani Tan, Joshua S. Fu, Frank Dentener, Jian Sun, Louisa Emmons, Simone Tilmes, Johannes Flemming, Toshihiko Takemura, Huisheng Bian, Qingzhao Zhu, Cheng-En Yang, and Terry Keating
Atmos. Chem. Phys., 18, 12223–12240,Short summary
Have contributions of hemispheric air pollution to deposition at global scale been overlooked in the past years? How do we assess the critical load for the acid deposition when we look for the demand of forest and crop? This study highlights the significant impact of hemispheric transport on deposition in coastal regions, open ocean and low-emission regions. Further research is proposed for improving ecosystem and human health in these regions, with regards to the enhanced hemispheric transport.
Pakawat Phalitnonkiat, Peter G. M. Hess, Mircea D. Grigoriu, Gennady Samorodnitsky, Wenxiu Sun, Ellie Beaudry, Simone Tilmes, Makato Deushi, Beatrice Josse, David Plummer, and Kengo Sudo
Atmos. Chem. Phys., 18, 11927–11948,Short summary
The co-occurrence of heat waves and pollution events and the resulting high mortality rates emphasize the importance of the co-occurrence of pollution and temperature extremes. We analyze ozone and temperature extremes and their joint occurrence over the United States during the summer months (JJA) in measurement data and in model simulations of the present and future climates.
Cenlin He, Mark G. Flanner, Fei Chen, Michael Barlage, Kuo-Nan Liou, Shichang Kang, Jing Ming, and Yun Qian
Atmos. Chem. Phys., 18, 11507–11527,Short summary
Snow albedo plays a key role in the Earth and climate system. It can be affected by impurities and snow properties. This study implements new parameterizations into a widely used snow model to account for effects of snow shape and black carbon–snow mixing state on snow albedo reduction in the Tibetan Plateau. This study points toward an imperative need for extensive measurements and improved model characterization of snow grain shape and aerosol–snow mixing state in Tibet and elsewhere.
Hua Song, Zhibo Zhang, Po-Lun Ma, Steven Ghan, and Minghuai Wang
Geosci. Model Dev., 11, 3147–3158,
Ciao-Kai Liang, J. Jason West, Raquel A. Silva, Huisheng Bian, Mian Chin, Yanko Davila, Frank J. Dentener, Louisa Emmons, Johannes Flemming, Gerd Folberth, Daven Henze, Ulas Im, Jan Eiof Jonson, Terry J. Keating, Tom Kucsera, Allen Lenzen, Meiyun Lin, Marianne Tronstad Lund, Xiaohua Pan, Rokjin J. Park, R. Bradley Pierce, Takashi Sekiya, Kengo Sudo, and Toshihiko Takemura
Atmos. Chem. Phys., 18, 10497–10520,Short summary
Emissions from one continent affect air quality and health elsewhere. Here we quantify the effects of intercontinental PM2.5 and ozone transport on human health using a new multi-model ensemble, evaluating the health effects of emissions from six world regions and three emission source sectors. Emissions from one region have significant health impacts outside of that source region; similarly, foreign emissions contribute significantly to air-pollution-related deaths in several world regions.
Jordan L. Schnell, Vaishali Naik, Larry W. Horowitz, Fabien Paulot, Jingqiu Mao, Paul Ginoux, Ming Zhao, and Kirpa Ram
Atmos. Chem. Phys., 18, 10157–10175,Short summary
We evaluate the ability of a developmental version of the NOAA GFDL Atmospheric Model, version 4 to simulate observed wintertime pollution and its relationship to weather over Northern India, one of the most densely populated and polluted regions in world. We also compare two emission inventories and find that the newest version dramatically improves our simulation. Observed and modeled pollution is the highest within the Indo-Gangetic Plain, where it is closely related to near-surface weather.
Ragnhild Bieltvedt Skeie, Terje Berntsen, Magne Aldrin, Marit Holden, and Gunnar Myhre
Earth Syst. Dynam., 9, 879–894,Short summary
A key question in climate science is how the global mean surface temperature responds to changes in greenhouse gases. This dependency is quantified by the climate sensitivity, which is determined by the complex feedbacks in the climate system. In this study observations of past climate change are used to estimate this sensitivity. Our estimate is consistent with values for the equilibrium climate sensitivity estimated by complex climate models but sensitive to the use of uncertain input data.
Stefano Galmarini, Ioannis Kioutsioukis, Efisio Solazzo, Ummugulsum Alyuz, Alessandra Balzarini, Roberto Bellasio, Anna M. K. Benedictow, Roberto Bianconi, Johannes Bieser, Joergen Brandt, Jesper H. Christensen, Augustin Colette, Gabriele Curci, Yanko Davila, Xinyi Dong, Johannes Flemming, Xavier Francis, Andrea Fraser, Joshua Fu, Daven K. Henze, Christian Hogrefe, Ulas Im, Marta Garcia Vivanco, Pedro Jiménez-Guerrero, Jan Eiof Jonson, Nutthida Kitwiroon, Astrid Manders, Rohit Mathur, Laura Palacios-Peña, Guido Pirovano, Luca Pozzoli, Marie Prank, Martin Schultz, Rajeet S. Sokhi, Kengo Sudo, Paolo Tuccella, Toshihiko Takemura, Takashi Sekiya, and Alper Unal
Atmos. Chem. Phys., 18, 8727–8744,Short summary
An ensemble of model results relating to ozone concentrations in Europe in 2010 has been produced and studied. The novelty consists in the fact that the ensemble is made of results of models working at two different scales (regional and global), therefore contributing in detail two different parts of the atmospheric spectrum. The ensemble defined as a hybrid has been studied in detail and shown to bring additional value to the assessment of air quality.
Tao Tang, Drew Shindell, Bjørn H. Samset, Oliviér Boucher, Piers M. Forster, Øivind Hodnebrog, Gunnar Myhre, Jana Sillmann, Apostolos Voulgarakis, Timothy Andrews, Gregory Faluvegi, Dagmar Fläschner, Trond Iversen, Matthew Kasoar, Viatcheslav Kharin, Alf Kirkevåg, Jean-Francois Lamarque, Dirk Olivié, Thomas Richardson, Camilla W. Stjern, and Toshihiko Takemura
Atmos. Chem. Phys., 18, 8439–8452,
Sandip S. Dhomse, Douglas Kinnison, Martyn P. Chipperfield, Ross J. Salawitch, Irene Cionni, Michaela I. Hegglin, N. Luke Abraham, Hideharu Akiyoshi, Alex T. Archibald, Ewa M. Bednarz, Slimane Bekki, Peter Braesicke, Neal Butchart, Martin Dameris, Makoto Deushi, Stacey Frith, Steven C. Hardiman, Birgit Hassler, Larry W. Horowitz, Rong-Ming Hu, Patrick Jöckel, Beatrice Josse, Oliver Kirner, Stefanie Kremser, Ulrike Langematz, Jared Lewis, Marion Marchand, Meiyun Lin, Eva Mancini, Virginie Marécal, Martine Michou, Olaf Morgenstern, Fiona M. O'Connor, Luke Oman, Giovanni Pitari, David A. Plummer, John A. Pyle, Laura E. Revell, Eugene Rozanov, Robyn Schofield, Andrea Stenke, Kane Stone, Kengo Sudo, Simone Tilmes, Daniele Visioni, Yousuke Yamashita, and Guang Zeng
Atmos. Chem. Phys., 18, 8409–8438,Short summary
We analyse simulations from the Chemistry-Climate Model Initiative (CCMI) to estimate the return dates of the stratospheric ozone layer from depletion by anthropogenic chlorine and bromine. The simulations from 20 models project that global column ozone will return to 1980 values in 2047 (uncertainty range 2042–2052). Return dates in other regions vary depending on factors related to climate change and importance of chlorine and bromine. Column ozone in the tropics may continue to decline.
Inger Helene Hafsahl Karset, Terje Koren Berntsen, Trude Storelvmo, Kari Alterskjær, Alf Grini, Dirk Olivié, Alf Kirkevåg, Øyvind Seland, Trond Iversen, and Michael Schulz
Atmos. Chem. Phys., 18, 7669–7690,Short summary
This study highlights the role of oxidants in modeling of the preindustrial-to-present-day aerosol indirect effects. We argue that the aerosol precursor gases should be exposed to oxidants of its era to get a more correct representation of secondary aerosol formation. Our global model simulations show that the total aerosol indirect effect changes from −1.32 to −1.07 W m−2 when the precursor gases in the preindustrial simulation are exposed to preindustrial instead of present-day oxidants.
Nan Li, Qingyang He, Jim Greenberg, Alex Guenther, Jingyi Li, Junji Cao, Jun Wang, Hong Liao, Qiyuan Wang, and Qiang Zhang
Atmos. Chem. Phys., 18, 7489–7507,Short summary
O3 pollution has been increasing in most Chinese cities in recent years. Our study reveals that the synergistic impact of individual source contributions to O3 formation should be considered in the formation of air pollution control strategies, especially for big cities in the vicinity of forests.
Xiaokang Wu, Huang Yang, Darryn W. Waugh, Clara Orbe, Simone Tilmes, and Jean-Francois Lamarque
Atmos. Chem. Phys., 18, 7439–7452,Short summary
The seasonal and interannual variability of transport times from northern mid-latitudes into the southern hemisphere is examined using simulations of
agetracers. The largest variability occurs near the surface close to the tropical convergence zones, but the peak is further south and there is a smaller tropical–extratropical contrast for tracers with more rapid loss. Hence the variability of trace gases in the southern extratropics will vary with their chemical lifetime.
Clara Orbe, Huang Yang, Darryn W. Waugh, Guang Zeng, Olaf Morgenstern, Douglas E. Kinnison, Jean-Francois Lamarque, Simone Tilmes, David A. Plummer, John F. Scinocca, Beatrice Josse, Virginie Marecal, Patrick Jöckel, Luke D. Oman, Susan E. Strahan, Makoto Deushi, Taichu Y. Tanaka, Kohei Yoshida, Hideharu Akiyoshi, Yousuke Yamashita, Andreas Stenke, Laura Revell, Timofei Sukhodolov, Eugene Rozanov, Giovanni Pitari, Daniele Visioni, Kane A. Stone, Robyn Schofield, and Antara Banerjee
Atmos. Chem. Phys., 18, 7217–7235,Short summary
In this study we compare a few atmospheric transport properties among several numerical models that are used to study the influence of atmospheric chemistry on climate. We show that there are large differences among models in terms of the timescales that connect the Northern Hemisphere midlatitudes, where greenhouse gases and ozone-depleting substances are emitted, to the Southern Hemisphere. Our results may have important implications for how models represent atmospheric composition.
Jiani Tan, Joshua S. Fu, Frank Dentener, Jian Sun, Louisa Emmons, Simone Tilmes, Kengo Sudo, Johannes Flemming, Jan Eiof Jonson, Sylvie Gravel, Huisheng Bian, Yanko Davila, Daven K. Henze, Marianne T. Lund, Tom Kucsera, Toshihiko Takemura, and Terry Keating
Atmos. Chem. Phys., 18, 6847–6866,Short summary
We study the distributions of sulfur and nitrogen deposition, which are associated with current environmental issues such as formation of acid rain and ecosystem eutrophication and result in widespread problems such as loss of environmental diversity, harming the crop yield and even food insecurity. According to our study, both the amount and distribution of sulfate and nitrogen deposition have changed significantly in the last decade, particularly in East Asia, South Asia and Southeast Asia.
