Articles | Volume 19, issue 22
22 Nov 2019
Research article | 22 Nov 2019
Novel approaches to improve estimates of short-lived halocarbon emissions during summer from the Southern Ocean using airborne observations
Elizabeth Asher et al.
No articles found.
Dustin Roten, John C. Lin, Lewis Kunik, Derek Mallia, Dien Wu, Tomohiro Oda, and Eric A. Kort
Atmos. Chem. Phys. Discuss.,
Preprint under review for ACPShort summary
The systems used to monitor carbon dioxide (CO2) emissions from urban areas provides a means to observe and quantify emissions reductions from policy-related reduction efforts. Space-based instruments, such as NASA's Orbiting Carbon Observatory-3 (OCO-3), provides detailed "snapshots" of CO2 emissions from many megacities around the world. This work quantifies the amount of emission "information" contained in these snapshots and uses this information to update previous estimates of urban CO2.
Helen M. Worden, Gene L. Francis, Susan S. Kulawik, Kevin W. Bowman, Karen Cady-Pereira, Dejian Fu, Jennifer D. Hegarty, Valentin Kantchev, Ming Luo, Vivienne H. Payne, John R. Worden, Róisín Commane, and Kathryn McKain
Atmos. Meas. Tech. Discuss.,
Preprint under review for AMTShort summary
Satellite observations of global carbon monoxide (CO) are essential for understanding atmospheric chemistry and pollution sources. This paper describes a new data product using radiance measurements from the Cross-track Infrared Sounder (CrIS) instrument on the Suomi National Polar-orbiting Partnership (SNPP) satellite that provides vertical profiles of CO from single field of view observations. We show how these satellite CO profiles compare to aircraft observations and evaluate their biases.
Pierre Friedlingstein, Matthew W. Jones, Michael O'Sullivan, Robbie M. Andrew, Dorothee C. E. Bakker, Judith Hauck, Corinne Le Quéré, Glen P. Peters, Wouter Peters, Julia Pongratz, Stephen Sitch, Josep G. Canadell, Philippe Ciais, Rob B. Jackson, Simone R. Alin, Peter Anthoni, Nicholas R. Bates, Meike Becker, Nicolas Bellouin, Laurent Bopp, Thi Tuyet Trang Chau, Frédéric Chevallier, Louise P. Chini, Margot Cronin, Kim I. Currie, Bertrand Decharme, Laique M. Djeutchouang, Xinyu Dou, Wiley Evans, Richard A. Feely, Liang Feng, Thomas Gasser, Dennis Gilfillan, Thanos Gkritzalis, Giacomo Grassi, Luke Gregor, Nicolas Gruber, Özgür Gürses, Ian Harris, Richard A. Houghton, George C. Hurtt, Yosuke Iida, Tatiana Ilyina, Ingrid T. Luijkx, Atul Jain, Steve D. Jones, Etsushi Kato, Daniel Kennedy, Kees Klein Goldewijk, Jürgen Knauer, Jan Ivar Korsbakken, Arne Körtzinger, Peter Landschützer, Siv K. Lauvset, Nathalie Lefèvre, Sebastian Lienert, Junjie Liu, Gregg Marland, Patrick C. McGuire, Joe R. Melton, David R. Munro, Julia E. M. S. Nabel, Shin-Ichiro Nakaoka, Yosuke Niwa, Tsuneo Ono, Denis Pierrot, Benjamin Poulter, Gregor Rehder, Laure Resplandy, Eddy Robertson, Christian Rödenbeck, Thais M. Rosan, Jörg Schwinger, Clemens Schwingshackl, Roland Séférian, Adrienne J. Sutton, Colm Sweeney, Toste Tanhua, Pieter P. Tans, Hanqin Tian, Bronte Tilbrook, Francesco Tubiello, Guido R. van der Werf, Nicolas Vuichard, Chisato Wada, Rik Wanninkhof, Andrew J. Watson, David Willis, Andrew J. Wiltshire, Wenping Yuan, Chao Yue, Xu Yue, Sönke Zaehle, and Jiye Zeng
Earth Syst. Sci. Data, 14, 1917–2005,Short summary
The Global Carbon Budget 2021 describes the data sets and methodology used to quantify the emissions of carbon dioxide and their partitioning among the atmosphere, land, and ocean. These living data are updated every year to provide the highest transparency and traceability in the reporting of CO2, the key driver of climate change.
Jadwiga Richter, Daniele Visioni, Douglas MacMartin, David Bailey, Nan Rosenbloom, Walker Lee, Mari Tye, and Jean-Francois Lamarque
Solar climate intervention using stratospheric aerosol injection is a proposed method of reducing global mean temperatures to reduce some of the consequences of climate change. We present here a new modeling protocol and an ensemble of simulations using one of the most comprehensive Earth system models: the Assessing Responses and Impacts of Solar climate intervention on the Earth system with stratospheric aerosol injection (ARISE-SAI) simulations.
Merritt Deeter, Gene Francis, John Gille, Debbie Mao, Sara Martínez-Alonso, Helen Worden, Dan Ziskin, James Drummond, Róisín Commane, Glenn Diskin, and Kathryn McKain
Atmos. Meas. Tech., 15, 2325–2344,Short summary
The MOPITT (Measurements of Pollution in the Troposphere) satellite instrument uses remote sensing to obtain retrievals (measurements) of carbon monoxide (CO) in the atmosphere. This paper describes the latest MOPITT data product, Version 9. Globally, the number of daytime MOPITT retrievals over land has increased by 30 %–40 % compared to the previous product. The reported improvements in the MOPITT product should benefit a wide variety of applications including studies of pollution sources.
Lucien Froidevaux, Douglas E. Kinnison, Michelle L. Santee, Luis F. Millán, Nathaniel J. Livesey, William G. Read, Charles G. Bardeen, John J. Orlando, and Ryan A. Fuller
Atmos. Chem. Phys., 22, 4779–4799,Short summary
We analyze satellite-derived distributions of chlorine monoxide (ClO) and hypochlorous acid (HOCl) in the upper atmosphere. For 2005–2020, from 50°S to 50°N and over ~30 to 45 km, ClO and HOCl decreased by −0.7 % and −0.4 % per year, respectively. A detailed model of chemistry and dynamics agrees with the results. These decreases confirm the effectiveness of the 1987 Montreal Protocol, which limited emissions of chlorine- and bromine-containing source gases, in order to protect the ozone layer.
Simone Tilmes, Daniele Visioni, Andy Jones, James Haywood, Roland Séférian, Pierre Nabat, Olivier Boucher, Ewa Monica Bednarz, and Ulrike Niemeier
Atmos. Chem. Phys., 22, 4557–4579,Short summary
This study assesses the impacts of climate interventions, using stratospheric sulfate aerosol and solar dimming on stratospheric ozone, based on three Earth system models with interactive stratospheric chemistry. The climate interventions have been applied to a high emission (baseline) scenario in order to reach global surface temperatures of a medium emission scenario. We find significant increases and decreases in total column ozone, depending on regions and seasons.
Hisahiro Takashima, Yugo Kanaya, Saki Kato, Martina M. Friedrich, Michel Van Roozendael, Fumikazu Taketani, Takuma Miyakawa, Yuichi Komazaki, Carlos A. Cuevas, Alfonso Saiz-Lopez, and Takashi Sekiya
Atmos. Chem. Phys., 22, 4005–4018,Short summary
We have undertaken atmospheric iodine monoxide (IO) observations in the global marine boundary layer with a wide latitudinal coverage and sea surface temperature (SST) range. We conclude that atmospheric iodine is abundant over the Western Pacific warm pool, appearing as an iodine fountain, where ozone (O3) minima occur. Our study also found negative correlations between IO and O3 concentrations over IO maxima, which requires reconsideration of the initiation process of halogen activation.
Stephen Gerald Yeager, Nan Rosenbloom, Anne A. Glanville, Xian Wu, Isla Simpson, Hui Li, Maria J. Molina, Kristen Krumhardt, Samuel Mogen, Keith Lindsay, Danica Lombardozzi, Will Wieder, Who Myung Kim, Jadwiga H. Richter, Matthew Long, Gokhan Danabasoglu, David Bailey, Marika Holland, Nicole Lovenduski, and Warren G. Strand
Geosci. Model Dev. Discuss.,
Preprint under review for GMDShort summary
The natural environment changes over a range of time and space scales and some of these changes are predictable in advance. Short-term weather forecasts are most familiar to many, but recent work has shown that it is possible to generate useful predictions several seasons or even a decade in advance. This study focuses on predictions over intermediate timescales (up to 24 months in advance) and shows that there is promising potential to forecast a myriad of changes in the natural world.
Mari R. Tye, Katherine Dagon, Maria J. Molina, Jadwiga H. Richter, Daniele Visioni, Ben Kravitz, Claudia Tebaldi, and Simone Tilmes
We examined the potential effect of stratospheric aerosol injections (SAI) on extreme temperature and precipitation. SAI may cause daytime temperatures to cool but nighttime to warm. Daytime cooling may occur in all seasons across the globe, with largest decreases in the summer. In contrast, nighttime warming may be greatest at high latitudes in the winter. SAI may reduce the frequency and intensity of extreme rainfall. The combined changes may exacerbate drying over parts of the global South.
Andy Jones, Jim M. Haywood, Adam A. Scaife, Olivier Boucher, Matthew Henry, Ben Kravitz, Thibaut Lurton, Pierre Nabat, Ulrike Niemeier, Roland Séférian, Simone Tilmes, and Daniele Visioni
Atmos. Chem. Phys., 22, 2999–3016,Short summary
Simulations by six Earth-system models of geoengineering by introducing sulfuric acid aerosols into the tropical stratosphere are compared. A robust impact on the northern wintertime North Atlantic Oscillation is found, exacerbating precipitation reduction over parts of southern Europe. In contrast, the models show no consistency with regard to impacts on the Quasi-Biennial Oscillation, although results do indicate a risk that the oscillation could become locked into a permanent westerly phase.
Lei Hu, Stephen A. Montzka, Fred Moore, Eric Hintsa, Geoff Dutton, M. Carolina Siso, Kirk Thoning, Robert W. Portmann, Kathryn McKain, Colm Sweeney, Isaac Vimont, David Nance, Bradley Hall, and Steven Wofsy
Atmos. Chem. Phys., 22, 2891–2907,Short summary
The unexpected increase in CFC-11 emissions between 2012 and 2017 resulted in concerns about delaying the stratospheric ozone recovery. Although the subsequent decline of CFC-11 emissions indicated a mitigation in part to this problem, the regions fully responsible for these large emission changes were unclear. Here, our new estimate, based on atmospheric measurements from two global campaigns and from NOAA, suggests Asia primarily contributed to the global CFC-11 emission rise during 2012–2017.
Sara Martinez-Alonso, Ilse Aben, Bianca C. Baier, Tobias Borsdorff, Merritt N. Deeter, Kathryn McKain, Colm Sweeney, and Helen Worden
Atmos. Meas. Tech. Discuss.,
Preprint under review for AMTShort summary
AirCore is a novel balloon sampling system that can measure, among others, vertical profiles of carbon monoxide (CO) from 25–30 km of altitude to near the surface. Our analyses of AirCore and satellite CO data show that: AirCore profiles are suited for satellite data validation, the use of shorter aircraft vertical profiles in satellite validation results in small errors (1–3 percent points) mostly at 300 hPa and above, and the error introduced by clouds in TROPOMI land data is small (1–2 %).