Michael J. Prather, Clare M. Flynn, Xin Zhu, Stephen D. Steenrod, Sarah A. Strode, Arlene M. Fiore, Gustavo Correa, Lee T. Murray, and Jean-Francois Lamarque
Atmos. Meas. Tech., 11, 2653–2668,Short summary
A new protocol for merging in situ atmospheric chemistry measurements with 3-D models is developed. This technique can identify the most reactive air parcels in terms of tropospheric production/loss of O3 & CH4. This approach highlights differences in 6 global chemistry models even with composition specified. Thus in situ measurements from, e.g., NASA's ATom mission can be used to develop a chemical climatology of, not only the key species, but also the rates of key reactions in each air parcel.
Qiyuan Wang, Junji Cao, Yongming Han, Jie Tian, Chongshu Zhu, Yonggang Zhang, Ningning Zhang, Zhenxing Shen, Haiyan Ni, Shuyu Zhao, and Jiarui Wu
Atmos. Chem. Phys., 18, 4639–4656,Short summary
Black carbon (BC) aerosol in the Tibetan Plateau (TP) has important effects on the regional climate and hydrological processes in South and East Asia. We characterized BC at a high-altitude remote site in the southeastern Tibetan Plateau using a single-particle soot photometer and a photoacoustic extinctiometer. Our study provides insight into the sources and evolution of BC aerosol on the TP, and the results will be useful for improving models of the radiative effects in this area.
Takashi Sekiya, Kazuyuki Miyazaki, Koji Ogochi, Kengo Sudo, and Masayuki Takigawa
Geosci. Model Dev., 11, 959–988,Short summary
We evaluate global tropospheric NO2 simulations using a chemical transport model (CTM) at horizontal resolutions of 0.56, 1.1, and 2.8°. Agreement against satellite retrievals improved greatly at 0.56 and 1.1° resolutions (compared to 2.8°) over polluted and biomass burning regions, especially over areas with strong local sources, such as a megacity. The evaluations demonstrate the potential of using a high-resolution global CTM for studying megacity-scale air pollutants across the entire globe.
Katrina M. Macdonald, Sangeeta Sharma, Desiree Toom, Alina Chivulescu, Andrew Platt, Mike Elsasser, Lin Huang, Richard Leaitch, Nathan Chellman, Joseph R. McConnell, Heiko Bozem, Daniel Kunkel, Ying Duan Lei, Cheol-Heon Jeong, Jonathan P. D. Abbatt, and Greg J. Evans
Atmos. Chem. Phys., 18, 3485–3503,Short summary
The sources of key contaminants in Arctic snow may be an important factor in understanding the rapid climate changes observed in the Arctic. Fresh snow samples collected frequently through the winter season were analyzed for major constituents. Temporally refined source apportionment via positive matrix factorization in conjunction with FLEXPART suggested potential source characteristics and locations. The identity of these sources and their relative contribution to key analytes is discussed.
Jian Sun, Zhenxing Shen, Yu Huang, Junji Cao, Steven Sai Hang Ho, Xinyi Niu, Taobo Wang, Qian Zhang, Yali Lei, Hongmei Xu, and Hongxia Liu
Atmos. Chem. Phys. Discuss.,
Revised manuscript not accepted
Jingqiu Mao, Annmarie Carlton, Ronald C. Cohen, William H. Brune, Steven S. Brown, Glenn M. Wolfe, Jose L. Jimenez, Havala O. T. Pye, Nga Lee Ng, Lu Xu, V. Faye McNeill, Kostas Tsigaridis, Brian C. McDonald, Carsten Warneke, Alex Guenther, Matthew J. Alvarado, Joost de Gouw, Loretta J. Mickley, Eric M. Leibensperger, Rohit Mathur, Christopher G. Nolte, Robert W. Portmann, Nadine Unger, Mika Tosca, and Larry W. Horowitz
Atmos. Chem. Phys., 18, 2615–2651,Short summary
This paper is aimed at discussing progress in evaluating, diagnosing, and improving air quality and climate modeling using comparisons to SAS observations as a guide to thinking about improvements to mechanisms and parameterizations in models.
Nancy A. N. Bertler, Howard Conway, Dorthe Dahl-Jensen, Daniel B. Emanuelsson, Mai Winstrup, Paul T. Vallelonga, James E. Lee, Ed J. Brook, Jeffrey P. Severinghaus, Taylor J. Fudge, Elizabeth D. Keller, W. Troy Baisden, Richard C. A. Hindmarsh, Peter D. Neff, Thomas Blunier, Ross Edwards, Paul A. Mayewski, Sepp Kipfstuhl, Christo Buizert, Silvia Canessa, Ruzica Dadic, Helle A. Kjær, Andrei Kurbatov, Dongqi Zhang, Edwin D. Waddington, Giovanni Baccolo, Thomas Beers, Hannah J. Brightley, Lionel Carter, David Clemens-Sewall, Viorela G. Ciobanu, Barbara Delmonte, Lukas Eling, Aja Ellis, Shruthi Ganesh, Nicholas R. Golledge, Skylar Haines, Michael Handley, Robert L. Hawley, Chad M. Hogan, Katelyn M. Johnson, Elena Korotkikh, Daniel P. Lowry, Darcy Mandeno, Robert M. McKay, James A. Menking, Timothy R. Naish, Caroline Noerling, Agathe Ollive, Anaïs Orsi, Bernadette C. Proemse, Alexander R. Pyne, Rebecca L. Pyne, James Renwick, Reed P. Scherer, Stefanie Semper, Marius Simonsen, Sharon B. Sneed, Eric J. Steig, Andrea Tuohy, Abhijith Ulayottil Venugopal, Fernando Valero-Delgado, Janani Venkatesh, Feitang Wang, Shimeng Wang, Dominic A. Winski, V. Holly L. Winton, Arran Whiteford, Cunde Xiao, Jiao Yang, and Xin Zhang
Clim. Past, 14, 193–214,Short summary
Temperature and snow accumulation records from the annually dated Roosevelt Island Climate Evolution (RICE) ice core show that for the past 2 700 years, the eastern Ross Sea warmed, while the western Ross Sea showed no trend and West Antarctica cooled. From the 17th century onwards, this dipole relationship changed. Now all three regions show concurrent warming, with snow accumulation declining in West Antarctica and the eastern Ross Sea.
Jingyi Li, Jingqiu Mao, Arlene M. Fiore, Ronald C. Cohen, John D. Crounse, Alex P. Teng, Paul O. Wennberg, Ben H. Lee, Felipe D. Lopez-Hilfiker, Joel A. Thornton, Jeff Peischl, Ilana B. Pollack, Thomas B. Ryerson, Patrick Veres, James M. Roberts, J. Andrew Neuman, John B. Nowak, Glenn M. Wolfe, Thomas F. Hanisco, Alan Fried, Hanwant B. Singh, Jack Dibb, Fabien Paulot, and Larry W. Horowitz
Atmos. Chem. Phys., 18, 2341–2361,Short summary
We present the first comprehensive model evaluation of summertime reactive oxidized nitrogen using a high-resolution chemistry–climate model with up-to-date isoprene oxidation chemistry, along with a series of observations from aircraft campaigns and ground measurement networks from 2004 to 2013 over the Southeast US. We investigate the impact of NOx emission reductions on changes in reactive nitrogen speciation and export efficiency as well as ozone in the past and future decade.
Lauren Marshall, Anja Schmidt, Matthew Toohey, Ken S. Carslaw, Graham W. Mann, Michael Sigl, Myriam Khodri, Claudia Timmreck, Davide Zanchettin, William T. Ball, Slimane Bekki, James S. A. Brooke, Sandip Dhomse, Colin Johnson, Jean-Francois Lamarque, Allegra N. LeGrande, Michael J. Mills, Ulrike Niemeier, James O. Pope, Virginie Poulain, Alan Robock, Eugene Rozanov, Andrea Stenke, Timofei Sukhodolov, Simone Tilmes, Kostas Tsigaridis, and Fiona Tummon
Atmos. Chem. Phys., 18, 2307–2328,Short summary
We use four global aerosol models to compare the simulated sulfate deposition from the 1815 Mt. Tambora eruption to ice core records. Inter-model volcanic sulfate deposition differs considerably. Volcanic sulfate deposited on polar ice sheets is used to estimate the atmospheric sulfate burden and subsequently radiative forcing of historic eruptions. Our results suggest that deriving such relationships from model simulations may be associated with greater uncertainties than previously thought.
Olaf Morgenstern, Kane A. Stone, Robyn Schofield, Hideharu Akiyoshi, Yousuke Yamashita, Douglas E. Kinnison, Rolando R. Garcia, Kengo Sudo, David A. Plummer, John Scinocca, Luke D. Oman, Michael E. Manyin, Guang Zeng, Eugene Rozanov, Andrea Stenke, Laura E. Revell, Giovanni Pitari, Eva Mancini, Glauco Di Genova, Daniele Visioni, Sandip S. Dhomse, and Martyn P. Chipperfield
Atmos. Chem. Phys., 18, 1091–1114,Short summary
We assess how ozone as simulated by a group of chemistry–climate models responds to variations in man-made climate gases and ozone-depleting substances. We find some agreement, particularly in the middle and upper stratosphere, but also considerable disagreement elsewhere. Such disagreement affects the reliability of future ozone projections based on these models, and also constitutes a source of uncertainty in climate projections using prescribed ozone derived from these simulations.
Theodore K. Koenig, Rainer Volkamer, Sunil Baidar, Barbara Dix, Siyuan Wang, Daniel C. Anderson, Ross J. Salawitch, Pamela A. Wales, Carlos A. Cuevas, Rafael P. Fernandez, Alfonso Saiz-Lopez, Mathew J. Evans, Tomás Sherwen, Daniel J. Jacob, Johan Schmidt, Douglas Kinnison, Jean-François Lamarque, Eric C. Apel, James C. Bresch, Teresa Campos, Frank M. Flocke, Samuel R. Hall, Shawn B. Honomichl, Rebecca Hornbrook, Jørgen B. Jensen, Richard Lueb, Denise D. Montzka, Laura L. Pan, J. Michael Reeves, Sue M. Schauffler, Kirk Ullmann, Andrew J. Weinheimer, Elliot L. Atlas, Valeria Donets, Maria A. Navarro, Daniel Riemer, Nicola J. Blake, Dexian Chen, L. Gregory Huey, David J. Tanner, Thomas F. Hanisco, and Glenn M. Wolfe
Atmos. Chem. Phys., 17, 15245–15270,Short summary
Tropospheric inorganic bromine (BrO and Bry) shows a C-shaped profile over the tropical western Pacific Ocean, and supports previous speculation that marine convection is a source for inorganic bromine from sea salt to the upper troposphere. The Bry profile in the tropical tropopause layer (TTL) is complex, suggesting that the total Bry budget in the TTL is not closed without considering aerosol bromide. The implications for atmospheric composition and bromine sources are discussed.
Sunil Vadakkepuliyambatta, Ragnhild B. Skeie, Gunnar Myhre, Stig B. Dalsøren, Anna Silyakova, Norbert Schmidbauer, Cathrine Lund Myhre, and Jürgen Mienert
Earth Syst. Dynam. Discuss.,
Preprint retractedShort summary
Release of methane, one of the major greenhouse gases, from melting hydrates has been proposed as a mechanism that accelerated global warming in the past. We focus on Arctic Ocean warming as a robust case study for accelerated melting of hydrates, assessing the impact of Arctic methane release on global air temperatures during the next century. Contrary to popular belief, it is shown that methane emissions from melting hydrates from the Arctic seafloor is not a major driver of global warming.
Ruth M. Doherty, Clara Orbe, Guang Zeng, David A. Plummer, Michael J. Prather, Oliver Wild, Meiyun Lin, Drew T. Shindell, and Ian A. Mackenzie
Atmos. Chem. Phys., 17, 14219–14237,Short summary
We investigate how climate change impacts global air pollution transport. To study transport changes, we use a carbon monoxide (CO) tracer species emitted from global sources. We find robust and consistent changes in CO-tracer distributions in climate change simulations performed by four chemistry–climate models in different seasons. We highlight the importance of the co-location of emission source regions and controlling transport processes in determining future pollution transport.
Joseph M. Cook, Andrew J. Hodson, Alex S. Gardner, Mark Flanner, Andrew J. Tedstone, Christopher Williamson, Tristram D. L. Irvine-Fynn, Johan Nilsson, Robert Bryant, and Martyn Tranter
The Cryosphere, 11, 2611–2632,Short summary
Biological growth darkens snow and ice, causing it to melt faster. This is often referred to as
bioalbedo. Quantifying bioalbedo has not been achieved because of difficulties in isolating the biological contribution from the optical properties of ice and snow, and from inorganic impurities in field studies. In this paper, we provide a physical model that enables bioalbedo to be quantified from first principles and we use it to guide future field studies.
Huisheng Bian, Mian Chin, Didier A. Hauglustaine, Michael Schulz, Gunnar Myhre, Susanne E. Bauer, Marianne T. Lund, Vlassis A. Karydis, Tom L. Kucsera, Xiaohua Pan, Andrea Pozzer, Ragnhild B. Skeie, Stephen D. Steenrod, Kengo Sudo, Kostas Tsigaridis, Alexandra P. Tsimpidi, and Svetlana G. Tsyro
Atmos. Chem. Phys., 17, 12911–12940,Short summary
Atmospheric nitrate contributes notably to total aerosol mass in the present day and is likely to be more important over the next century, with a projected decline in SO2 and NOx emissions and increase in NH3 emissions. This paper investigates atmospheric nitrate using multiple global models and measurements. The study is part of the AeroCom phase III activity. The study is the first attempt to look at global atmospheric nitrate simulation at physical and chemical process levels.
Maria Sand, Bjørn H. Samset, Yves Balkanski, Susanne Bauer, Nicolas Bellouin, Terje K. Berntsen, Huisheng Bian, Mian Chin, Thomas Diehl, Richard Easter, Steven J. Ghan, Trond Iversen, Alf Kirkevåg, Jean-François Lamarque, Guangxing Lin, Xiaohong Liu, Gan Luo, Gunnar Myhre, Twan van Noije, Joyce E. Penner, Michael Schulz, Øyvind Seland, Ragnhild B. Skeie, Philip Stier, Toshihiko Takemura, Kostas Tsigaridis, Fangqun Yu, Kai Zhang, and Hua Zhang
Atmos. Chem. Phys., 17, 12197–12218,Short summary
The role of aerosols in the changing polar climate is not well understood and the aerosols are poorly constrained in the models. In this study we have compared output from 16 different aerosol models with available observations at both poles. We show that the model median is representative of the observations, but the model spread is large. The Arctic direct aerosol radiative effect over the industrial area is positive during spring due to black carbon and negative during summer due to sulfate.
Marielle Saunois, Philippe Bousquet, Ben Poulter, Anna Peregon, Philippe Ciais, Josep G. Canadell, Edward J. Dlugokencky, Giuseppe Etiope, David Bastviken, Sander Houweling, Greet Janssens-Maenhout, Francesco N. Tubiello, Simona Castaldi, Robert B. Jackson, Mihai Alexe, Vivek K. Arora, David J. Beerling, Peter Bergamaschi, Donald R. Blake, Gordon Brailsford, Lori Bruhwiler, Cyril Crevoisier, Patrick Crill, Kristofer Covey, Christian Frankenberg, Nicola Gedney, Lena Höglund-Isaksson, Misa Ishizawa, Akihiko Ito, Fortunat Joos, Heon-Sook Kim, Thomas Kleinen, Paul Krummel, Jean-François Lamarque, Ray Langenfelds, Robin Locatelli, Toshinobu Machida, Shamil Maksyutov, Joe R. Melton, Isamu Morino, Vaishali Naik, Simon O'Doherty, Frans-Jan W. Parmentier, Prabir K. Patra, Changhui Peng, Shushi Peng, Glen P. Peters, Isabelle Pison, Ronald Prinn, Michel Ramonet, William J. Riley, Makoto Saito, Monia Santini, Ronny Schroeder, Isobel J. Simpson, Renato Spahni, Atsushi Takizawa, Brett F. Thornton, Hanqin Tian, Yasunori Tohjima, Nicolas Viovy, Apostolos Voulgarakis, Ray Weiss, David J. Wilton, Andy Wiltshire, Doug Worthy, Debra Wunch, Xiyan Xu, Yukio Yoshida, Bowen Zhang, Zhen Zhang, and Qiuan Zhu
Atmos. Chem. Phys., 17, 11135–11161,Short summary
Following the Global Methane Budget 2000–2012 published in Saunois et al. (2016), we use the same dataset of bottom-up and top-down approaches to discuss the variations in methane emissions over the period 2000–2012. The changes in emissions are discussed both in terms of trends and quasi-decadal changes. The ensemble gathered here allows us to synthesise the robust changes in terms of regional and sectorial contributions to the increasing methane emissions.
Benjamin M. Sanderson, Yangyang Xu, Claudia Tebaldi, Michael Wehner, Brian O'Neill, Alexandra Jahn, Angeline G. Pendergrass, Flavio Lehner, Warren G. Strand, Lei Lin, Reto Knutti, and Jean Francois Lamarque
Earth Syst. Dynam., 8, 827–847,Short summary
We present the results of a set of climate simulations designed to simulate futures in which the Earth's temperature is stabilized at the levels referred to in the 2015 Paris Agreement. We consider the necessary future emissions reductions and the aspects of extreme weather which differ significantly between the 2 and 1.5 °C climate in the simulations.
Borgar Aamaas, Terje K. Berntsen, Jan S. Fuglestvedt, Keith P. Shine, and William J. Collins
Atmos. Chem. Phys., 17, 10795–10809,Short summary
The climate impacts for emissions of different pollutants can be made comparable with weighting factors. This article estimates these weights based on temperature change for short-lived pollutants, such as methane and black carbon. Emissions from different seasons and regions are compared, for instance Europe and East Asia. The responses are calculated for four regions, where we see that the responses can be much higher in the Arctic than globally in some cases.
Maria A. Navarro, Alfonso Saiz-Lopez, Carlos A. Cuevas, Rafael P. Fernandez, Elliot Atlas, Xavier Rodriguez-Lloveras, Douglas Kinnison, Jean-Francois Lamarque, Simone Tilmes, Troy Thornberry, Andrew Rollins, James W. Elkins, Eric J. Hintsa, and Fred L. Moore
Atmos. Chem. Phys., 17, 9917–9930,Short summary
Inorganic bromine (Bry) plays an important role in ozone layer depletion. Based on aircraft observations of organic bromine species and chemistry simulations, we model the Bry abundances over the Pacific tropical tropopause. Our results show BrO and Br as the dominant species during daytime hours, and BrCl and BrONO2 as the nighttime dominant species over the western and eastern Pacific, respectively. The difference in the partitioning is due to changes in the abundance of O3, NO2, and Cly.
Jun Tao, Leiming Zhang, Junji Cao, and Renjian Zhang
Atmos. Chem. Phys., 17, 9485–9518,Short summary
In this study, studies on PM2.5 chemical composition, source apportionment and its impact on aerosol optical properties across China are thoroughly reviewed, and historical emission control policies in China and their effectiveness in reducing PM2.5 are discussed.
Rachael H. Rhodes, Xin Yang, Eric W. Wolff, Joseph R. McConnell, and Markus M. Frey
Atmos. Chem. Phys., 17, 9417–9433,Short summary
Sea salt aerosol comes from the open ocean or the sea ice surface. In the polar regions, this opens up the possibility of reconstructing sea ice history using sea salt recorded in ice cores. We use a chemical transport model to demonstrate that the sea ice source of aerosol is important in the Arctic. For the first time, we simulate realistic Greenland ice core sea salt in a process-based model. The importance of the sea ice source increases from south to north across the Greenland ice sheet.
Wolfgang Knorr, Frank Dentener, Jean-François Lamarque, Leiwen Jiang, and Almut Arneth
Atmos. Chem. Phys., 17, 9223–9236,Short summary
Wildfires cause considerable air pollution, and climate change is usually expected to increase both wildfire activity and air pollution from those fires. This study takes a closer look at the problem by examining the role of demographic changes in addition to climate change. It finds that demographics will be the main driver of changes in wildfire activity in many parts of the developing world. Air pollution from wildfires will remain significant, with major implications for air quality policy.
Michael J. Prather, Xin Zhu, Clare M. Flynn, Sarah A. Strode, Jose M. Rodriguez, Stephen D. Steenrod, Junhua Liu, Jean-Francois Lamarque, Arlene M. Fiore, Larry W. Horowitz, Jingqiu Mao, Lee T. Murray, Drew T. Shindell, and Steven C. Wofsy
Atmos. Chem. Phys., 17, 9081–9102,Short summary
We present a new approach for comparing atmospheric chemistry models with measurements based on what these models are used to do, i.e., calculate changes in ozone and methane, prime greenhouse gases. This method anticipates a new type of measurements from the NASA Atmospheric Tomography (ATom) mission. In comparing the mixture of species within air parcels, we focus on those responsible for key chemical changes and weight these parcels by their chemical reactivity.
Chris Huntingford, Hui Yang, Anna Harper, Peter M. Cox, Nicola Gedney, Eleanor J. Burke, Jason A. Lowe, Garry Hayman, William J. Collins, Stephen M. Smith, and Edward Comyn-Platt
Earth Syst. Dynam., 8, 617–626,Short summary
Recent UNFCCC climate meetings have placed much emphasis on constraining global warming to remain below 2 °C. The 2015 Paris meeting went further and gave an aspiration to fulfil a 1.5 °C threshold. We provide a flexible set of algebraic global temperature profiles that stabilise to either target. This will potentially allow the climate research community to estimate local climatic implications for these temperature profiles, along with emissions trajectories to fulfil them.