Matthias Schneider, Benjamin Ertl, Christopher J. Diekmann, Farahnaz Khosrawi, Andreas Weber, Frank Hase, Michael Höpfner, Omaira E. García, Eliezer Sepúlveda, and Douglas Kinnison
Earth Syst. Sci. Data, 14, 709–742,Short summary
We present atmospheric H2O, HDO / H2O ratio, N2O, CH4, and HNO3 data generated by the MUSICA IASI processor using thermal nadir spectra measured by the IASI satellite instrument. The data have global daily coverage and are available for the period between October 2014 and June 2021. Multiple possibilities of data reuse are offered by providing each individual data product together with information about retrieval settings and the products' uncertainty and vertical representativeness.
Zhiyuan Gao, Nicolas-Xavier Geilfus, Alfonso Saiz-Lopez, and Feiyue Wang
Atmos. Chem. Phys., 22, 1811–1824,Short summary
Every spring in the Arctic, a series of photochemical events occur over the ice-covered ocean, known as bromine explosion events, ozone depletion events, and mercury depletion events. Here we report the re-creation of these events at an outdoor sea ice facility in Winnipeg, Canada, far away from the Arctic. The success provides a new platform with new opportunities to uncover fundamental mechanisms of these Arctic springtime phenomena and how they may change in a changing climate.
Yanan Zhao, Dennis Booge, Christa A. Marandino, Cathleen Schlundt, Astrid Bracher, Elliot L. Atlas, Jonathan Williams, and Hermann W. Bange
Biogeosciences, 19, 701–714,Short summary
We present here, for the first time, simultaneously measured dimethylsulfide (DMS) seawater concentrations and DMS atmospheric mole fractions from the Peruvian upwelling region during two cruises in December 2012 and October 2015. Our results indicate low oceanic DMS concentrations and atmospheric DMS molar fractions in surface waters and the atmosphere, respectively. In addition, the Peruvian upwelling region was identified as an insignificant source of DMS emissions during both periods.
Daniele Visioni, Simone Tilmes, Charles Bardeen, Michael Mills, Douglas G. MacMartin, Ben Kravitz, and Jadwiga H. Richter
Atmos. Chem. Phys., 22, 1739–1756,Short summary
Aerosols are simulated in a simplified way in climate models: in the model analyzed here, they are represented in every grid as described by three simple logarithmic distributions, mixing all different species together. The size can evolve when new particles are formed, particles merge together to create a larger one or particles are deposited to the surface. This approximation normally works fairly well. Here we show however that when large amounts of sulfate are simulated, there are problems.
Ka Ming Fung, Colette L. Heald, Jesse H. Kroll, Siyuan Wang, Duseong S. Jo, Andrew Gettelman, Zheng Lu, Xiaohong Liu, Rahul A. Zaveri, Eric C. Apel, Donald R. Blake, Jose-Luis Jimenez, Pedro Campuzano-Jost, Patrick R. Veres, Timothy S. Bates, John E. Shilling, and Maria Zawadowicz
Atmos. Chem. Phys., 22, 1549–1573,Short summary
Understanding the natural aerosol burden in the preindustrial era is crucial for us to assess how atmospheric aerosols affect the Earth's radiative budgets. Our study explores how a detailed description of dimethyl sulfide (DMS) oxidation (implemented in the Community Atmospheric Model version 6 with chemistry, CAM6-chem) could help us better estimate the present-day and preindustrial concentrations of sulfate and other relevant chemicals, as well as the resulting aerosol radiative impacts.
Min Huang, James H. Crawford, Gregory R. Carmichael, Kevin W. Bowman, Sujay V. Kumar, and Colm Sweeney
Atmos. Chem. Phys. Discuss.,
Preprint under review for ACPShort summary
This study demonstrates that, ozone dry deposition modeling can be improved by revising the model's dry deposition parameterizations to better represent the effects of environmental conditions including the soil moisture fields. Applying satellite soil moisture data assimilation is shown to also have added value. Such advancements in coupled modeling and data assimilation can benefit the assessments of ozone impacts on human and vegetation health.
Jennifer D. Hegarty, Karen E. Cady-Pereira, Vivienne H. Payne, Susan S. Kulawik, John R. Worden, Valentin Kantchev, Helen M. Worden, Kathryn McKain, Jasna V. Pittman, Róisín Commane, Bruce C. Daube Jr., and Eric A. Kort
Atmos. Meas. Tech., 15, 205–223,Short summary
Carbon monoxide (CO) is produced by combustion of substances such as fossil fuels and plays an important role in atmospheric pollution and climate. We evaluated estimates of atmospheric CO derived from outgoing radiation measurements of the Atmospheric Infrared Sounder (AIRS) on a satellite orbiting the Earth against CO measurements from aircraft to show that these satellite measurements are reliable for continuous global monitoring of atmospheric CO concentrations.
Nicholas A. Davis, Patrick Callaghan, Isla R. Simpson, and Simone Tilmes
Atmos. Chem. Phys., 22, 197–214,Short summary
Specified dynamics schemes attempt to constrain the atmospheric circulation in a climate model to isolate the role of transport in chemical variability, evaluate model physics, and interpret field campaign observations. We show that the specified dynamics scheme in CESM2 erroneously suppresses convection and induces circulation errors that project onto errors in tracers, even using the most optimal settings. Development of a more sophisticated scheme is necessary for future progress.
Anton Laakso, Ulrike Niemeier, Daniele Visioni, Simone Tilmes, and Harri Kokkola
Atmos. Chem. Phys., 22, 93–118,Short summary
The use of different spatio-temporal sulfur injection strategies with different magnitudes to create an artificial reflective aerosol layer to cool the climate is studied using sectional and modal aerosol schemes in a climate model. There are significant differences in the results depending on the aerosol microphysical module used. Different spatio-temporal injection strategies have a significant impact on the magnitude and zonal distribution of radiative forcing and atmospheric dynamics.
Jin Liao, Glenn M. Wolfe, Reem A. Hannun, Jason M. St. Clair, Thomas F. Hanisco, Jessica B. Gilman, Aaron Lamplugh, Vanessa Selimovic, Glenn S. Diskin, John B. Nowak, Hannah S. Halliday, Joshua P. DiGangi, Samuel R. Hall, Kirk Ullmann, Christopher D. Holmes, Charles H. Fite, Anxhelo Agastra, Thomas B. Ryerson, Jeff Peischl, Ilann Bourgeois, Carsten Warneke, Matthew M. Coggon, Georgios I. Gkatzelis, Kanako Sekimoto, Alan Fried, Dirk Richter, Petter Weibring, Eric C. Apel, Rebecca S. Hornbrook, Steven S. Brown, Caroline C. Womack, Michael A. Robinson, Rebecca A. Washenfelder, Patrick R. Veres, and J. Andrew Neuman
Atmos. Chem. Phys., 21, 18319–18331,Short summary
Formaldehyde (HCHO) is an important oxidant precursor and affects the formation of O3 and other secondary pollutants in wildfire plumes. We disentangle the processes controlling HCHO evolution from wildfire plumes sampled by NASA DC-8 during FIREX-AQ. We find that OH abundance rather than normalized OH reactivity is the main driver of fire-to-fire variability in HCHO secondary production and estimate an effective HCHO yield per volatile organic compound molecule oxidized in wildfire plumes.
Keith B. Rodgers, Sun-Seon Lee, Nan Rosenbloom, Axel Timmermann, Gokhan Danabasoglu, Clara Deser, Jim Edwards, Ji-Eun Kim, Isla R. Simpson, Karl Stein, Malte F. Stuecker, Ryohei Yamaguchi, Tamás Bódai, Eui-Seok Chung, Lei Huang, Who M. Kim, Jean-François Lamarque, Danica L. Lombardozzi, William R. Wieder, and Stephen G. Yeager
Earth Syst. Dynam., 12, 1393–1411,Short summary
A large ensemble of simulations with 100 members has been conducted with the state-of-the-art CESM2 Earth system model, using historical and SSP3-7.0 forcing. Our main finding is that there are significant changes in the variance of the Earth system in response to anthropogenic forcing, with these changes spanning a broad range of variables important to impacts for human populations and ecosystems.
Joël Thanwerdas, Marielle Saunois, Isabelle Pison, Didier Hauglustaine, Antoine Berchet, Bianca Baier, Colm Sweeney, and Philippe Bousquet
Atmos. Chem. Phys. Discuss.,
Preprint under review for ACPShort summary
Atmospheric methane (CH4) concentrations have been rising since 2007, resulting from an imbalance between CH4 sources and sinks. The CH4 budget is generally estimated through top-down approaches using CH4 and δ13C(CH4) observations as constraints. The oxidation by chlorine (Cl) contributes little to the total oxidation of CH4 but strongly influences δ13C(CH4). Here, we compare multiple recent Cl fields and quantify the influence of Cl concentrations on CH4, δ13C(CH4) and CH4 budget estimates.
Cyril Caram, Sophie Szopa, Anne Cozic, Slimane Bekki, Carlos Cuevas, and Alfonso Saiz-Lopez
Geosci. Model Dev. Discuss.,
Revised manuscript under review for GMDShort summary
We studied the role of halogenated compounds (containing chlorine, bromine and iodine), emitted by natural processes (mainly above the oceans) on the chemistry of the lower layers of the atmosphere. We introduced this relatively new chemistry in a 3D climate-chemistry model, and looked at how this chemistry will disrupt the ozone. We showed that the concentration of ozone decreases by 22 % worldwide and that of the atmospheric detergent, OH, by 8 %.
Eric A. Ray, Elliot L. Atlas, Sue Schauffler, Sofia Chelpon, Laura Pan, Harald Bönisch, and Karen H. Rosenlof
Atmos. Chem. Phys. Discuss.,
Revised manuscript accepted for ACPShort summary
The movement of air masses and the trace gases they contain from the Earth’s surface into the upper troposphere and lower stratosphere (UTLS) can have important implications for the radiative and chemical balance of the atmosphere. In this study we build on recent techniques and use new ones to estimate a range of transport diagnostics based on simultaneously measured trace gases in the UTLS during the monsoon season in North America.
Paul D. Hamer, Virginie Marécal, Ryan Hossaini, Michel Pirre, Gisèle Krysztofiak, Franziska Ziska, Andreas Engel, Stephan Sala, Timo Keber, Harald Bönisch, Elliot Atlas, Kirstin Krüger, Martyn Chipperfield, Valery Catoire, Azizan A. Samah, Marcel Dorf, Phang Siew Moi, Hans Schlager, and Klaus Pfeilsticker
Atmos. Chem. Phys., 21, 16955–16984,Short summary
Bromoform is a stratospheric ozone-depleting gas released by seaweed and plankton transported to the stratosphere via convection in the tropics. We study the chemical interactions of bromoform and its derivatives within convective clouds using a cloud-scale model and observations. Our findings are that soluble bromine gases are efficiently washed out and removed within the convective clouds and that most bromine is transported vertically to the upper troposphere in the form of bromoform.
Christian Rödenbeck, Tim DeVries, Judith Hauck, Corinne Le Quéré, and Ralph Keeling
Revised manuscript accepted for BGShort summary
The ocean is an important part of the global carbon cycle, taking up about a quarter of the anthropgenic CO2 emitted by burning of fossil fuels, and thus slowing down climate change. However, the CO2 uptake by the ocean is, in turn, affected by variability and trends in climate. Here we use carbon measurements in the surface ocean to quantify the response of the oceanic CO2 exchange to environmental conditions, and discuss possible mechanisms underlying this response.