Hyun-Deok Choi, Hongyu Liu, James H. Crawford, David B. Considine, Dale J. Allen, Bryan N. Duncan, Larry W. Horowitz, Jose M. Rodriguez, Susan E. Strahan, Lin Zhang, Xiong Liu, Megan R. Damon, and Stephen D. Steenrod
Atmos. Chem. Phys., 17, 8429–8452,Short summary
We evaluate global ozone–carbon monoxide (O3–CO) correlations in a chemistry and transport model during July–August with TES-Aura satellite observations and examine the sensitivity of model simulations to input meteorological data and emissions. Results show that O3–CO correlations may be used effectively to constrain the sources of regional tropospheric O3 in global 3-D models, especially for those regions where convective transport of pollution plays an important role.
Marianne T. Lund, Borgar Aamaas, Terje Berntsen, Lisa Bock, Ulrike Burkhardt, Jan S. Fuglestvedt, and Keith P. Shine
Earth Syst. Dynam., 8, 547–563,
Tatsuya Nagashima, Kengo Sudo, Hajime Akimoto, Junichi Kurokawa, and Toshimasa Ohara
Atmos. Chem. Phys., 17, 8231–8246,Short summary
We showed the large contribution of different source regions in Asia to the recent increasing trend in surface ozone over Japan by using a global chemical transport model. China accounted for the largest part of the increasing trend, not only through the domestic ozone production (36 %) but also the ozone production in the adjacent countries due to the ozone precursors emitted in China (10 %). Other factors such as temporal change in climate and methane concentration were also investigated.
Alex R. Baker, Maria Kanakidou, Katye E. Altieri, Nikos Daskalakis, Gregory S. Okin, Stelios Myriokefalitakis, Frank Dentener, Mitsuo Uematsu, Manmohan M. Sarin, Robert A. Duce, James N. Galloway, William C. Keene, Arvind Singh, Lauren Zamora, Jean-Francois Lamarque, Shih-Chieh Hsu, Shital S. Rohekar, and Joseph M. Prospero
Atmos. Chem. Phys., 17, 8189–8210,Short summary
Man's activities have greatly increased the amount of nitrogen emitted into the atmosphere. Some of this nitrogen is transported to the world's oceans, where it may affect microscopic marine plants and cause ecological problems. The huge size of the oceans makes direct monitoring of nitrogen inputs impossible, so computer models must be used to assess this issue. We find that current models reproduce observed nitrogen deposition to the oceans reasonably well and recommend future improvements.
Eri Saikawa, Hankyul Kim, Min Zhong, Alexander Avramov, Yu Zhao, Greet Janssens-Maenhout, Jun-ichi Kurokawa, Zbigniew Klimont, Fabian Wagner, Vaishali Naik, Larry W. Horowitz, and Qiang Zhang
Atmos. Chem. Phys., 17, 6393–6421,Short summary
We analyze differences in existing air pollutant emission estimates to better understand the magnitude of emissions as well as the source regions and sectors of air pollution in China. We find large disagreements among the inventories, and we show that these differences have a significant impact on regional air quality simulations. Better understanding of air pollutant emissions at more disaggregated levels is essential for air pollution mitigation in China.
Juliana D'Andrilli, Christine M. Foreman, Michael Sigl, John C. Priscu, and Joseph R. McConnell
Clim. Past, 13, 533–544,Short summary
Climate-driven trends in fluorescent organic matter (OM) markers from Antarctic ice cores revealed fluctuations over 21.0 kyr, reflecting environmental shifts as a result of global ecosystem response in a warming climate. Precursors of lignin-like fluorescent chemical species were detected as OM markers from the Last Glacial Maximum to the mid-Holocene. Holocene ice contained the most complex lignin-like fluorescent OM markers. Thus, ice cores contain paleoecological OM markers of Earth’s past.
Marianne T. Lund, Terje K. Berntsen, and Bjørn H. Samset
Atmos. Chem. Phys., 17, 6003–6022,Short summary
This study investigates possibilities for improving the representation of black carbon (BC) distribution in a global atmospheric chemistry-transport model by exploring uncertainties in key processes controlling the removal of aerosols from the atmosphere. Our results provide an increased understanding of the processes contributing to uncertainties in the BC abundance and climate impact and underline the importance of more observations and experimental data further constrain models.
Katrina M. Macdonald, Sangeeta Sharma, Desiree Toom, Alina Chivulescu, Sarah Hanna, Allan K. Bertram, Andrew Platt, Mike Elsasser, Lin Huang, David Tarasick, Nathan Chellman, Joseph R. McConnell, Heiko Bozem, Daniel Kunkel, Ying Duan Lei, Greg J. Evans, and Jonathan P. D. Abbatt
Atmos. Chem. Phys., 17, 5775–5788,Short summary
Rapid climate changes within the Arctic have highlighted existing uncertainties in the transport of contaminants to Arctic snow. Fresh snow samples collected frequently through the winter season were analyzed for major constituents creating a unique record of Arctic snow. Comparison with simultaneous atmospheric measurements provides insight into the driving processes in the transfer of contaminants from air to snow. The relative importance of deposition mechanisms over the season is proposed.
Min Huang, Gregory R. Carmichael, R. Bradley Pierce, Duseong S. Jo, Rokjin J. Park, Johannes Flemming, Louisa K. Emmons, Kevin W. Bowman, Daven K. Henze, Yanko Davila, Kengo Sudo, Jan Eiof Jonson, Marianne Tronstad Lund, Greet Janssens-Maenhout, Frank J. Dentener, Terry J. Keating, Hilke Oetjen, and Vivienne H. Payne
Atmos. Chem. Phys., 17, 5721–5750,Short summary
In support of the HTAP phase 2 experiment, we conducted a number of regional-scale Sulfur Transport and dEposition Model base and sensitivity simulations over North America during May–June 2010. The STEM chemical boundary conditions were downscaled from three (GEOS-Chem, RAQMS, and ECMWF C-IFS) global chemical transport models' simulations. Analyses were performed on large spatial–temporal scales relative to HTAP1 and also on subcontinental and event scales including the use of satellite data.
Mackenzie M. Grieman, Murat Aydin, Diedrich Fritzsche, Joseph R. McConnell, Thomas Opel, Michael Sigl, and Eric S. Saltzman
Clim. Past, 13, 395–410,Short summary
Wildfires impact ecosystems, climate, and atmospheric chemistry. Records that predate instrumental records and industrialization are needed to study the climatic controls on biomass burning. In this study, we analyzed organic chemicals produced from burning of plant matter that were preserved in an ice core from the Eurasian Arctic. These chemicals are elevated during three periods that have similar timing to climate variability. This is the first millennial-scale record of these chemicals.
Thomas Gasser, Glen P. Peters, Jan S. Fuglestvedt, William J. Collins, Drew T. Shindell, and Philippe Ciais
Earth Syst. Dynam., 8, 235–253,Short summary
Emission metrics such as GWP or GTP are used to put non-CO2 species on a
CO2-equivalentscale. In the fifth IPCC report the metrics are inconsistent, as the climate–carbon feedback is included only for CO2 but not for non-CO2 species. Here, we simulate a new impulse response function for the feedback, and we use it to correct the metrics. For instance, 1 g of CH4 is equivalent to 31 g of CO2 (instead of 28 g) following the corrected GWP100 metric. It is 34 g if other factors are also updated.
Borgar Aamaas, Terje K. Berntsen, Jan S. Fuglestvedt, and Glen P. Peters
Earth Syst. Dynam. Discuss.,
Manuscript not accepted for further review
Meiyun Lin, Larry W. Horowitz, Richard Payton, Arlene M. Fiore, and Gail Tonnesen
Atmos. Chem. Phys., 17, 2943–2970,Short summary
US ozone pollution responds to varying global-to-regional precursor emissions and climate, with implications for designing effective air quality control policies. Asian anthropogenic emissions of ozone precursors tripled since 1990, contributing 65 % to western US ozone increases in spring, outpacing ozone decreases attained via 50 % US emission controls. In the eastern US, if emissions had not declined, more frequent hot extremes since 1990 would have worsened the highest ozone events in summer.
Gunnar Myhre, Wenche Aas, Ribu Cherian, William Collins, Greg Faluvegi, Mark Flanner, Piers Forster, Øivind Hodnebrog, Zbigniew Klimont, Marianne T. Lund, Johannes Mülmenstädt, Cathrine Lund Myhre, Dirk Olivié, Michael Prather, Johannes Quaas, Bjørn H. Samset, Jordan L. Schnell, Michael Schulz, Drew Shindell, Ragnhild B. Skeie, Toshihiko Takemura, and Svetlana Tsyro
Atmos. Chem. Phys., 17, 2709–2720,Short summary
Over the past decades, the geographical distribution of emissions of substances that alter the atmospheric energy balance has changed due to economic growth and pollution regulations. Here, we show the resulting changes to aerosol and ozone abundances and their radiative forcing using recently updated emission data for the period 1990–2015, as simulated by seven global atmospheric composition models. The global mean radiative forcing is more strongly positive than reported in IPCC AR5.
Olaf Morgenstern, Michaela I. Hegglin, Eugene Rozanov, Fiona M. O'Connor, N. Luke Abraham, Hideharu Akiyoshi, Alexander T. Archibald, Slimane Bekki, Neal Butchart, Martyn P. Chipperfield, Makoto Deushi, Sandip S. Dhomse, Rolando R. Garcia, Steven C. Hardiman, Larry W. Horowitz, Patrick Jöckel, Beatrice Josse, Douglas Kinnison, Meiyun Lin, Eva Mancini, Michael E. Manyin, Marion Marchand, Virginie Marécal, Martine Michou, Luke D. Oman, Giovanni Pitari, David A. Plummer, Laura E. Revell, David Saint-Martin, Robyn Schofield, Andrea Stenke, Kane Stone, Kengo Sudo, Taichu Y. Tanaka, Simone Tilmes, Yousuke Yamashita, Kohei Yoshida, and Guang Zeng
Geosci. Model Dev., 10, 639–671,Short summary
We present a review of the make-up of 20 models participating in the Chemistry–Climate Model Initiative (CCMI). In comparison to earlier such activities, most of these models comprise a whole-atmosphere chemistry, and several of them include an interactive ocean module. This makes them suitable for studying the interactions of tropospheric air quality, stratospheric ozone, and climate. The paper lays the foundation for other studies using the CCMI simulations for scientific analysis.
William J. Collins, Jean-François Lamarque, Michael Schulz, Olivier Boucher, Veronika Eyring, Michaela I. Hegglin, Amanda Maycock, Gunnar Myhre, Michael Prather, Drew Shindell, and Steven J. Smith
Geosci. Model Dev., 10, 585–607,Short summary
We have designed a set of climate model experiments called the Aerosol Chemistry Model Intercomparison Project (AerChemMIP). These are designed to quantify the climate and air quality impacts of aerosols and chemically reactive gases in the climate models that are used to simulate past and future climate. We hope that many climate modelling centres will choose to run these experiments to help understand the contribution of aerosols and chemistry to climate change.
Rafael P. Fernandez, Douglas E. Kinnison, Jean-Francois Lamarque, Simone Tilmes, and Alfonso Saiz-Lopez
Atmos. Chem. Phys., 17, 1673–1688,Short summary
The inclusion of biogenic very-short lived bromine (VSLBr) in a chemistry-climate model produces an expansion of the ozone hole area of ~ 5 million km2, which is equivalent in magnitude to the recently estimated Antarctic ozone healing due to the reduction of anthropogenic CFCs and halons. The maximum Antarctic ozone hole depletion increases by up to 14 % when natural VSLBr are considered, but does not introduce a significant delay of the modelled ozone return date to 1980 October levels.
Kazuyuki Miyazaki, Henk Eskes, Kengo Sudo, K. Folkert Boersma, Kevin Bowman, and Yugo Kanaya
Atmos. Chem. Phys., 17, 807–837,Short summary
Global surface emissions of nitrogen oxides (NOx) over a 10-year period (2005–2014) are estimated from assimilation of multiple satellite datasets. We present detailed distributions of the estimated NOx emission distributions for all major regions, the diurnal, seasonal, and decadal variability. The estimated emissions show a positive trend over India, China, and the Middle East, and a negative trend over the United States, southern Africa, and western Europe.
Christopher P. Webber, Helen F. Dacre, William J. Collins, and Giacomo Masato
Atmos. Chem. Phys., 17, 867–881,Short summary
The influence of synoptic meteorology on UK PM10 concentration ([PM110]) is analysed. ERA-Interim reanalysis data are used to detect upper-tropospheric wave breaking that explains much of the UK winter synoptic meteorological variability. Wave breaking is shown to positively impact UK [PM10], with a persistent Ω block feature resulting in the greatest probability of exceeding a hazardous UK [PM10]. The meteorological dynamics of UK PM10 exceedances are better understood following this study.
Olivia J. Maselli, Nathan J. Chellman, Mackenzie Grieman, Lawrence Layman, Joseph R. McConnell, Daniel Pasteris, Rachael H. Rhodes, Eric Saltzman, and Michael Sigl
Clim. Past, 13, 39–59,Short summary
We analysed two Greenland ice cores for methanesulfonate (MSA) and bromine (Br) and concluded that both species are suitable proxies for local sea ice conditions. Interpretation of the records reveals that there have been sharp declines in sea ice in these areas in the past 250 years. However, at both sites the Br record deviates from MSA during the industrial period, raising questions about the value of Br as a sea ice proxy during recent periods of high, industrial, atmospheric acid pollution.
Alfonso Saiz-Lopez, John M. C. Plane, Carlos A. Cuevas, Anoop S. Mahajan, Jean-François Lamarque, and Douglas E. Kinnison
Atmos. Chem. Phys., 16, 15593–15604,Short summary
Electronic structure calculations are used to survey possible reactions that HOI and I2 could undergo at night in the lower troposphere, and hence reconcile measurements and models. The reactions NO3 + HOI and I2 + NO3 are included in two models to explore a new nocturnal iodine radical activation mechanism, leading to a reduction of nighttime HOI and I2. This chemistry can have a large impact on NO3 levels in the MBL, and hence upon the nocturnal oxidizing capacity of the marine atmosphere.
Takuro Michibata, Kentaroh Suzuki, Yousuke Sato, and Toshihiko Takemura
Atmos. Chem. Phys., 16, 15413–15424,Short summary
This study identifies a fundamental flaw of a GCM in aerosol–cloud–precipitation interactions. The model predicts a monotonic increase in the LWP in response to increased aerosols, which is in stark contrast to satellite retrievals that show a regional variation in the sign of the LWP response. The model also fails to represent the observed dependency of the LWP response on macrophysical regimes. The model biases are attributed to the autoconversion process, with a lack of buffering mechanisms.
Marielle Saunois, Philippe Bousquet, Ben Poulter, Anna Peregon, Philippe Ciais, Josep G. Canadell, Edward J. Dlugokencky, Giuseppe Etiope, David Bastviken, Sander Houweling, Greet Janssens-Maenhout, Francesco N. Tubiello, Simona Castaldi, Robert B. Jackson, Mihai Alexe, Vivek K. Arora, David J. Beerling, Peter Bergamaschi, Donald R. Blake, Gordon Brailsford, Victor Brovkin, Lori Bruhwiler, Cyril Crevoisier, Patrick Crill, Kristofer Covey, Charles Curry, Christian Frankenberg, Nicola Gedney, Lena Höglund-Isaksson, Misa Ishizawa, Akihiko Ito, Fortunat Joos, Heon-Sook Kim, Thomas Kleinen, Paul Krummel, Jean-François Lamarque, Ray Langenfelds, Robin Locatelli, Toshinobu Machida, Shamil Maksyutov, Kyle C. McDonald, Julia Marshall, Joe R. Melton, Isamu Morino, Vaishali Naik, Simon O'Doherty, Frans-Jan W. Parmentier, Prabir K. Patra, Changhui Peng, Shushi Peng, Glen P. Peters, Isabelle Pison, Catherine Prigent, Ronald Prinn, Michel Ramonet, William J. Riley, Makoto Saito, Monia Santini, Ronny Schroeder, Isobel J. Simpson, Renato Spahni, Paul Steele, Atsushi Takizawa, Brett F. Thornton, Hanqin Tian, Yasunori Tohjima, Nicolas Viovy, Apostolos Voulgarakis, Michiel van Weele, Guido R. van der Werf, Ray Weiss, Christine Wiedinmyer, David J. Wilton, Andy Wiltshire, Doug Worthy, Debra Wunch, Xiyan Xu, Yukio Yoshida, Bowen Zhang, Zhen Zhang, and Qiuan Zhu
Earth Syst. Sci. Data, 8, 697–751,Short summary
An accurate assessment of the methane budget is important to understand the atmospheric methane concentrations and trends and to provide realistic pathways for climate change mitigation. The various and diffuse sources of methane as well and its oxidation by a very short lifetime radical challenge this assessment. We quantify the methane sources and sinks as well as their uncertainties based on both bottom-up and top-down approaches provided by a broad international scientific community.
Nicolas Bellouin, Laura Baker, Øivind Hodnebrog, Dirk Olivié, Ribu Cherian, Claire Macintosh, Bjørn Samset, Anna Esteve, Borgar Aamaas, Johannes Quaas, and Gunnar Myhre
Atmos. Chem. Phys., 16, 13885–13910,Short summary
This study uses global climate models to quantify how strongly man-made emissions of selected pollutants modify the energy budget of the Earth. The pollutants studied interact directly and indirectly with sunlight and terrestrial radiation and remain a relatively short time in the atmosphere, leading to regional and seasonal variations in their impacts. This new data set is useful to compare the potential climate impacts of different pollutants in support of policies to reduce climate change.
Camilla Weum Stjern, Bjørn Hallvard Samset, Gunnar Myhre, Huisheng Bian, Mian Chin, Yanko Davila, Frank Dentener, Louisa Emmons, Johannes Flemming, Amund Søvde Haslerud, Daven Henze, Jan Eiof Jonson, Tom Kucsera, Marianne Tronstad Lund, Michael Schulz, Kengo Sudo, Toshihiko Takemura, and Simone Tilmes
Atmos. Chem. Phys., 16, 13579–13599,Short summary
Air pollution can reach distant regions through intercontinental transport. Here we first present results from the Hemispheric Transport of Air Pollution Phase 2 exercise, where many models performed the same set of coordinated emission-reduction experiments. We find that mitigations have considerable extra-regional effects, and show that this is particularly true for black carbon emissions, as long-range transport elevates aerosols to higher levels where their radiative influence is stronger.
Michel Legrand, Joseph McConnell, Hubertus Fischer, Eric W. Wolff, Susanne Preunkert, Monica Arienzo, Nathan Chellman, Daiana Leuenberger, Olivia Maselli, Philip Place, Michael Sigl, Simon Schüpbach, and Mike Flannigan
Clim. Past, 12, 2033–2059,Short summary
Here, we review previous attempts made to reconstruct past forest fire using chemical signals recorded in Greenland ice. We showed that the Greenland ice records of ammonium, found to be a good fire proxy, consistently indicate changing fire activity in Canada in response to past climatic conditions that occurred since the last 15 000 years, including the Little Ice Age and the last large climatic transition.
V. Holly L. Winton, Ross Edwards, Andrew R. Bowie, Melita Keywood, Alistair G. Williams, Scott D. Chambers, Paul W. Selleck, Maximilien Desservettaz, Marc D. Mallet, and Clare Paton-Walsh
Atmos. Chem. Phys., 16, 12829–12848,Short summary
The deposition of soluble aerosol iron (Fe) can initiate nitrogen fixation and trigger toxic algal blooms in nitrate-poor tropical waters. We present dry season soluble Fe data from northern Australia that reflect coincident dust and biomass burning sources of soluble Fe. Our results show that while biomass burning species are not a direct source of soluble Fe, biomass burning may substantially enhance the solubility of mineral dust with fractional Fe solubility up to 12 % in mixed aerosols.
Brian C. O'Neill, Claudia Tebaldi, Detlef P. van Vuuren, Veronika Eyring, Pierre Friedlingstein, George Hurtt, Reto Knutti, Elmar Kriegler, Jean-Francois Lamarque, Jason Lowe, Gerald A. Meehl, Richard Moss, Keywan Riahi, and Benjamin M. Sanderson
Geosci. Model Dev., 9, 3461–3482,Short summary
The Scenario Model Intercomparison Project (ScenarioMIP) will provide multi-model climate projections based on alternative scenarios of future emissions and land use changes produced with integrated assessment models. The design consists of eight alternative 21st century scenarios plus one large initial condition ensemble and a set of long-term extensions. Climate model projections will facilitate integrated studies of climate change as well as address targeted scientific questions.
B. Quennehen, J.-C. Raut, K. S. Law, N. Daskalakis, G. Ancellet, C. Clerbaux, S.-W. Kim, M. T. Lund, G. Myhre, D. J. L. Olivié, S. Safieddine, R. B. Skeie, J. L. Thomas, S. Tsyro, A. Bazureau, N. Bellouin, M. Hu, M. Kanakidou, Z. Klimont, K. Kupiainen, S. Myriokefalitakis, J. Quaas, S. T. Rumbold, M. Schulz, R. Cherian, A. Shimizu, J. Wang, S.-C. Yoon, and T. Zhu
Atmos. Chem. Phys., 16, 10765–10792,Short summary
This paper evaluates the ability of six global models and one regional model in reproducing short-lived pollutants (defined here as ozone and its precursors, aerosols and black carbon) concentrations over Asia using satellite, ground-based and airborne observations. Key findings are that models homogeneously reproduce the trace gas observations although nitrous oxides are underestimated, whereas the aerosol distributions are heterogeneously reproduced, implicating important uncertainties.