Yuqiang Zhang, Drew Shindell, Karl Seltzer, Lu Shen, Jean-Francois Lamarque, Qiang Zhang, Bo Zheng, Jia Xing, Zhe Jiang, and Lei Zhang
Atmos. Chem. Phys., 21, 16051–16065,Short summary
In this study, we use a global chemical transport model to simulate the effects on global air quality and human health due to emission changes in China from 2010 to 2017. By performing sensitivity analysis, we found that the air pollution control policies not only decrease the air pollutant concentration but also bring significant co-benefits in air quality to downwind regions. The benefits for the improved air pollution are dominated by PM2.5.
Arseniy Karagodin-Doyennel, Eugene Rozanov, Timofei Sukhodolov, Tatiana Egorova, Alfonso Saiz-Lopez, Carlos A. Cuevas, Rafael P. Fernandez, Tomás Sherwen, Rainer Volkamer, Theodore K. Koenig, Tanguy Giroud, and Thomas Peter
Geosci. Model Dev., 14, 6623–6645,Short summary
Here, we present the iodine chemistry module in the SOCOL-AERv2 model. The obtained iodine distribution demonstrated a good agreement when validated against other simulations and available observations. We also estimated the iodine influence on ozone in the case of present-day iodine emissions, the sensitivity of ozone to doubled iodine emissions, and when considering only organic or inorganic iodine sources. The new model can be used as a tool for further studies of iodine effects on ozone.
Catherine Wilka, Susan Solomon, Doug Kinnison, and David Tarasick
Atmos. Chem. Phys., 21, 15771–15781,Short summary
We use satellite and balloon measurements to evaluate modeled ozone loss seen in the unusually cold Arctic of 2020 in the real world and compare it to simulations of a world avoided. We show that extensive denitrification in 2020 provides an important test case for stratospheric model process representations. If the Montreal Protocol had not banned ozone-depleting substances, an Arctic ozone hole would have emerged for the first time in spring 2020 that is comparable to those in the Antarctic.
Eric J. Hintsa, Fred L. Moore, Dale F. Hurst, Geoff S. Dutton, Bradley D. Hall, J. David Nance, Ben R. Miller, Stephen A. Montzka, Laura P. Wolton, Audra McClure-Begley, James W. Elkins, Emrys G. Hall, Allen F. Jordan, Andrew W. Rollins, Troy D. Thornberry, Laurel A. Watts, Chelsea R. Thompson, Jeff Peischl, Ilann Bourgeois, Thomas B. Ryerson, Bruce C. Daube, Yenny Gonzalez Ramos, Roisin Commane, Gregory W. Santoni, Jasna V. Pittman, Steven C. Wofsy, Eric Kort, Glenn S. Diskin, and T. Paul Bui
Atmos. Meas. Tech., 14, 6795–6819,Short summary
We built UCATS to study atmospheric chemistry and transport. It has measured trace gases including CFCs, N2O, SF6, CH4, CO, and H2 with gas chromatography, as well as ozone and water vapor. UCATS has been part of missions to study the tropical tropopause; transport of air into the stratosphere; greenhouse gases, transport, and chemistry in the troposphere; and ozone chemistry, on both piloted and unmanned aircraft. Its design, capabilities, and some results are shown and described here.
Bharat Rastogi, John B. Miller, Micheal Trudeau, Arlyn E. Andrews, Lei Hu, Marikate Mountain, Thomas Nehrkorn, Bianca Baier, Kathryn McKain, John Mund, Kaiyu Guan, and Caroline B. Alden
Atmos. Chem. Phys., 21, 14385–14401,Short summary
Predicting Earth's climate is difficult, partly due to uncertainty in forecasting how much CO2 can be removed by oceans and plants, because we cannot measure these exchanges directly on large scales. Satellites such as NASA's OCO-2 can provide part of the needed information, but data need to be highly precise and accurate. We evaluate these data and find small biases in certain months that are similar to the signals of interest. We argue that continued improvement of these data is necessary.
Nobuyuki Aoki, Shigeyuki Ishidoya, Yasunori Tohjima, Shinji Morimoto, Ralph F. Keeling, Adam Cox, Shuichiro Takebayashi, and Shohei Murayama
Atmos. Meas. Tech., 14, 6181–6193,Short summary
Observing the minimal long-term change in atmospheric O2 molar fraction combined with CO2 observation enables us to estimate terrestrial biospheric and oceanic CO2 uptakes separately. In this study, we firstly identified the span offset between the laboratory O2 scales using our developed high-precision standard mixtures, suggesting that the result may allow us to estimate terrestrial biospheric and oceanic CO2 uptakes precisely.
Tao Tang, Drew Shindell, Yuqiang Zhang, Apostolos Voulgarakis, Jean-Francois Lamarque, Gunnar Myhre, Gregory Faluvegi, Bjørn H. Samset, Timothy Andrews, Dirk Olivié, Toshihiko Takemura, and Xuhui Lee
Atmos. Chem. Phys., 21, 13797–13809,Short summary
Previous studies showed that black carbon (BC) could warm the surface with decreased incoming radiation. With climate models, we found that the surface energy redistribution plays a more crucial role in surface temperature compared with other forcing agents. Though BC could reduce the surface heating, the energy dissipates less efficiently, which is manifested by reduced convective and evaporative cooling, thereby warming the surface.
Hao Guo, Clare M. Flynn, Michael J. Prather, Sarah A. Strode, Stephen D. Steenrod, Louisa Emmons, Forrest Lacey, Jean-Francois Lamarque, Arlene M. Fiore, Gus Correa, Lee T. Murray, Glenn M. Wolfe, Jason M. St. Clair, Michelle Kim, John Crounse, Glenn Diskin, Joshua DiGangi, Bruce C. Daube, Roisin Commane, Kathryn McKain, Jeff Peischl, Thomas B. Ryerson, Chelsea Thompson, Thomas F. Hanisco, Donald Blake, Nicola J. Blake, Eric C. Apel, Rebecca S. Hornbrook, James W. Elkins, Eric J. Hintsa, Fred L. Moore, and Steven Wofsy
Atmos. Chem. Phys., 21, 13729–13746,Short summary
The NASA Atmospheric Tomography (ATom) mission built a climatology of the chemical composition of tropospheric air parcels throughout the middle of the Pacific and Atlantic oceans. The level of detail allows us to reconstruct the photochemical budgets of O3 and CH4 over these vast, remote regions. We find that most of the chemical heterogeneity is captured at the resolution used in current global chemistry models and that the majority of reactivity occurs in the
hottest20 % of parcels.
Thierno Doumbia, Claire Granier, Nellie Elguindi, Idir Bouarar, Sabine Darras, Guy Brasseur, Benjamin Gaubert, Yiming Liu, Xiaoqin Shi, Trissevgeni Stavrakou, Simone Tilmes, Forrest Lacey, Adrien Deroubaix, and Tao Wang
Earth Syst. Sci. Data, 13, 4191–4206,Short summary
Most countries around the world have implemented control measures to combat the spread of the COVID-19 pandemic, resulting in significant changes in economic and personal activities. We developed the CONFORM (COvid-19 adjustmeNt Factors fOR eMissions) dataset to account for changes in emissions during lockdowns. This dataset was created with the intention of being directly applicable to existing global and regional inventories used in chemical transport models.
Anoop S. Mahajan, Mriganka S. Biswas, Steffen Beirle, Thomas Wagner, Anja Schönhardt, Nuria Benavent, and Alfonso Saiz-Lopez
Atmos. Chem. Phys., 21, 11829–11842,Short summary
Iodine plays a vital role in oxidation chemistry over Antarctica, with past observations showing highly elevated levels of iodine oxide (IO) leading to severe depletion of boundary layer ozone. We present IO observations over three summers (2015–2017) at the Indian Antarctic bases of Bharati and Maitri. IO was observed during all campaigns with mixing ratios below 2 pptv, which is lower than the peak levels observed in West Antarctica, showing the differences in regional chemistry and emissions.
Yenny Gonzalez, Róisín Commane, Ethan Manninen, Bruce C. Daube, Luke D. Schiferl, J. Barry McManus, Kathryn McKain, Eric J. Hintsa, James W. Elkins, Stephen A. Montzka, Colm Sweeney, Fred Moore, Jose L. Jimenez, Pedro Campuzano Jost, Thomas B. Ryerson, Ilann Bourgeois, Jeff Peischl, Chelsea R. Thompson, Eric Ray, Paul O. Wennberg, John Crounse, Michelle Kim, Hannah M. Allen, Paul A. Newman, Britton B. Stephens, Eric C. Apel, Rebecca S. Hornbrook, Benjamin A. Nault, Eric Morgan, and Steven C. Wofsy
Atmos. Chem. Phys., 21, 11113–11132,Short summary
Vertical profiles of N2O and a variety of chemical species and aerosols were collected nearly from pole to pole over the oceans during the NASA Atmospheric Tomography mission. We observed that tropospheric N2O variability is strongly driven by the influence of stratospheric air depleted in N2O, especially at middle and high latitudes. We also traced the origins of biomass burning and industrial emissions and investigated their impact on the variability of tropospheric N2O.
Daniele Visioni, Douglas G. MacMartin, Ben Kravitz, Olivier Boucher, Andy Jones, Thibaut Lurton, Michou Martine, Michael J. Mills, Pierre Nabat, Ulrike Niemeier, Roland Séférian, and Simone Tilmes
Atmos. Chem. Phys., 21, 10039–10063,Short summary
A new set of simulations is used to investigate commonalities, differences and sources of uncertainty when simulating the injection of SO2 in the stratosphere in order to mitigate the effects of climate change (solar geoengineering). The models differ in how they simulate the aerosols and how they spread around the stratosphere, resulting in differences in projected regional impacts. Overall, however, the models agree that aerosols have the potential to mitigate the warming produced by GHGs.
Dien Wu, John C. Lin, Henrique F. Duarte, Vineet Yadav, Nicholas C. Parazoo, Tomohiro Oda, and Eric A. Kort
Geosci. Model Dev., 14, 3633–3661,Short summary
A model (SMUrF) is presented that estimates biogenic CO2 fluxes over cities around the globe to separate out biogenic fluxes from anthropogenic emissions. The model leverages satellite-based solar-induced fluorescence data and a machine-learning technique. We evaluate the biogenic fluxes against flux observations and show contrasts between biogenic and anthropogenic fluxes over cities, revealing urban–rural flux gradients, diurnal cycles, and the resulting imprints on atmospheric-column CO2.
Elizabeth B. Wiggins, Arlyn Andrews, Colm Sweeney, John B. Miller, Charles E. Miller, Sander Veraverbeke, Roisin Commane, Steven Wofsy, John M. Henderson, and James T. Randerson
Atmos. Chem. Phys., 21, 8557–8574,Short summary
We analyzed high-resolution trace gas measurements collected from a tower in Alaska during a very active fire season to improve our understanding of trace gas emissions from boreal forest fires. Our results suggest previous studies may have underestimated emissions from smoldering combustion in boreal forest fires.
Anoop S. Mahajan, Qinyi Li, Swaleha Inamdar, Kirpa Ram, Alba Badia, and Alfonso Saiz-Lopez
Atmos. Chem. Phys., 21, 8437–8454,Short summary
Using a regional model, we show that iodine-catalysed reactions cause large regional changes in the chemical composition in the northern Indian Ocean, with peak changes of up to 25 % in O3, 50 % in nitrogen oxides (NO and NO2), 15 % in hydroxyl radicals (OH), 25 % in hydroperoxyl radicals (HO2), and up to a 50 % change in the nitrate radical (NO3). These results show the importance of including iodine chemistry in modelling the atmosphere in this region.
Genevieve Jay Brett, Daniel B. Whitt, Matthew C. Long, Frank Bryan, Kate Feloy, and Kelvin J. Richards
Biogeosciences, 18, 3123–3145,Short summary
We quantify one form of uncertainty in modeled 21st-century changes in phytoplankton growth. The supply of nutrients from deep to surface waters decreases in the warmer future ocean, but the effect on phytoplankton growth also depends on changes in available light, how much light and nutrient the plankton need, and how fast they can grow. These phytoplankton properties can be summarized as a biological timescale: when it is short, future growth decreases twice as much as when it is long.
David R. Lyon, Benjamin Hmiel, Ritesh Gautam, Mark Omara, Katherine A. Roberts, Zachary R. Barkley, Kenneth J. Davis, Natasha L. Miles, Vanessa C. Monteiro, Scott J. Richardson, Stephen Conley, Mackenzie L. Smith, Daniel J. Jacob, Lu Shen, Daniel J. Varon, Aijun Deng, Xander Rudelis, Nikhil Sharma, Kyle T. Story, Adam R. Brandt, Mary Kang, Eric A. Kort, Anthony J. Marchese, and Steven P. Hamburg
Atmos. Chem. Phys., 21, 6605–6626,Short summary
The Permian Basin (USA) is the world’s largest oil field. We use tower- and aircraft-based approaches to measure how methane emissions in the Permian Basin changed throughout 2020. In early 2020, 3.3 % of the region’s gas was emitted; then in spring 2020, the loss rate temporarily dropped to 1.9 % as oil price crashed. We find this short-term reduction to be a result of reduced well development, less gas flaring, and fewer abnormal events despite minimal reductions in oil and gas production.
Sébastien Roche, Kimberly Strong, Debra Wunch, Joseph Mendonca, Colm Sweeney, Bianca Baier, Sébastien C. Biraud, Joshua L. Laughner, Geoffrey C. Toon, and Brian J. Connor
Atmos. Meas. Tech., 14, 3087–3118,Short summary
We evaluate CO2 profile retrievals from ground-based near-infrared solar absorption spectra after implementing several improvements to the GFIT2 retrieval algorithm. Realistic errors in the a priori temperature profile (~ 2 °C in the lower troposphere) are found to be the leading source of differences between the retrieved and true CO2 profiles, differences that are larger than typical CO2 variability. A temperature retrieval or correction is critical to improve CO2 profile retrieval results.
Fernando Chouza, Thierry Leblanc, Mark Brewer, Patrick Wang, Sabino Piazzolla, Gabriele Pfister, Rajesh Kumar, Carl Drews, Simone Tilmes, Louisa Emmons, and Matthew Johnson
Atmos. Chem. Phys., 21, 6129–6153,Short summary
The tropospheric ozone lidar at the JPL Table Mountain Facility (TMF) was used to investigate the impact of Los Angeles (LA) Basin pollution transport and stratospheric intrusions in the planetary boundary layer on the San Gabriel Mountains. The results of this study indicate a dominant role of the LA Basin pollution on days when high ozone levels were observed at TMF (March–October period).
David Garcia-Nieto, Nuria Benavent, Rafael Borge, and Alfonso Saiz-Lopez
Atmos. Meas. Tech., 14, 2941–2955,Short summary
Trace gases play a key role in the chemistry of urban atmospheres. Therefore, knowledge about their spatial distribution is needed to fully characterize the air quality in urban areas. Using a new Multi-AXis Differential Optical Absorption Spectroscopy two-dimensional (MAXDOAS-2D) instrument, along with inversion algorithms, we report for the first time two-dimensional maps of NO2 concentrations in the city of Madrid, Spain.
Britton B. Stephens, Eric J. Morgan, Jonathan D. Bent, Ralph F. Keeling, Andrew S. Watt, Stephen R. Shertz, and Bruce C. Daube
Atmos. Meas. Tech., 14, 2543–2574,Short summary
We describe methods used to make high-precision global-scale airborne measurements of atmospheric oxygen concentrations over a period of 20 years in order to study the global carbon cycle. Our techniques include an in situ vacuum ultraviolet absorption instrument and a pressure- and flow-controlled, cryogenically dried, glass flask sampler. We have deployed these instruments in 15 airborne research campaigns spanning from the Earth’s surface to the lower stratosphere and from pole to pole.
Benjamin Birner, William Paplawsky, Jeffrey Severinghaus, and Ralph F. Keeling
Atmos. Meas. Tech., 14, 2515–2527,Short summary
The atmospheric helium-to-nitrogen ratio is a promising indicator for circulation changes in the upper atmosphere and fossil fuel burning by humans. We present a very precise analysis method to determine changes in the helium-to-nitrogen ratio of air samples. The method relies on stabilizing the gas flow to a mass spectrometer and continuous removal of reactive gases. These advances enable new insights and monitoring possibilities for anthropogenic and natural processes.
Ben Kravitz, Douglas G. MacMartin, Daniele Visioni, Olivier Boucher, Jason N. S. Cole, Jim Haywood, Andy Jones, Thibaut Lurton, Pierre Nabat, Ulrike Niemeier, Alan Robock, Roland Séférian, and Simone Tilmes
Atmos. Chem. Phys., 21, 4231–4247,Short summary
This study investigates multi-model response to idealized geoengineering (high CO2 with solar reduction) across two different generations of climate models. We find that, with the exception of a few cases, the results are unchanged between the different generations. This gives us confidence that broad conclusions about the response to idealized geoengineering are robust.
Paul T. Griffiths, Lee T. Murray, Guang Zeng, Youngsub Matthew Shin, N. Luke Abraham, Alexander T. Archibald, Makoto Deushi, Louisa K. Emmons, Ian E. Galbally, Birgit Hassler, Larry W. Horowitz, James Keeble, Jane Liu, Omid Moeini, Vaishali Naik, Fiona M. O'Connor, Naga Oshima, David Tarasick, Simone Tilmes, Steven T. Turnock, Oliver Wild, Paul J. Young, and Prodromos Zanis
Atmos. Chem. Phys., 21, 4187–4218,Short 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.
Chaim I. Garfinkel, Ohad Harari, Shlomi Ziskin Ziv, Jian Rao, Olaf Morgenstern, Guang Zeng, Simone Tilmes, Douglas Kinnison, Fiona M. O'Connor, Neal Butchart, Makoto Deushi, Patrick Jöckel, Andrea Pozzer, and Sean Davis
Atmos. Chem. Phys., 21, 3725–3740,Short summary
Water vapor is the dominant greenhouse gas in the atmosphere, and El Niño is the dominant mode of variability in the ocean–atmosphere system. The connection between El Niño and water vapor above ~ 17 km is unclear, with single-model studies reaching a range of conclusions. This study examines this connection in 12 different models. While there are substantial differences among the models, all models appear to capture the fundamental physical processes correctly.
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., 21, 3593–3605,Short summary
The aims here are to assess the role of aerosols in 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.
Jin Ma, Linda M. J. Kooijmans, Ara Cho, Stephen A. Montzka, Norbert Glatthor, John R. Worden, Le Kuai, Elliot L. Atlas, and Maarten C. Krol
Atmos. Chem. Phys., 21, 3507–3529,Short summary
Carbonyl sulfide is an important trace gas in the atmosphere and useful to estimating gross primary productivity in ecosystems, but its sources and sinks remain highly uncertain. Therefore, we applied inverse model system TM5-4DVAR to better constrain the global budget. Our finding is in line with earlier studies, pointing to missing sources in the tropics and more uptake in high latitudes. We also stress the necessity of more ground-based observations and satellite data assimilation in future.
Duseong S. Jo, Alma Hodzic, Louisa K. Emmons, Simone Tilmes, Rebecca H. Schwantes, Michael J. Mills, Pedro Campuzano-Jost, Weiwei Hu, Rahul A. Zaveri, Richard C. Easter, Balwinder Singh, Zheng Lu, Christiane Schulz, Johannes Schneider, John E. Shilling, Armin Wisthaler, and Jose L. Jimenez
Atmos. Chem. Phys., 21, 3395–3425,Short summary
Secondary organic aerosol (SOA) is a major component of submicron particulate matter, but there are a lot of uncertainties in the future prediction of SOA. We used CESM 2.1 to investigate future IEPOX SOA concentration changes. The explicit chemistry predicted substantial changes in IEPOX SOA depending on the future scenario, but the parameterization predicted weak changes due to simplified chemistry, which shows the importance of correct physicochemical dependencies in future SOA prediction.
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.
Patrick E. Sheese, Kaley A. Walker, Chris D. Boone, Doug A. Degenstein, Felicia Kolonjari, David Plummer, Douglas E. Kinnison, Patrick Jöckel, and Thomas von Clarmann
Atmos. Meas. Tech., 14, 1425–1438,Short summary
Output from climate chemistry models (CMAM, EMAC, and WACCM) is used to estimate the expected geophysical variability of ozone concentrations between coincident satellite instrument measurement times and geolocations. We use the Canadian ACE-FTS and OSIRIS instruments as a case study. Ensemble mean estimates are used to optimize coincidence criteria between the two instruments, allowing for the use of more coincident profiles while providing an estimate of the geophysical variation.
Sabine Robrecht, Bärbel Vogel, Simone Tilmes, and Rolf Müller
Atmos. Chem. Phys., 21, 2427–2455,Short summary
Column ozone protects life on Earth from radiation damage. Stratospheric chlorine compounds cause immense ozone loss in polar winter. Whether similar loss processes can occur in the lower stratosphere above North America today or in future is a matter of debate. We show that these ozone loss processes are very unlikely today or in future independently of whether sulfate geoengineering is applied and that less than 0.1 % of column ozone would be destroyed by this process in any future scenario.
Junjie Liu, Latha Baskaran, Kevin Bowman, David Schimel, A. Anthony Bloom, Nicholas C. Parazoo, Tomohiro Oda, Dustin Carroll, Dimitris Menemenlis, Joanna Joiner, Roisin Commane, Bruce Daube, Lucianna V. Gatti, Kathryn McKain, John Miller, Britton B. Stephens, Colm Sweeney, and Steven Wofsy
Earth Syst. Sci. Data, 13, 299–330,Short summary
On average, the terrestrial biosphere carbon sink is equivalent to ~ 20 % of fossil fuel emissions. Understanding where and why the terrestrial biosphere absorbs carbon from the atmosphere is pivotal to any mitigation policy. Here we present a regionally resolved satellite-constrained net biosphere exchange (NBE) dataset with corresponding uncertainties between 2010–2018: CMS-Flux NBE 2020. The dataset provides a unique perspective on monitoring regional contributions to the CO2 growth rate.