Alemu Gonsamo, Jing M. Chen, Drew T. Shindell, and Gregory P. Asner
Earth Syst. Dynam., 7, 717–734,Short summary
Using 3 decades of observational satellite and field data, we find that long-term changes in sea ice and sea level, plant phenology, and surface temperature are coherent with increases in atmospheric CO2 concentration and other global greenhouse gases. During the same period, natural causes of climate change should only have a net cooling long-term effect, suggesting the observed coherent pattern of changes across Earth's biological and physical systems could only be due to human activities.
Bart van den Hurk, Hyungjun Kim, Gerhard Krinner, Sonia I. Seneviratne, Chris Derksen, Taikan Oki, Hervé Douville, Jeanne Colin, Agnès Ducharne, Frederique Cheruy, Nicholas Viovy, Michael J. Puma, Yoshihide Wada, Weiping Li, Binghao Jia, Andrea Alessandri, Dave M. Lawrence, Graham P. Weedon, Richard Ellis, Stefan Hagemann, Jiafu Mao, Mark G. Flanner, Matteo Zampieri, Stefano Materia, Rachel M. Law, and Justin Sheffield
Geosci. Model Dev., 9, 2809–2832,Short summary
This manuscript describes the setup of the CMIP6 project Land Surface, Snow and Soil Moisture Model Intercomparison Project (LS3MIP).
Lora S. Koenig, Alvaro Ivanoff, Patrick M. Alexander, Joseph A. MacGregor, Xavier Fettweis, Ben Panzer, John D. Paden, Richard R. Forster, Indrani Das, Joesph R. McConnell, Marco Tedesco, Carl Leuschen, and Prasad Gogineni
The Cryosphere, 10, 1739–1752,Short summary
Contemporary climate warming over the Arctic is accelerating mass loss from the Greenland Ice Sheet through increasing surface melt, emphasizing the need to closely monitor surface mass balance in order to improve sea-level rise predictions. Here, we quantify the net annual accumulation over the Greenland Ice Sheet, which comprises the largest component of surface mass balance, at a higher spatial resolution than currently available using high-resolution, airborne-radar data.
Raquel A. Silva, J. Jason West, Jean-François Lamarque, Drew T. Shindell, William J. Collins, Stig Dalsoren, Greg Faluvegi, Gerd Folberth, Larry W. Horowitz, Tatsuya Nagashima, Vaishali Naik, Steven T. Rumbold, Kengo Sudo, Toshihiko Takemura, Daniel Bergmann, Philip Cameron-Smith, Irene Cionni, Ruth M. Doherty, Veronika Eyring, Beatrice Josse, Ian A. MacKenzie, David Plummer, Mattia Righi, David S. Stevenson, Sarah Strode, Sophie Szopa, and Guang Zengast
Atmos. Chem. Phys., 16, 9847–9862,Short summary
Using ozone and PM2.5 concentrations from the ACCMIP ensemble of chemistry-climate models for the four Representative Concentration Pathway scenarios (RCPs), together with projections of future population and baseline mortality rates, we quantify the human premature mortality impacts of future ambient air pollution in 2030, 2050 and 2100, relative to 2000 concentrations. We also estimate the global mortality burden of ozone and PM2.5 in 2000 and each future period.
Matthew Kasoar, Apostolos Voulgarakis, Jean-François Lamarque, Drew T. Shindell, Nicolas Bellouin, William J. Collins, Greg Faluvegi, and Kostas Tsigaridis
Atmos. Chem. Phys., 16, 9785–9804,Short summary
Computer models are our primary tool to investigate how fossil-fuel emissions are affecting the climate. Here, we used three different climate models to see how they simulate the response to removing sulfur dioxide emissions from China. We found that the models disagreed substantially on how large the climate effect is from the emissions in this region. This range of outcomes is concerning if scientists or policy makers have to rely on any one model when performing their own studies.
Yuqiang Zhang, Jared H. Bowden, Zachariah Adelman, Vaishali Naik, Larry W. Horowitz, Steven J. Smith, and J. Jason West
Atmos. Chem. Phys., 16, 9533–9548,Short summary
Reducing greenhouse gas (GHG) emissions can also improve air quality. We estimate the co-benefits of global GHG mitigation for US air quality in 2050 at fine resolution by downscaling from a previous global study. Foreign GHG mitigation under RCP4.5 contributes more to the US O3 reduction (76 % of the total) than domestic mitigation and contributes 26 % of the PM2.5 reduction. Therefore, the US gains significantly greater air quality co-benefits by coordinating GHG controls internationally.
Ryan Reynolds Neely III, Andrew J. Conley, Francis Vitt, and Jean-François Lamarque
Geosci. Model Dev., 9, 2459–2470,Short summary
We describe an updated scheme for prescribing stratospheric aerosol in the Community Earth System Model (CESM1). The inadequate response of the CESM1 to large volcanic disturbances to the stratospheric aerosol layer (such as the 1991 Pinatubo eruption) in comparison to observations motivates the need for a new parameterization. Simulations utilizing the new scheme successfully reproduce the observed global mean and local stratospheric temperature response to the Pinatubo eruption.
Nathan J. Chellman, Meredith G. Hastings, and Joseph R. McConnell
The Cryosphere Discuss.,
Revised manuscript not acceptedShort summary
This manuscript analyzes the changing sources of nitrate deposition to Greenland since 1760 CE using a dataset consisting of sub-seasonally resolved nitrogen isotopes of nitrate and source tracers. Correlations amongst ion concentration, source tracers, and the δ15N–NO3− provide evidence of the impact of biomass burning and fossil fuel combustion emissions of nitrogen oxides and suggest that oil combustion is the likely driver of increased nitrate concentration in Greenland ice since 1940 CE.
Borgar Aamaas, Terje K. Berntsen, Jan S. Fuglestvedt, Keith P. Shine, and Nicolas Bellouin
Atmos. Chem. Phys., 16, 7451–7468,
Naifang Bei, Guohui Li, Ru-Jin Huang, Junji Cao, Ning Meng, Tian Feng, Suixin Liu, Ting Zhang, Qiang Zhang, and Luisa T. Molina
Atmos. Chem. Phys., 16, 7373–7387,Short summary
Rapid industrialization and urbanization have caused severe air pollution in the Guanzhong basin, northwestern China with heavy haze events occurring frequently in recent winters. Due to frequent occurrence of unfavorable synoptic situations during wintertime, mitigation of emissions is the optimum approach to mitigate the air pollution in the Guanzhong basin.
Sarah A. Strode, Helen M. Worden, Megan Damon, Anne R. Douglass, Bryan N. Duncan, Louisa K. Emmons, Jean-Francois Lamarque, Michael Manyin, Luke D. Oman, Jose M. Rodriguez, Susan E. Strahan, and Simone Tilmes
Atmos. Chem. Phys., 16, 7285–7294,Short summary
We use global models to interpret trends in MOPITT observations of CO. Simulations with time-dependent emissions reproduce the observed trends over the eastern USA and Europe, suggesting that the emissions are reasonable for these regions. The simulations produce a positive trend over eastern China, contrary to the observed negative trend. This may indicate that the assumed emission trend over China is too positive. However, large variability in the overhead ozone column also contributes.
Kjetil S. Aas, Thorben Dunse, Emily Collier, Thomas V. Schuler, Terje K. Berntsen, Jack Kohler, and Bartłomiej Luks
The Cryosphere, 10, 1089–1104,Short summary
A high-resolution, coupled atmosphere--climatic mass balance (CMB) model is applied to Svalbard for the period 2003 to 2013. The mean CMB during this period is negative but displays large spatial and temporal variations. Comparison with observations on different scales shows a good overall model performance except for one particular glacier, where wind strongly affects the spatial patterns of CMB. The model also shows considerable sensitivity to model resolution, especially on local scales.
Simone Tilmes, Jean-Francois Lamarque, Louisa K. Emmons, Doug E. Kinnison, Dan Marsh, Rolando R. Garcia, Anne K. Smith, Ryan R. Neely, Andrew Conley, Francis Vitt, Maria Val Martin, Hiroshi Tanimoto, Isobel Simpson, Don R. Blake, and Nicola Blake
Geosci. Model Dev., 9, 1853–1890,Short summary
The state of the art Community Earth System Model, CESM1 CAM4-chem has been used to perform reference and sensitivity simulations as part of the Chemistry Climate Model Initiative (CCMI). Specifics of the model and details regarding the setup of the simulations are described. In additions, the main behavior of the model, including selected chemical species have been evaluated with climatological datasets. This paper is therefore a references for studies that use the provided model results.
Carly R. Tozer, Tessa R. Vance, Jason L. Roberts, Anthony S. Kiem, Mark A. J. Curran, and Andrew D. Moy
Hydrol. Earth Syst. Sci., 20, 1703–1717,Short summary
A 1013-year annual rainfall reconstruction was developed for the Williams River catchment in coastal eastern Australia, based on a linear relationship between sea salt deposition in East Antarctica and rainfall in eastern Australia. The reconstruction allows for the instrumental climate record (~ 100 years) to be assessed in the context of millennial climate variability, allowing for better characterisation of flood and drought risk.
Yunha Lee, Drew T. Shindell, Greg Faluvegi, and Rob W. Pinder
Atmos. Chem. Phys., 16, 5323–5342,Short summary
We studied the impact of US air quality (AQ) regulations and hypothetical CO2 reduction policy on public health and climate change. We find that AQ regulations are projected to have strong health benefits in the near future but result in a positive radiative forcing (RF), ~ 0.8 W m−2, over the USA. Under the US CO2 policy we find air quality co-benefits. However, despite CO2 reductions, it leads to overall positive RF (+0.22 W m−2 in 2055) over the USA mainly by lowering SO2 via less coal usage.
Rachael H. Rhodes, Xavier Faïn, Edward J. Brook, Joseph R. McConnell, Olivia J. Maselli, Michael Sigl, Jon Edwards, Christo Buizert, Thomas Blunier, Jérôme Chappellaz, and Johannes Freitag
Clim. Past, 12, 1061–1077,Short summary
Local artifacts in ice core methane data are superimposed on consistent records of past atmospheric variability. These artifacts are not related to past atmospheric history and care should be taken to avoid interpreting them as such. By investigating five polar ice cores from sites with different conditions, we relate isolated methane spikes to melt layers and decimetre-scale variations as "trapping signal" associated with a difference in timing of air bubble closure in adjacent firn layers.
Hongyu Liu, David B. Considine, Larry W. Horowitz, James H. Crawford, Jose M. Rodriguez, Susan E. Strahan, Megan R. Damon, Stephen D. Steenrod, Xiaojing Xu, Jules Kouatchou, Claire Carouge, and Robert M. Yantosca
Atmos. Chem. Phys., 16, 4641–4659,Short summary
We assess the utility of cosmogenic beryllium-7, a natural aerosol tracer, for evaluating cross-tropopause transport in global models. We show that model excessive cross-tropopause transport of beryllium-7 corresponds to overestimated stratospheric contribution to tropospheric ozone. We conclude that the observational constraints for beryllium-7 and observed beryllium-7 total deposition fluxes can be used routinely as a first-order assessment of cross-tropopause transport in global models.