Shamil Maksyutov, Tomohiro Oda, Makoto Saito, Rajesh Janardanan, Dmitry Belikov, Johannes W. Kaiser, Ruslan Zhuravlev, Alexander Ganshin, Vinu K. Valsala, Arlyn Andrews, Lukasz Chmura, Edward Dlugokencky, László Haszpra, Ray L. Langenfelds, Toshinobu Machida, Takakiyo Nakazawa, Michel Ramonet, Colm Sweeney, and Douglas Worthy
Atmos. Chem. Phys., 21, 1245–1266,Short summary
In order to improve the top-down estimation of the anthropogenic greenhouse gas emissions, a high-resolution inverse modelling technique was developed for applications to global transport modelling of carbon dioxide and other greenhouse gases. A coupled Eulerian–Lagrangian transport model and its adjoint are combined with surface fluxes at 0.1° resolution to provide high-resolution forward simulation and inverse modelling of surface fluxes accounting for signals from emission hot spots.
Andy Jones, Jim M. Haywood, Anthony C. Jones, Simone Tilmes, Ben Kravitz, and Alan Robock
Atmos. Chem. Phys., 21, 1287–1304,Short summary
Two different methods of simulating a geoengineering scenario are compared using data from two different Earth system models. One method is very idealised while the other includes details of a plausible mechanism. The results from both models agree that the idealised approach does not capture an impact found when detailed modelling is included, namely that geoengineering induces a positive phase of the North Atlantic Oscillation which leads to warmer, wetter winters in northern Europe.
Marc von Hobe, Felix Ploeger, Paul Konopka, Corinna Kloss, Alexey Ulanowski, Vladimir Yushkov, Fabrizio Ravegnani, C. Michael Volk, Laura L. Pan, Shawn B. Honomichl, Simone Tilmes, Douglas E. Kinnison, Rolando R. Garcia, and Jonathon S. Wright
Atmos. Chem. Phys., 21, 1267–1285,Short summary
The Asian summer monsoon (ASM) is known to foster transport of polluted tropospheric air into the stratosphere. To test and amend our picture of ASM vertical transport, we analyse distributions of airborne trace gas observations up to 20 km altitude near the main ASM vertical conduit south of the Himalayas. We also show that a new high-resolution version of the global chemistry climate model WACCM is able to reproduce the observations well.
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.
Xueying Yu, Dylan B. Millet, Kelley C. Wells, Daven K. Henze, Hansen Cao, Timothy J. Griffis, Eric A. Kort, Genevieve Plant, Malte J. Deventer, Randall K. Kolka, D. Tyler Roman, Kenneth J. Davis, Ankur R. Desai, Bianca C. Baier, Kathryn McKain, Alan C. Czarnetzki, and A. Anthony Bloom
Atmos. Chem. Phys., 21, 951–971,Short summary
Methane concentrations have doubled since 1750. The US Upper Midwest is a key region contributing to such trends, but sources are poorly understood. We collected and analyzed aircraft data to resolve spatial and timing biases in wetland and livestock emission estimates and uncover errors in inventory treatment of manure management. We highlight the importance of intensive agriculture for the regional and US methane budgets and the potential for methane mitigation through improved management.
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.
Susan S. Kulawik, John R. Worden, Vivienne H. Payne, Dejian Fu, Steven C. Wofsy, Kathryn McKain, Colm Sweeney, Bruce C. Daube Jr., Alan Lipton, Igor Polonsky, Yuguang He, Karen E. Cady-Pereira, Edward J. Dlugokencky, Daniel J. Jacob, and Yi Yin
Atmos. Meas. Tech., 14, 335–354,Short summary
This paper shows comparisons of a new single-footprint methane product from the AIRS satellite to aircraft-based observations. We show that this AIRS methane product provides useful information to study seasonal and global methane trends of this important greenhouse gas.
Yuming Jin, Ralph F. Keeling, Eric J. Morgan, Eric Ray, Nicholas C. Parazoo, and Britton B. Stephens
Atmos. Chem. Phys., 21, 217–238,Short summary
We propose a new atmospheric coordinate (Mθe) based on equivalent potential temperature (θe) but with mass as the unit. This coordinate is useful in studying the spatial and temporal distribution of long-lived chemical tracers (CO2, CH4, O2 / N2, etc.) from sparse data, like airborne observation. Using this coordinate and sparse airborne observation (HIPPO and ATom), we resolve the Northern Hemisphere mass-weighted average CO2 seasonal cycle with high accuracy.
Arseniy Karagodin-Doyennel, Eugene Rozanov, Ales Kuchar, William Ball, Pavle Arsenovic, Ellis Remsberg, Patrick Jöckel, Markus Kunze, David A. Plummer, Andrea Stenke, Daniel Marsh, Doug Kinnison, and Thomas Peter
Atmos. Chem. Phys., 21, 201–216,Short summary
The solar signal in the mesospheric H2O and CO was extracted from the CCMI-1 model simulations and satellite observations using multiple linear regression (MLR) analysis. MLR analysis shows a pronounced and statistically robust solar signal in both H2O and CO. The model results show a general agreement with observations reproducing a negative/positive solar signal in H2O/CO. The pattern of the solar signal varies among the considered models, reflecting some differences in the model setup.
Agnieszka Kupc, Christina J. Williamson, Anna L. Hodshire, Jan Kazil, Eric Ray, T. Paul Bui, Maximilian Dollner, Karl D. Froyd, Kathryn McKain, Andrew Rollins, Gregory P. Schill, Alexander Thames, Bernadett B. Weinzierl, Jeffrey R. Pierce, and Charles A. Brock
Atmos. Chem. Phys., 20, 15037–15060,Short summary
Tropical upper troposphere over the Atlantic and Pacific oceans is a major source region of new particles. These particles are associated with the outflow from deep convection. We investigate the processes that govern the formation of these particles and their initial growth and show that none of the formation schemes commonly used in global models are consistent with observations. Using newer schemes indicates that organic compounds are likely important as nucleating and initial growth agents.
Benjamin Gaubert, Louisa K. Emmons, Kevin Raeder, Simone Tilmes, Kazuyuki Miyazaki, Avelino F. Arellano Jr., Nellie Elguindi, Claire Granier, Wenfu Tang, Jérôme Barré, Helen M. Worden, Rebecca R. Buchholz, David P. Edwards, Philipp Franke, Jeffrey L. Anderson, Marielle Saunois, Jason Schroeder, Jung-Hun Woo, Isobel J. Simpson, Donald R. Blake, Simone Meinardi, Paul O. Wennberg, John Crounse, Alex Teng, Michelle Kim, Russell R. Dickerson, Hao He, Xinrong Ren, Sally E. Pusede, and Glenn S. Diskin
Atmos. Chem. Phys., 20, 14617–14647,Short summary
This study investigates carbon monoxide pollution in East Asia during spring using a numerical model, satellite remote sensing, and aircraft measurements. We found an underestimation of emission sources. Correcting the emission bias can improve air quality forecasting of carbon monoxide and other species including ozone. Results also suggest that controlling VOC and CO emissions, in addition to widespread NOx controls, can improve ozone pollution over East Asia.
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.
Petter Weibring, Dirk Richter, James G. Walega, Alan Fried, Joshua DiGangi, Hannah Halliday, Yonghoon Choi, Bianca Baier, Colm Sweeney, Ben Miller, Kenneth J. Davis, Zachary Barkley, and Michael D. Obland
Atmos. Meas. Tech., 13, 6095–6112,Short summary
The present study describes an autonomously operated instrument for high-precision (20–40 parts per trillion in 1 s) measurements of ethane during actual airborne operations on a small aircraft platform (NASA's King Air B200). This paper discusses the dynamic nature of airborne performance due to various aircraft-induced perturbations, methods devised to identify such events, and solutions we have enacted to circumvent these perturbations.
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.
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.
Yuanhong Zhao, Marielle Saunois, Philippe Bousquet, Xin Lin, Antoine Berchet, Michaela I. Hegglin, Josep G. Canadell, Robert B. Jackson, Makoto Deushi, Patrick Jöckel, Douglas Kinnison, Ole Kirner, Sarah Strode, Simone Tilmes, Edward J. Dlugokencky, and Bo Zheng
Atmos. Chem. Phys., 20, 13011–13022,Short summary
Decadal trends and variations in OH are critical for understanding atmospheric CH4 evolution. We quantify the impacts of OH trends and variations on the CH4 budget by conducting CH4 inversions on a decadal scale with an ensemble of OH fields. We find the negative OH anomalies due to enhanced fires can reduce the optimized CH4 emissions by up to 10 Tg yr−1 during El Niño years and the positive OH trend from 1986 to 2010 results in a ∼ 23 Tg yr−1 additional increase in optimized CH4 emissions.
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.
Daniele Minganti, Simon Chabrillat, Yves Christophe, Quentin Errera, Marta Abalos, Maxime Prignon, Douglas E. Kinnison, and Emmanuel Mahieu
Atmos. Chem. Phys., 20, 12609–12631,Short summary
The climatology of the N2O transport budget in the stratosphere is studied in the transformed Eulerian mean framework across a variety of datasets: a chemistry climate model, a chemistry transport model driven by four reanalyses and a chemical reanalysis. The impact of vertical advection on N2O agrees well in the datasets, but horizontal mixing presents large differences above the Antarctic and in the whole Northern Hemisphere.
Benjamin Birner, Martyn P. Chipperfield, Eric J. Morgan, Britton B. Stephens, Marianna Linz, Wuhu Feng, Chris Wilson, Jonathan D. Bent, Steven C. Wofsy, Jeffrey Severinghaus, and Ralph F. Keeling
Atmos. Chem. Phys., 20, 12391–12408,Short summary
With new high-precision observations from nine aircraft campaigns and 3-D chemical transport modeling, we show that the argon-to-nitrogen ratio (Ar / N2) in the lowermost stratosphere provides a useful constraint on the “age of air” (the time elapsed since entry of an air parcel into the stratosphere). Therefore, Ar / N2 in combination with traditional age-of-air indicators, such as CO2 and N2O, could provide new insights into atmospheric mixing and transport.
Lei Zhu, Gonzalo González Abad, Caroline R. Nowlan, Christopher Chan Miller, Kelly Chance, Eric C. Apel, Joshua P. DiGangi, Alan Fried, Thomas F. Hanisco, Rebecca S. Hornbrook, Lu Hu, Jennifer Kaiser, Frank N. Keutsch, Wade Permar, Jason M. St. Clair, and Glenn M. Wolfe
Atmos. Chem. Phys., 20, 12329–12345,Short summary
We develop a validation platform for satellite HCHO retrievals using in situ observations from 12 aircraft campaigns. The platform offers an alternative way to quickly assess systematic biases in HCHO satellite products over large domains and long periods, facilitating optimization of retrieval settings and the minimization of retrieval biases. Application to the NASA operational HCHO product indicates that relative biases range from −44.5 % to +112.1 % depending on locations and seasons.
Swaleha Inamdar, Liselotte Tinel, Rosie Chance, Lucy J. Carpenter, Prabhakaran Sabu, Racheal Chacko, Sarat C. Tripathy, Anvita U. Kerkar, Alok K. Sinha, Parli Venkateswaran Bhaskar, Amit Sarkar, Rajdeep Roy, Tomás Sherwen, Carlos Cuevas, Alfonso Saiz-Lopez, Kirpa Ram, and Anoop S. Mahajan
Atmos. Chem. Phys., 20, 12093–12114,Short summary
Iodine chemistry is generating a lot of interest because of its impacts on the oxidising capacity of the marine boundary and depletion of ozone. However, one of the challenges has been predicting the right levels of iodine in the models, which depend on parameterisations for emissions from the sea surface. This paper discusses the different parameterisations available and compares them with observations, showing that our current knowledge is still insufficient, especially on a regional scale.
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.
Yang Wang, Arnoud Apituley, Alkiviadis Bais, Steffen Beirle, Nuria Benavent, Alexander Borovski, Ilya Bruchkouski, Ka Lok Chan, Sebastian Donner, Theano Drosoglou, Henning Finkenzeller, Martina M. Friedrich, Udo Frieß, David Garcia-Nieto, Laura Gómez-Martín, François Hendrick, Andreas Hilboll, Junli Jin, Paul Johnston, Theodore K. Koenig, Karin Kreher, Vinod Kumar, Aleksandra Kyuberis, Johannes Lampel, Cheng Liu, Haoran Liu, Jianzhong Ma, Oleg L. Polyansky, Oleg Postylyakov, Richard Querel, Alfonso Saiz-Lopez, Stefan Schmitt, Xin Tian, Jan-Lukas Tirpitz, Michel Van Roozendael, Rainer Volkamer, Zhuoru Wang, Pinhua Xie, Chengzhi Xing, Jin Xu, Margarita Yela, Chengxin Zhang, and Thomas Wagner
Atmos. Meas. Tech., 13, 5087–5116,
Thomas R. Lewis, Juan Carlos Gómez Martín, Mark A. Blitz, Carlos A. Cuevas, John M. C. Plane, and Alfonso Saiz-Lopez
Atmos. Chem. Phys., 20, 10865–10887,Short summary
Iodine-bearing gasses emitted from the sea surface are chemically processed in the atmosphere, leading to iodine accumulation in aerosol and transport to continental ecosystems. Such processing involves light-induced break-up of large, particle-forming iodine oxides into smaller, ozone-depleting molecules. We combine experiments and theory to report the photolysis efficiency of iodine oxides required to assess the impact of iodine on ozone depletion and particle formation.
Sara Martínez-Alonso, Merritt Deeter, Helen Worden, Tobias Borsdorff, Ilse Aben, Róisin Commane, Bruce Daube, Gene Francis, Maya George, Jochen Landgraf, Debbie Mao, Kathryn McKain, and Steven Wofsy
Atmos. Meas. Tech., 13, 4841–4864,Short summary
CO is of great importance in climate and air quality studies. To understand newly available TROPOMI data in the frame of the global CO record, we compared those to satellite (MOPITT) and airborne (ATom) CO datasets. The MOPITT dataset is the longest to date (2000–present) and is well-characterized. We used ATom to validate cloudy TROPOMI data over oceans and investigate TROPOMI's vertical sensitivity to CO. Our results show that TROPOMI CO data are in excellent agreement with the other datasets.
Ilann Bourgeois, Jeff Peischl, Chelsea R. Thompson, Kenneth C. Aikin, Teresa Campos, Hannah Clark, Róisín Commane, Bruce Daube, Glenn W. Diskin, James W. Elkins, Ru-Shan Gao, Audrey Gaudel, Eric J. Hintsa, Bryan J. Johnson, Rigel Kivi, Kathryn McKain, Fred L. Moore, David D. Parrish, Richard Querel, Eric Ray, Ricardo Sánchez, Colm Sweeney, David W. Tarasick, Anne M. Thompson, Valérie Thouret, Jacquelyn C. Witte, Steve C. Wofsy, and Thomas B. Ryerson
Atmos. Chem. Phys., 20, 10611–10635,
Colm Sweeney, Abhishek Chatterjee, Sonja Wolter, Kathryn McKain, Robert Bogue, Tim Newberger, Lei Hu, Lesley Ott, Benjamin Poulter, Luke Schiferl, Brad Weir, Zhen Zhang, and Charles E. Miller
Atmos. Chem. Phys. Discuss.,
Revised manuscript accepted for ACPShort summary
The Arctic Carbon Atmospheric Profiles (Arctic-CAP) project demonstrates the utility of aircraft profiles for independent evaluation of model derived emissions/uptake of atmospheric CO2, CH4 and CO from land and ocean. Comparison with the Goddard Earth Observing System (GEOS) modeling system suggests that fluxes of CO2 are very consistent with observations while CH4 have some regional and seasonal biases and that CO comparison is complicated by transport errors.
Wenfu Tang, Benjamin Gaubert, Louisa Emmons, Yonghoon Choi, Joshua P. DiGangi, Glenn S. Diskin, Xiaomei Xu, Cenlin He, Helen Worden, Simone Tilmes, Rebecca Buchholz, Hannah S. Halliday, and Avelino F. Arellano
Atmos. Chem. Phys. Discuss.,
Revised manuscript not acceptedShort summary
A specific demonstration of the potential use of correlative information from carbon monoxide to refine estimates of regional carbon dioxide emissions from fossil fuel combustion.
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.
Hiroyuki Tsujino, L. Shogo Urakawa, Stephen M. Griffies, Gokhan Danabasoglu, Alistair J. Adcroft, Arthur E. Amaral, Thomas Arsouze, Mats Bentsen, Raffaele Bernardello, Claus W. Böning, Alexandra Bozec, Eric P. Chassignet, Sergey Danilov, Raphael Dussin, Eleftheria Exarchou, Pier Giuseppe Fogli, Baylor Fox-Kemper, Chuncheng Guo, Mehmet Ilicak, Doroteaciro Iovino, Who M. Kim, Nikolay Koldunov, Vladimir Lapin, Yiwen Li, Pengfei Lin, Keith Lindsay, Hailong Liu, Matthew C. Long, Yoshiki Komuro, Simon J. Marsland, Simona Masina, Aleksi Nummelin, Jan Klaus Rieck, Yohan Ruprich-Robert, Markus Scheinert, Valentina Sicardi, Dmitry Sidorenko, Tatsuo Suzuki, Hiroaki Tatebe, Qiang Wang, Stephen G. Yeager, and Zipeng Yu
Geosci. Model Dev., 13, 3643–3708,Short summary
The OMIP-2 framework for global ocean–sea-ice model simulations is assessed by comparing multi-model means from 11 CMIP6-class global ocean–sea-ice models calculated separately for the OMIP-1 and OMIP-2 simulations. Many features are very similar between OMIP-1 and OMIP-2 simulations, and yet key improvements in transitioning from OMIP-1 to OMIP-2 are also identified. Thus, the present assessment justifies that future ocean–sea-ice model development and analysis studies use the OMIP-2 framework.
Johannes C. Laube, Emma C. Leedham Elvidge, Karina E. Adcock, Bianca Baier, Carl A. M. Brenninkmeijer, Huilin Chen, Elise S. Droste, Jens-Uwe Grooß, Pauli Heikkinen, Andrew J. Hind, Rigel Kivi, Alexander Lojko, Stephen A. Montzka, David E. Oram, Steve Randall, Thomas Röckmann, William T. Sturges, Colm Sweeney, Max Thomas, Elinor Tuffnell, and Felix Ploeger
Atmos. Chem. Phys., 20, 9771–9782,Short summary
We demonstrate that AirCore technology, which is based on small low-cost balloons, can provide access to trace gas measurements such as CFCs at ultra-low abundances. This is a new way to quantify ozone-depleting, and related, substances in the stratosphere, which is largely inaccessible to aircraft. We show two potential uses: (a) tracking the stratospheric circulation, which is predicted to change, and (b) assessing three common meteorological reanalyses driving a global stratospheric model.
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,
Yangyang Xu, Lei Lin, Simone Tilmes, Katherine Dagon, Lili Xia, Chenrui Diao, Wei Cheng, Zhili Wang, Isla Simpson, and Lorna Burnell
Earth Syst. Dynam., 11, 673–695,Short summary
Two geoengineering schemes to mitigate global warming, (a) capturing atmospheric CO2 and (b) injecting stratospheric sulfur gas, are compared. Based on two sets of large-ensemble model experiments, we show that sulfur injection will effectively mitigate projected terrestrial drying over the Americas, and the mitigation benefit will emerge more quickly than with carbon capture. Innovative means of sulfur injection should continue to be explored as one potential low-cost climate solution.
Ulrike Niemeier, Jadwiga H. Richter, and Simone Tilmes
Atmos. Chem. Phys., 20, 8975–8987,Short summary
Artificial injections of SO2 into the tropical stratosphere show an impact on the quasi-biennial oscillation (QBO). Different numerical models show only qualitatively but not quantitatively consistent impacts. We show for two models that the response of the QBO is similar when a similar stratospheric heating rate is induced by SO2 injections of different amounts. The reason is very different vertical advection in the two models resulting in different aerosol burden and heating of the aerosols.
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.
Simone Tilmes, Douglas G. MacMartin, Jan T. M. Lenaerts, Leo van Kampenhout, Laura Muntjewerf, Lili Xia, Cheryl S. Harrison, Kristen M. Krumhardt, Michael J. Mills, Ben Kravitz, and Alan Robock
Earth Syst. Dynam., 11, 579–601,Short summary
This paper introduces new geoengineering model experiments as part of a larger model intercomparison effort, using reflective particles to block some of the incoming solar radiation to reach surface temperature targets. Outcomes of these applications are contrasted based on a high greenhouse gas emission pathway and a pathway with strong mitigation and negative emissions after 2040. We compare quantities that matter for societal and ecosystem impacts between the different scenarios.
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.
Katherine R. Travis, Colette L. Heald, Hannah M. Allen, Eric C. Apel, Stephen R. Arnold, Donald R. Blake, William H. Brune, Xin Chen, Róisín Commane, John D. Crounse, Bruce C. Daube, Glenn S. Diskin, James W. Elkins, Mathew J. Evans, Samuel R. Hall, Eric J. Hintsa, Rebecca S. Hornbrook, Prasad S. Kasibhatla, Michelle J. Kim, Gan Luo, Kathryn McKain, Dylan B. Millet, Fred L. Moore, Jeffrey Peischl, Thomas B. Ryerson, Tomás Sherwen, Alexander B. Thames, Kirk Ullmann, Xuan Wang, Paul O. Wennberg, Glenn M. Wolfe, and Fangqun Yu
Atmos. Chem. Phys., 20, 7753–7781,Short summary
Atmospheric models overestimate the rate of removal of trace gases by the hydroxyl radical (OH). This is a concern for studies of the climate and air quality impacts of human activities. Here, we evaluate the performance of a commonly used model of atmospheric chemistry against data from the NASA Atmospheric Tomography Mission (ATom) over the remote oceans where models have received little validation. The model is generally successful, suggesting that biases in OH may be a concern over land.
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.,
Preprint withdrawnShort 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.
Susann Tegtmeier, Elliot Atlas, Birgit Quack, Franziska Ziska, and Kirstin Krüger
Atmos. Chem. Phys., 20, 7103–7123,Short summary
We investigate emissions of brominated gases from the ocean and their contribution to stratospheric ozone depletion. Once in the atmosphere, these gases usually break down in less than 6 months. Their impact on the ozone layer depends on the prevailing atmospheric circulation, since transport to the stratosphere requires uplift. We combine aircraft and ship observations with atmospheric modelling to analyse how, where, and when these gases are transported from the ocean into the stratosphere.