Holly Winton, Andrew Bowie, Melita Keywood, Pier van der Merwe, and Ross Edwards
Atmos. Meas. Tech. Discuss.,
Revised manuscript not acceptedShort summary
Aerosols containing iron have been investigated over the remote Southern Ocean to constrain iron budgets in surface waters and related biological production. Protocols for the sampling of ambient air were used to assess the suitability of high-volume aerosol samplers for aerosol iron studies in pristine air masses. Significant evidence of airborne insect and local soil contamination was detected in exposure blank filters. Suggestions for future aerosol iron sampling in clean air are provided.
Min Zhong, Eri Saikawa, Yang Liu, Vaishali Naik, Larry W. Horowitz, Masayuki Takigawa, Yu Zhao, Neng-Huei Lin, and Elizabeth A. Stone
Geosci. Model Dev., 9, 1201–1218,Short summary
Large discrepancies exist among emission inventories (e.g., REAS and EDGAR) at the provincial level in China. We use WRF-Chem to evaluate the impact of the difference in existing emission inventories and find that emissions inputs significantly affect our air pollutant simulation results. Our study highlights the importance of constraining emissions at the provincial level for regional air quality modeling over East Asia.
Michael Sigl, Tyler J. Fudge, Mai Winstrup, Jihong Cole-Dai, David Ferris, Joseph R. McConnell, Ken C. Taylor, Kees C. Welten, Thomas E. Woodruff, Florian Adolphi, Marion Bisiaux, Edward J. Brook, Christo Buizert, Marc W. Caffee, Nelia W. Dunbar, Ross Edwards, Lei Geng, Nels Iverson, Bess Koffman, Lawrence Layman, Olivia J. Maselli, Kenneth McGwire, Raimund Muscheler, Kunihiko Nishiizumi, Daniel R. Pasteris, Rachael H. Rhodes, and Todd A. Sowers
Clim. Past, 12, 769–786,Short summary
Here we present a chronology (WD2014) for the upper part (0–2850 m; 31.2 ka BP) of the West Antarctic Ice Sheet (WAIS) Divide ice core, which is based on layer counting of distinctive annual cycles preserved in the elemental, chemical and electrical conductivity records. We validated the chronology by comparing it to independent high-accuracy, absolutely dated chronologies. Given its demonstrated high accuracy, WD2014 can become a reference chronology for the Southern Hemisphere.
James Hansen, Makiko Sato, Paul Hearty, Reto Ruedy, Maxwell Kelley, Valerie Masson-Delmotte, Gary Russell, George Tselioudis, Junji Cao, Eric Rignot, Isabella Velicogna, Blair Tormey, Bailey Donovan, Evgeniya Kandiano, Karina von Schuckmann, Pushker Kharecha, Allegra N. Legrande, Michael Bauer, and Kwok-Wai Lo
Atmos. Chem. Phys., 16, 3761–3812,Short summary
We use climate simulations, paleoclimate data and modern observations to infer that continued high fossil fuel emissions will yield cooling of Southern Ocean and North Atlantic surfaces, slowdown and shutdown of SMOC & AMOC, increasingly powerful storms and nonlinear sea level rise reaching several meters in 50–150 years, effects missed in IPCC reports because of omission of ice sheet melt and an insensitivity of most climate models, likely due to excessive ocean mixing.
N. I. Kristiansen, A. Stohl, D. J. L. Olivié, B. Croft, O. A. Søvde, H. Klein, T. Christoudias, D. Kunkel, S. J. Leadbetter, Y. H. Lee, K. Zhang, K. Tsigaridis, T. Bergman, N. Evangeliou, H. Wang, P.-L. Ma, R. C. Easter, P. J. Rasch, X. Liu, G. Pitari, G. Di Genova, S. Y. Zhao, Y. Balkanski, S. E. Bauer, G. S. Faluvegi, H. Kokkola, R. V. Martin, J. R. Pierce, M. Schulz, D. Shindell, H. Tost, and H. Zhang
Atmos. Chem. Phys., 16, 3525–3561,Short summary
Processes affecting aerosol removal from the atmosphere are not fully understood. In this study we investigate to what extent atmospheric transport models can reproduce observed loss of aerosols. We compare measurements of radioactive isotopes, that attached to ambient sulfate aerosols during the 2011 Fukushima nuclear accident, to 19 models using identical emissions. Results indicate aerosol removal that is too fast in most models, and apply to aerosols that have undergone long-range transport.
Miriam Elser, Ru-Jin Huang, Robert Wolf, Jay G. Slowik, Qiyuan Wang, Francesco Canonaco, Guohui Li, Carlo Bozzetti, Kaspar R. Daellenbach, Yu Huang, Renjian Zhang, Zhengqiang Li, Junji Cao, Urs Baltensperger, Imad El-Haddad, and André S. H. Prévôt
Atmos. Chem. Phys., 16, 3207–3225,Short summary
This work represents the first online chemical characterization of the PM2.5 using a high-resolution time-of flight aerosol mass spectrometer during extreme haze events China. The application of novel source apportionment techniques allowed for an improved identification and quantification of the sources of organic aerosols. The main sources and processes driving the extreme haze events are assessed.
Stig B. Dalsøren, Cathrine L. Myhre, Gunnar Myhre, Angel J. Gomez-Pelaez, Ole A. Søvde, Ivar S. A. Isaksen, Ray F. Weiss, and Christina M. Harth
Atmos. Chem. Phys., 16, 3099–3126,Short summary
Methane is a key greenhouse gas. Observations at surface sites show a more than 10 % increase over the period 1984–2012. Using an atmospheric model we calculate a growth in the atmospheric chemical methane loss the last decades. Without this, the rise in atmospheric methane would have been even higher. The model reproduces trends and short-term variations in observation data. However, some discrepancies in model performance question the accuracy in estimates of emission increases in Asia.
Tessa R. Vance, Jason L. Roberts, Andrew D. Moy, Mark A. J. Curran, Carly R. Tozer, Ailie J. E. Gallant, Nerilie J. Abram, Tas D. van Ommen, Duncan A. Young, Cyril Grima, Don D. Blankenship, and Martin J. Siegert
Clim. Past, 12, 595–610,Short summary
This study details a systematic approach to finding a new high-resolution East Antarctic ice core site. The study initially outlines seven criteria that a new site must fulfil, encompassing specific accumulation, ice dynamics and atmospheric circulation aspects. We then use numerous techniques including Antarctic surface mass balance syntheses, ground-truthing of satellite data by airborne radar surveys and reanalysis products to pinpoint promising regions.
Shipeng Zhang, Minghuai Wang, Steven J. Ghan, Aijun Ding, Hailong Wang, Kai Zhang, David Neubauer, Ulrike Lohmann, Sylvaine Ferrachat, Toshihiko Takeamura, Andrew Gettelman, Hugh Morrison, Yunha Lee, Drew T. Shindell, Daniel G. Partridge, Philip Stier, Zak Kipling, and Congbin Fu
Atmos. Chem. Phys., 16, 2765–2783,Short summary
The variation of aerosol indirect effects (AIE) in several climate models is investigated across different dynamical regimes. Regimes with strong large-scale ascent are shown to be as important as stratocumulus regimes in studying AIE. AIE over regions with high monthly large-scale surface precipitation rate contributes the most to the total aerosol indirect forcing. These results point to the need to reduce the uncertainty in AIE in different dynamical regimes.
G. M. Wolfe, J. Kaiser, T. F. Hanisco, F. N. Keutsch, J. A. de Gouw, J. B. Gilman, M. Graus, C. D. Hatch, J. Holloway, L. W. Horowitz, B. H. Lee, B. M. Lerner, F. Lopez-Hilifiker, J. Mao, M. R. Marvin, J. Peischl, I. B. Pollack, J. M. Roberts, T. B. Ryerson, J. A. Thornton, P. R. Veres, and C. Warneke
Atmos. Chem. Phys., 16, 2597–2610,Short summary
This study uses airborne trace gas observations acquired over the southeast US to examine how both natural (isoprene) and anthropogenic (NOx) emissions influence the production of formaldehyde (HCHO). We find a 3-fold increase in HCHO yield between rural and polluted environments. State-of-the-science chemical mechanisms are generally able to reproduce this behavior. These results add confidence to global hydrocarbon emission inventories constrained by spaceborne HCHO observations.
Zak Kipling, Philip Stier, Colin E. Johnson, Graham W. Mann, Nicolas Bellouin, Susanne E. Bauer, Tommi Bergman, Mian Chin, Thomas Diehl, Steven J. Ghan, Trond Iversen, Alf Kirkevåg, Harri Kokkola, Xiaohong Liu, Gan Luo, Twan van Noije, Kirsty J. Pringle, Knut von Salzen, Michael Schulz, Øyvind Seland, Ragnhild B. Skeie, Toshihiko Takemura, Kostas Tsigaridis, and Kai Zhang
Atmos. Chem. Phys., 16, 2221–2241,Short summary
The vertical distribution of atmospheric aerosol is an important factor in its effects on climate. In this study we use a sophisticated model of the many interacting processes affecting aerosol in the atmosphere to show that the vertical distribution is typically dominated by only a few of these processes. Constraining these physical processes may help to reduce the large differences between models. However, the important processes are not always the same for different types of aerosol.
Kai Zhang, Chun Zhao, Hui Wan, Yun Qian, Richard C. Easter, Steven J. Ghan, Koichi Sakaguchi, and Xiaohong Liu
Geosci. Model Dev., 9, 607–632,Short summary
A sub-grid treatment based on Weibull distribution is introduced to CAM5 to take into account the impact of unresolved variability of surface wind speed on sea salt and dust emissions. Simulations show that sub-grid wind variability has relatively small impacts on the global mean sea salt emissions, but considerable influence on dust emissions. Dry convective eddies and mesoscale flows associated with complex topography are the major causes of dust emission enhancement.
F. Paulot, P. Ginoux, W. F. Cooke, L. J. Donner, S. Fan, M.-Y. Lin, J. Mao, V. Naik, and L. W. Horowitz
Atmos. Chem. Phys., 16, 1459–1477,Short summary
We characterize the sensitivity of NO3 optical depth (OD) to both the sources of its precursors (NH3 and HNO3) and to its surface sinks. Uncertainties in the heterogeneous chemistry of HNO3 and the near-surface volatilization of NH4NO3 can cause up to 25 % difference in the global NO3 OD. Simulated NO3 OD increases little (< 30 %) in response to changes in emissions (2010 to 2050). Better constraints on the tropical flux of NH3 into the free troposphere are needed to improve estimates of NO3 OD.
X. Liu, P.-L. Ma, H. Wang, S. Tilmes, B. Singh, R. C. Easter, S. J. Ghan, and P. J. Rasch
Geosci. Model Dev., 9, 505–522,Short summary
In this study, we describe and evaluate a new four-mode version of the Modal Aerosol Module (MAM4) in the Community Atmosphere Model version 5 (CAM5). Compared to the current three-mode version of MAM in CAM5, MAM4 significantly improves the simulation of seasonal variation of BC concentrations in the polar regions, by increasing the BC concentrations in all seasons and particularly in cold seasons.