Marta Abalos, Clara Orbe, Douglas E. Kinnison, David Plummer, Luke D. Oman, Patrick Jöckel, Olaf Morgenstern, Rolando R. Garcia, Guang Zeng, Kane A. Stone, and Martin Dameris
Atmos. Chem. Phys., 20, 6883–6901,Short summary
A set of state-of-the art chemistry–climate models is used to examine future changes in downward transport from the stratosphere, a key contributor to tropospheric ozone. The acceleration of the stratospheric circulation results in increased stratosphere-to-troposphere transport. In the subtropics, downward advection into the troposphere is enhanced due to climate change. At higher latitudes, the ozone reservoir above the tropopause is enlarged due to the stronger circulation and ozone recovery.
Karin Kreher, Michel Van Roozendael, Francois Hendrick, Arnoud Apituley, Ermioni Dimitropoulou, Udo Frieß, Andreas Richter, Thomas Wagner, Johannes Lampel, Nader Abuhassan, Li Ang, Monica Anguas, Alkis Bais, Nuria Benavent, Tim Bösch, Kristof Bognar, Alexander Borovski, Ilya Bruchkouski, Alexander Cede, Ka Lok Chan, Sebastian Donner, Theano Drosoglou, Caroline Fayt, Henning Finkenzeller, David Garcia-Nieto, Clio Gielen, Laura Gómez-Martín, Nan Hao, Bas Henzing, Jay R. Herman, Christian Hermans, Syedul Hoque, Hitoshi Irie, Junli Jin, Paul Johnston, Junaid Khayyam Butt, Fahim Khokhar, Theodore K. Koenig, Jonas Kuhn, Vinod Kumar, Cheng Liu, Jianzhong Ma, Alexis Merlaud, Abhishek K. Mishra, Moritz Müller, Monica Navarro-Comas, Mareike Ostendorf, Andrea Pazmino, Enno Peters, Gaia Pinardi, Manuel Pinharanda, Ankie Piters, Ulrich Platt, Oleg Postylyakov, Cristina Prados-Roman, Olga Puentedura, Richard Querel, Alfonso Saiz-Lopez, Anja Schönhardt, Stefan F. Schreier, André Seyler, Vinayak Sinha, Elena Spinei, Kimberly Strong, Frederik Tack, Xin Tian, Martin Tiefengraber, Jan-Lukas Tirpitz, Jeroen van Gent, Rainer Volkamer, Mihalis Vrekoussis, Shanshan Wang, Zhuoru Wang, Mark Wenig, Folkard Wittrock, Pinhua H. Xie, Jin Xu, Margarita Yela, Chengxin Zhang, and Xiaoyi Zhao
Atmos. Meas. Tech., 13, 2169–2208,Short summary
In September 2016, 36 spectrometers from 24 institutes measured a number of key atmospheric pollutants during an instrument intercomparison campaign (CINDI-2) at Cabauw, the Netherlands. Here we report on the outcome of this intercomparison exercise. The three major goals were to characterise the differences between the participating instruments, to define a robust methodology for performance assessment, and to contribute to the harmonisation of the measurement settings and retrieval methods.
Alma Hodzic, Pedro Campuzano-Jost, Huisheng Bian, Mian Chin, Peter R. Colarco, Douglas A. Day, Karl D. Froyd, Bernd Heinold, Duseong S. Jo, Joseph M. Katich, John K. Kodros, Benjamin A. Nault, Jeffrey R. Pierce, Eric Ray, Jacob Schacht, Gregory P. Schill, Jason C. Schroder, Joshua P. Schwarz, Donna T. Sueper, Ina Tegen, Simone Tilmes, Kostas Tsigaridis, Pengfei Yu, and Jose L. Jimenez
Atmos. Chem. Phys., 20, 4607–4635,Short summary
Organic aerosol (OA) is a key source of uncertainty in aerosol climate effects. We present the first pole-to-pole OA characterization during the NASA Atmospheric Tomography aircraft mission. OA has a strong seasonal and zonal variability, with the highest levels in summer and over fire-influenced regions and the lowest ones in the southern high latitudes. We show that global models predict the OA distribution well but not the relative contribution of OA emissions vs. chemical production.
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.
Alexander B. Thames, William H. Brune, David O. Miller, Hannah M. Allen, Eric C. Apel, Donald R. Blake, T. Paul Bui, Roisin Commane, John D. Crounse, Bruce C. Daube, Glenn S. Diskin, Joshua P. DiGangi, James W. Elkins, Samuel R. Hall, Thomas F. Hanisco, Reem A. Hannun, Eric Hintsa, Rebecca S. Hornbrook, Michelle J. Kim, Kathryn McKain, Fred L. Moore, Julie M. Nicely, Jeffrey Peischl, Thomas B. Ryerson, Jason M. St. Clair, Colm Sweeney, Alex Teng, Chelsea R. Thompson, Kirk Ullmann, Paul O. Wennberg, and Glenn M. Wolfe
Atmos. Chem. Phys., 20, 4013–4029,Short summary
Oceans and the atmosphere exchange volatile gases that react with the hydroxyl radical (OH). During a NASA airborne study, measurements of the total frequency of OH reactions, called the OH reactivity, were made in the marine boundary layer of the Atlantic and Pacific oceans. The measured OH reactivity often exceeded the OH reactivity calculated from measured chemical species. This missing OH reactivity appears to be from unmeasured volatile organic compounds coming out of the ocean.
Clara Orbe, David A. Plummer, Darryn W. Waugh, Huang Yang, Patrick Jöckel, Douglas E. Kinnison, Beatrice Josse, Virginie Marecal, Makoto Deushi, Nathan Luke Abraham, Alexander T. Archibald, Martyn P. Chipperfield, Sandip Dhomse, Wuhu Feng, and Slimane Bekki
Atmos. Chem. Phys., 20, 3809–3840,Short summary
Atmospheric composition is strongly influenced by global-scale winds that are not always properly simulated in computer models. A common approach to correct for this bias is to relax or
nudgeto the observed winds. Here we systematically evaluate how well this technique performs across a large suite of chemistry–climate models in terms of its ability to reproduce key aspects of both the tropospheric and stratospheric circulations.
Sinikka T. Lennartz, Christa A. Marandino, Marc von Hobe, Meinrat O. Andreae, Kazushi Aranami, Elliot Atlas, Max Berkelhammer, Heinz Bingemer, Dennis Booge, Gregory Cutter, Pau Cortes, Stefanie Kremser, Cliff S. Law, Andrew Marriner, Rafel Simó, Birgit Quack, Günther Uher, Huixiang Xie, and Xiaobin Xu
Earth Syst. Sci. Data, 12, 591–609,Short summary
Sulfur-containing trace gases in the atmosphere influence atmospheric chemistry and the energy budget of the Earth by forming aerosols. The ocean is an important source of the most abundant sulfur gas in the atmosphere, carbonyl sulfide (OCS) and its most important precursor carbon disulfide (CS2). In order to assess global variability of the sea surface concentrations of both gases to calculate their oceanic emissions, we have compiled a database of existing shipborne measurements.
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.
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.
Jian Zhu, Shanshan Wang, Hongli Wang, Shengao Jing, Shengrong Lou, Alfonso Saiz-Lopez, and Bin Zhou
Atmos. Chem. Phys., 20, 1217–1232,Short summary
To investigate the summer ozone pollution, observationally constrained modelling was carried out to study atmospheric oxidation capacity (AOC), OH reactivity, OH chain length, and HOx budget for three different ozone concentration levels in Shanghai, China. It shows that AOC, dominated by reactions involving OH radical during the daytime, has a positive correlation with ozone levels. Some key VOCs species are very important for the OH reactivity and also the ozone formation potential.
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.
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.
Qinyi Li, Rafael Borge, Golam Sarwar, David de la Paz, Brett Gantt, Jessica Domingo, Carlos A. Cuevas, and Alfonso Saiz-Lopez
Atmos. Chem. Phys., 19, 15321–15337,Short summary
The abundance and distribution of reactive halogen species and their impact on air quality in Europe are poorly understood. We adopt a state-of-the-art regional model (CMAQ) to evaluate such effects, and the results demonstrate the significant influence of halogen chemistry on the capacity of atmospheric oxidation and the formation of air pollutants in Europe. Our study highlights the necessity of including halogen chemistry in the formulation of air pollution control policy.
Yuanhong Zhao, Marielle Saunois, Philippe Bousquet, Xin Lin, Antoine Berchet, Michaela I. Hegglin, Josep G. Canadell, Robert B. Jackson, Didier A. Hauglustaine, Sophie Szopa, Ann R. Stavert, Nathan Luke Abraham, Alex T. Archibald, Slimane Bekki, Makoto Deushi, Patrick Jöckel, Béatrice Josse, Douglas Kinnison, Ole Kirner, Virginie Marécal, Fiona M. O'Connor, David A. Plummer, Laura E. Revell, Eugene Rozanov, Andrea Stenke, Sarah Strode, Simone Tilmes, Edward J. Dlugokencky, and Bo Zheng
Atmos. Chem. Phys., 19, 13701–13723,Short summary
The role of hydroxyl radical changes in methane trends is debated, hindering our understanding of the methane cycle. This study quantifies how uncertainties in the hydroxyl radical may influence methane abundance in the atmosphere based on the inter-model comparison of hydroxyl radical fields and model simulations of CH4 abundance with different hydroxyl radical scenarios during 2000–2016. We show that hydroxyl radical changes could contribute up to 54 % of model-simulated methane biases.
Joël Thanwerdas, Marielle Saunois, Antoine Berchet, Isabelle Pison, Didier Hauglustaine, Michel Ramonet, Cyril Crevoisier, Bianca Baier, Colm Sweeney, and Philippe Bousquet
Atmos. Chem. Phys. Discuss.,
Revised manuscript not acceptedShort summary
Oxidation by the hydroxyl radical (OH) is the dominant atmospheric sink for methane, contributing to approximately 90 % of the total methane loss. Chemical losses by reaction with atomic oxygen (O1D) and chlorine radicals (Cl) in the stratosphere are other sinks, contributing about 3 % to the total methane destruction. We assess here the impact of atomic Cl on atmospheric methane mixing ratios, methane atmospheric loss and atmospheric isotopic δ13C-CH4 values.
Andrea Spolaor, Elena Barbaro, David Cappelletti, Clara Turetta, Mauro Mazzola, Fabio Giardi, Mats P. Björkman, Federico Lucchetta, Federico Dallo, Katrine Aspmo Pfaffhuber, Hélène Angot, Aurelien Dommergue, Marion Maturilli, Alfonso Saiz-Lopez, Carlo Barbante, and Warren R. L. Cairns
Atmos. Chem. Phys., 19, 13325–13339,Short summary
The main aims of the study are to (a) detect whether mercury in the surface snow undergoes a daily cycle as determined in the atmosphere, (b) compare the mercury concentration in surface snow with the concentration in the atmosphere, (c) evaluate the effect of snow depositions, (d) detect whether iodine and bromine in the surface snow undergo a daily cycle, and (e) evaluate the role of metereological and atmospheric conditions. Different behaviours were determined during different seasons.