A. Spolaor, T. Opel, J. R. McConnell, O. J. Maselli, G. Spreen, C. Varin, T. Kirchgeorg, D. Fritzsche, A. Saiz-Lopez, and P. Vallelonga
The Cryosphere, 10, 245–256,Short summary
The role of sea ice in the Earth climate system is still under debate, although it is known to influence albedo, ocean circulation, and atmosphere-ocean heat and gas exchange. Here we present a reconstruction of 1950 to 1998 AD sea ice in the Laptev Sea based on the Akademii Nauk ice core (Severnaya Zemlya, Russian Arctic) and halogen measurements. The results suggest a connection between bromine and sea ice, as well as a connection between iodine concentration in snow and summer sea ice.
C. S. M. Turney, C. J. Fogwill, A. R. Klekociuk, T. D. van Ommen, M. A. J. Curran, A. D. Moy, and J. G. Palmer
The Cryosphere, 9, 2405–2415,Short summary
Recent trends in ocean circulation, sea ice and climate over the Southern Ocean and Antarctica are highly complex. Here we report a new snow core from the South Pole alongside reanalysis of 20th century global atmospheric circulation. We demonstrate for the first time that atmospheric pressure anomalies in the mid-latitudes act as "gatekeepers" to meridional exchange over continental Antarctica, modulated by the tropical Pacific, with potentially significant impacts on surface mass balance.
J. He, Y. Zhang, S. Tilmes, L. Emmons, J.-F. Lamarque, T. Glotfelty, A. Hodzic, and F. Vitt
Geosci. Model Dev., 8, 3999–4025,Short summary
The global simulations with CB05_GE and MOZART-4x predict similar chemical profiles for major gases compared to aircraft measurements, with better agreement for the NOy profile by CB05_GE. The SOA concentrations of SOA at four sites in CONUS and organic carbon over the IMPROVE sites are better predicted by MOZART-4x. The two simulations result in a global average difference of 0.5W m-2 in simulated shortwave cloud radiative forcing, with up to 13.6W m-2 over subtropical regions.
Y. Zheng, N. Unger, A. Hodzic, L. Emmons, C. Knote, S. Tilmes, J.-F. Lamarque, and P. Yu
Atmos. Chem. Phys., 15, 13487–13506,Short summary
Nitrogen oxides (NOx) play an important but complex role in secondary organic aerosol (SOA) formation. In this study we update the SOA scheme in a global 3-D chemistry-climate model by implementing a 4-product volatility basis set (VBS) framework with NOx-dependent yields and simplified aging parameterizations. We find that the SOA decrease in response to a 50% reduction in anthropogenic NOx emissions is limited due to the buffering in different chemical pathways.
K. Thayer-Calder, A. Gettelman, C. Craig, S. Goldhaber, P. A. Bogenschutz, C.-C. Chen, H. Morrison, J. Höft, E. Raut, B. M. Griffin, J. K. Weber, V. E. Larson, M. C. Wyant, M. Wang, Z. Guo, and S. J. Ghan
Geosci. Model Dev., 8, 3801–3821,Short summary
This study evaluates a unified cloud parameterization and a Monte Carlo microphysics interface that is implemented in CAM v5.3. We show mean climate and tropical variability results from global simulations. The model has a degradation in precipitation skill but improvements in shortwave cloud forcing, liquid water path, long-wave cloud forcing, precipitable water, and tropical wave simulation. We also show estimation of computational expense and sensitivity to number of subcolumns.
Q. Y. Wang, R.-J. Huang, J. J. Cao, X. X. Tie, H. Y. Ni, Y. Q. Zhou, Y. M. Han, T. F. Hu, C. S. Zhu, T. Feng, N. Li, and J. D. Li
Atmos. Chem. Phys., 15, 13059–13069,Short summary
An intensive campaign was conducted at the Qinghai-Tibetan Plateau using a ground-based single particle soot photometer and a photoacoustic extinctiometer. Significant enhancements of rBC loadings and number fraction of coated rBC were observed during the pollution episode. Biomass burning from N. India is determined to be an important potential source influencing the northeastern Qinghai-Tibetan Plateau. The rBC mixing state is important in determining absorption during the pollution episode.
D. M. Westervelt, L. W. Horowitz, V. Naik, J.-C. Golaz, and D. L. Mauzerall
Atmos. Chem. Phys., 15, 12681–12703,Short summary
Decreases in aerosols over the 21st century as projected by the Representative Concentration Pathways (RCPs) lead to increases up to 0.5 - 1 ºC in global temperature and up to 0.05 - 0.1 mm/day in global precipitation, depending strongly on present-day aerosol radiative forcing. In East Asia, future aerosol decreases could be responsible for 10-20% of the total temperature increase (30-40% with strong present-day aerosol forcing), even under the high greenhouse gas emissions scenario (RCP8.5).
J. L. Lieser, M. A. J. Curran, A. R. Bowie, A. T. Davidson, S. J. Doust, A. D. Fraser, B. K. Galton-Fenzi, R. A. Massom, K. M. Meiners, J. Melbourne-Thomas, P. A. Reid, P. G. Strutton, T. R. Vance, M. Vancoppenolle, K. J. Westwood, and S. W. Wright
The Cryosphere Discuss.,
Revised manuscript has not been submitted
D. Singh, M. G. Flanner, and J. Perket
The Cryosphere, 9, 2057–2070,Short summary
Our work quantifies the effect of snow/ice cover on Earth's top-of-atmosphere solar energy budget. We used higher resolution MODIS data, combined with microwave retrievals of snow presence and radiative kernels produced from 4 different models for Cryosphere Radiative Effect (CrRE) estimation. We have estimated a global land-based CrRE of about -2.6Wm-2 during 2001-2013, with about 59% of the effect originating from Antarctica. We were also be able to resolve contribution from mountain glaciers.
P. Kuipers Munneke, S. R. M. Ligtenberg, B. P. Y. Noël, I. M. Howat, J. E. Box, E. Mosley-Thompson, J. R. McConnell, K. Steffen, J. T. Harper, S. B. Das, and M. R. van den Broeke
The Cryosphere, 9, 2009–2025,Short summary
The snow layer on top of the Greenland Ice Sheet is changing: it is thickening in the high and cold interior due to increased snowfall, while it is thinning around the margins. The marginal thinning is caused by compaction, and by more melt. This knowledge is important: there are satellites that measure volume change of the ice sheet. It can be caused by increased ice discharge, or by compaction of the snow layer. Here, we quantify the latter, so that we can translate volume to mass change.
A. Ellis, R. Edwards, M. Saunders, R. K. Chakrabarty, R. Subramanian, A. van Riessen, A. M. Smith, D. Lambrinidis, L. J. Nunes, P. Vallelonga, I. D. Goodwin, A. D. Moy, M. A. J. Curran, and T. D. van Ommen
Atmos. Meas. Tech., 8, 3959–3969,Short summary
Black carbon is an important environmental pollutant, and the structure and composition of these particles are important to measuring their affect on the climate. Historical records of black carbon emissions are stored in polar ice. This paper details a new method to study black carbon preserved in Antarctic ice cores. By combining filtration to concentrate the particles and electron microscopy to characterize them, this method opens up a new avenue to study the history of our atmosphere.
M. Gil-Ojeda, M. Navarro-Comas, L. Gómez-Martín, J. A. Adame, A. Saiz-Lopez, C. A. Cuevas, Y. González, O. Puentedura, E. Cuevas, J.-F. Lamarque, D. Kinninson, and S. Tilmes
Atmos. Chem. Phys., 15, 10567–10579,Short summary
The NO2 seasonal evolution in the free troposphere (FT) has been established for the first time, based on a remote sensing technique (MAXDOAS) and thus avoiding the problems of the local pollution of in situ instruments. A clear seasonality has been found, with background levels of 20-40pptv. Evidence has been found on fast, direct injection of surface air into the free troposphere. This result might have implications on the FT distribution of halogens and other species with marine sources.
J. L. Schnell, M. J. Prather, B. Josse, V. Naik, L. W. Horowitz, P. Cameron-Smith, D. Bergmann, G. Zeng, D. A. Plummer, K. Sudo, T. Nagashima, D. T. Shindell, G. Faluvegi, and S. A. Strode
Atmos. Chem. Phys., 15, 10581–10596,Short summary
We test global chemistry--climate models in their ability to simulate present-day surface ozone. Models are tested against observed hourly ozone from 4217 stations in North America and Europe that are averaged over 1°x1° grid cells. Using novel metrics, we find most models match the shape but not the amplitude of regional summertime diurnal and annual cycles and match the pattern but not the magnitude of summer ozone enhancement. Most also match the observed distribution of extreme episode sizes
A. Stohl, B. Aamaas, M. Amann, L. H. Baker, N. Bellouin, T. K. Berntsen, O. Boucher, R. Cherian, W. Collins, N. Daskalakis, M. Dusinska, S. Eckhardt, J. S. Fuglestvedt, M. Harju, C. Heyes, Ø. Hodnebrog, J. Hao, U. Im, M. Kanakidou, Z. Klimont, K. Kupiainen, K. S. Law, M. T. Lund, R. Maas, C. R. MacIntosh, G. Myhre, S. Myriokefalitakis, D. Olivié, J. Quaas, B. Quennehen, J.-C. Raut, S. T. Rumbold, B. H. Samset, M. Schulz, Ø. Seland, K. P. Shine, R. B. Skeie, S. Wang, K. E. Yttri, and T. Zhu
Atmos. Chem. Phys., 15, 10529–10566,Short summary
This paper presents a summary of the findings of the ECLIPSE EU project. The project has investigated the climate and air quality impacts of short-lived climate pollutants (especially methane, ozone, aerosols) and has designed a global mitigation strategy that maximizes co-benefits between air quality and climate policy. Transient climate model simulations allowed quantifying the impacts on temperature (e.g., reduction in global warming by 0.22K for the decade 2041-2050) and precipitation.
L. Zhang, D. K. Henze, G. A. Grell, G. R. Carmichael, N. Bousserez, Q. Zhang, O. Torres, C. Ahn, Z. Lu, J. Cao, and Y. Mao
Atmos. Chem. Phys., 15, 10281–10308,Short summary
We attempt to reduce uncertainties in BC emissions and improve BC model simulations by developing top-down, spatially resolved, estimates of BC emissions through assimilation of OMI observations of aerosol absorption optical depth (AAOD) with the GEOS-Chem model and its adjoint for April and October of 2006. Despite the limitations and uncertainties, using OMI AAOD to constrain BC sources we are able to improve model representation of BC distributions, particularly over China.
K. P. Shine, R. P. Allan, W. J. Collins, and J. S. Fuglestvedt
Earth Syst. Dynam., 6, 525–540,Short summary
Emissions due to human activity impact on rainfall. This impact depends on the properties of the gases or particles that are emitted. This paper uses improved understanding of relevant processes to produce a new measure, called the Global Precipitation-change Potential, which allows a direct comparison of the effect of different emissions on global-mean rainfall. Carbon dioxide, in the years following its emission, is shown to be less effective than methane emissions at causing rainfall change.