Susan S. Kulawik, Sean Crowell, David Baker, Junjie Liu, Kathryn McKain, Colm Sweeney, Sebastien C. Biraud, Steve Wofsy, Christopher W. O'Dell, Paul O. Wennberg, Debra Wunch, Coleen M. Roehl, Nicholas M. Deutscher, Matthäus Kiel, David W. T. Griffith, Voltaire A. Velazco, Justus Notholt, Thorsten Warneke, Christof Petri, Martine De Mazière, Mahesh K. Sha, Ralf Sussmann, Markus Rettinger, Dave F. Pollard, Isamu Morino, Osamu Uchino, Frank Hase, Dietrich G. Feist, Sébastien Roche, Kimberly Strong, Rigel Kivi, Laura Iraci, Kei Shiomi, Manvendra K. Dubey, Eliezer Sepulveda, Omaira Elena Garcia Rodriguez, Yao Té, Pascal Jeseck, Pauli Heikkinen, Edward J. Dlugokencky, Michael R. Gunson, Annmarie Eldering, David Crisp, Brendan Fisher, and Gregory B. Osterman
Atmos. Meas. Tech. Discuss.,
Publication in AMT not foreseenShort summary
This paper provides a benchmark of OCO-2 v8 and ACOS-GOSAT v7.3 XCO2 and lowermost tropospheric (LMT) errors. The paper focuses on the systematic errors and subtracts out validation, co-location, and random errors, looks at the correlation scale-length (spatially and temporally) of systematic errors, finding that the scale lengths are similar to bias correction scale-lengths. The assimilates of the bias correction term is used to place an error on fluxes estimates.
Eric J. Morgan, Jost V. Lavric, Damian L. Arévalo-Martínez, Hermann W. Bange, Tobias Steinhoff, Thomas Seifert, and Martin Heimann
Biogeosciences, 16, 4065–4084,Short summary
Taking a 2-year atmospheric record of atmospheric oxygen and the greenhouse gases N2O, CO2, and CH4, made at a coastal site in the Namib Desert, we estimated the fluxes of these gases from upwelling events in the northern Benguela Current region. We compared these results with flux measurements made on a research vessel in the study area at the same time and found that the two approaches agreed well. The study region was a source of N2O, CO2, and CH4 to the atmosphere during upwelling events.
Jacob K. Hedelius, Tai-Long He, Dylan B. A. Jones, Bianca C. Baier, Rebecca R. Buchholz, Martine De Mazière, Nicholas M. Deutscher, Manvendra K. Dubey, Dietrich G. Feist, David W. T. Griffith, Frank Hase, Laura T. Iraci, Pascal Jeseck, Matthäus Kiel, Rigel Kivi, Cheng Liu, Isamu Morino, Justus Notholt, Young-Suk Oh, Hirofumi Ohyama, David F. Pollard, Markus Rettinger, Sébastien Roche, Coleen M. Roehl, Matthias Schneider, Kei Shiomi, Kimberly Strong, Ralf Sussmann, Colm Sweeney, Yao Té, Osamu Uchino, Voltaire A. Velazco, Wei Wang, Thorsten Warneke, Paul O. Wennberg, Helen M. Worden, and Debra Wunch
Atmos. Meas. Tech., 12, 5547–5572,Short summary
We seek ways to improve the accuracy of column measurements of carbon monoxide (CO) – an important tracer of pollution – made from the MOPITT satellite instrument. We devise a filtering scheme which reduces the scatter and also eliminates bias among the MOPITT detectors. Compared to ground-based observations, MOPITT measurements are about 6 %–8 % higher. When MOPITT data are implemented in a global assimilation model, they tend to reduce the model mismatch with aircraft measurements.
Wenxiu Sun, Peter Hess, Gang Chen, and Simone Tilmes
Atmos. Chem. Phys., 19, 12917–12933,Short summary
Using both observations and a chemistry climate–model we establish that in most locations changes in the waviness of the 500 hPa flow field, as measured by the local anticyclonic wave activity (AWA), explain a significant fraction of the interannual variability in surface ozone over the United States. In addition, we find that the change in AWA in a future climate (circa 2100) is predicted to cause a change in surface ozone ranging between –6 ppb and 6 ppb.
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.
Andreas Chrysanthou, Amanda C. Maycock, Martyn P. Chipperfield, Sandip Dhomse, Hella Garny, Douglas Kinnison, Hideharu Akiyoshi, Makoto Deushi, Rolando R. Garcia, Patrick Jöckel, Oliver Kirner, Giovanni Pitari, David A. Plummer, Laura Revell, Eugene Rozanov, Andrea Stenke, Taichu Y. Tanaka, Daniele Visioni, and Yousuke Yamashita
Atmos. Chem. Phys., 19, 11559–11586,Short summary
We perform the first multi-model comparison of the impact of nudged meteorology on the stratospheric residual circulation (RC) in chemistry–climate models. Nudging meteorology does not constrain the mean strength of RC compared to free-running simulations, and despite the lack of agreement in the mean circulation, nudging tightly constrains the inter-annual variability in the tropical upward mass flux in the lower stratosphere. In summary, nudging strongly affects the representation of RC.
Yue Jia, Susann Tegtmeier, Elliot Atlas, and Birgit Quack
Atmos. Chem. Phys., 19, 11089–11103,
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.
Sean Crowell, David Baker, Andrew Schuh, Sourish Basu, Andrew R. Jacobson, Frederic Chevallier, Junjie Liu, Feng Deng, Liang Feng, Kathryn McKain, Abhishek Chatterjee, John B. Miller, Britton B. Stephens, Annmarie Eldering, David Crisp, David Schimel, Ray Nassar, Christopher W. O'Dell, Tomohiro Oda, Colm Sweeney, Paul I. Palmer, and Dylan B. A. Jones
Atmos. Chem. Phys., 19, 9797–9831,Short summary
Space-based retrievals of carbon dioxide offer the potential to provide dense data in regions that are sparsely observed by the surface network. We find that flux estimates that are informed by the Orbiting Carbon Observatory-2 (OCO-2) show different character from that inferred using surface measurements in tropical land regions, particularly in Africa, with a much larger total emission and larger amplitude seasonal cycle.
Ohad Harari, Chaim I. Garfinkel, Shlomi Ziskin Ziv, Olaf Morgenstern, Guang Zeng, Simone Tilmes, Douglas Kinnison, Makoto Deushi, Patrick Jöckel, Andrea Pozzer, Fiona M. O'Connor, and Sean Davis
Atmos. Chem. Phys., 19, 9253–9268,Short summary
Ozone depletion in the Antarctic has been shown to influence surface conditions, but the effects of ozone depletion in the Arctic on surface climate are unclear. We show that Arctic ozone does influence surface climate in both polar regions and tropical regions, though the proximate cause of these surface impacts is not yet clear.
Xin Chen, Dylan B. Millet, Hanwant B. Singh, Armin Wisthaler, Eric C. Apel, Elliot L. Atlas, Donald R. Blake, Ilann Bourgeois, Steven S. Brown, John D. Crounse, Joost A. de Gouw, Frank M. Flocke, Alan Fried, Brian G. Heikes, Rebecca S. Hornbrook, Tomas Mikoviny, Kyung-Eun Min, Markus Müller, J. Andrew Neuman, Daniel W. O'Sullivan, Jeff Peischl, Gabriele G. Pfister, Dirk Richter, James M. Roberts, Thomas B. Ryerson, Stephen R. Shertz, Chelsea R. Thompson, Victoria Treadaway, Patrick R. Veres, James Walega, Carsten Warneke, Rebecca A. Washenfelder, Petter Weibring, and Bin Yuan
Atmos. Chem. Phys., 19, 9097–9123,Short summary
Volatile organic compounds (VOCs) affect air quality and modify the lifetimes of other pollutants. We combine a high-resolution 3-D atmospheric model with an ensemble of aircraft observations to perform an integrated analysis of the VOC budget over North America. We find that biogenic emissions provide the main source of VOC reactivity even in most major cities. Our findings point to key gaps in current models related to oxygenated VOCs and to the distribution of VOCs in the free troposphere.
Isaac J. Vimont, Jocelyn C. Turnbull, Vasilii V. Petrenko, Philip F. Place, Colm Sweeney, Natasha Miles, Scott Richardson, Bruce H. Vaughn, and James W. C. White
Atmos. Chem. Phys., 19, 8547–8562,Short summary
Stable isotopes of Carbon Monoxide (CO) and radiocarbon carbon dioxide were measured over three summers at Indianapolis, Indiana, US, and for 1 year at a site thought to be strongly influenced by CO from oxidized volatile organic compounds (VOCs) in South Carolina, US. The Indianapolis results were used to provide an estimate of the carbon and oxygen isotopic signatures of CO produced from oxidized VOCs. This updated estimate agrees well with the data from South Carolina during the summer.
Thomas Wagner, Steffen Beirle, Nuria Benavent, Tim Bösch, Ka Lok Chan, Sebastian Donner, Steffen Dörner, Caroline Fayt, Udo Frieß, David García-Nieto, Clio Gielen, David González-Bartolome, Laura Gomez, François Hendrick, Bas Henzing, Jun Li Jin, Johannes Lampel, Jianzhong Ma, Kornelia Mies, Mónica Navarro, Enno Peters, Gaia Pinardi, Olga Puentedura, Janis Puķīte, Julia Remmers, Andreas Richter, Alfonso Saiz-Lopez, Reza Shaiganfar, Holger Sihler, Michel Van Roozendael, Yang Wang, and Margarita Yela
Atmos. Meas. Tech., 12, 2745–2817,Short summary
In this study the consistency between MAX-DOAS measurements and radiative transfer simulations of the atmospheric O4 absorption is investigated. The study is based on measurements (2 selected days during the MADCAT campaign) as well as synthetic spectra. The uncertainties of all relevant aspects (spectral retrieval and radiative transfer simulations) are quantified. For one of the selected days, measurements and simulations do not agree within their uncertainties.
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.
Marianna Linz, Marta Abalos, Anne Sasha Glanville, Douglas E. Kinnison, Alison Ming, and Jessica L. Neu
Atmos. Chem. Phys., 19, 5069–5090,Short summary
The stratospheric circulation is important for transporting ozone and water vapor, and models of the stratosphere differ. The metrics used to compare models are inconsistent between studies and cannot be calculated from observational data. In this paper, we explore a metric for the circulation that can be calculated from observations and examine how it relates to the more commonly used metrics. We find substantial differences in the upper and lower stratosphere depending on the choice of metric.
Lucien Froidevaux, Douglas E. Kinnison, Ray Wang, John Anderson, and Ryan A. Fuller
Atmos. Chem. Phys., 19, 4783–4821,Short summary
This work evaluates two versions of a 3-D global model of upper-atmospheric composition for recent decades. The two versions differ mainly in their dynamical (wind) constraints. Model–data differences, variability, and trends in five gases (ozone, H2O, HCl, HNO3, and N2O) are compared. While the match between models and observations is impressive, a few areas of discrepancy are noted. This work also updates trends in composition based on recent satellite-based measurements (through 2018).
Julian Kostinek, Anke Roiger, Kenneth J. Davis, Colm Sweeney, Joshua P. DiGangi, Yonghoon Choi, Bianca Baier, Frank Hase, Jochen Groß, Maximilian Eckl, Theresa Klausner, and André Butz
Atmos. Meas. Tech., 12, 1767–1783,Short summary
We demonstrate the successful adaption of a laser-based spectrometer for airborne in situ trace gas measurements. The modified instrument allows for precise and simultaneous airborne observation of five climatologically relevant gases. We further report on instrument performance during a first field deployment over the eastern and central USA.
Alba Badia, Claire E. Reeves, Alex R. Baker, Alfonso Saiz-Lopez, Rainer Volkamer, Theodore K. Koenig, Eric C. Apel, Rebecca S. Hornbrook, Lucy J. Carpenter, Stephen J. Andrews, Tomás Sherwen, and Roland von Glasow
Atmos. Chem. Phys., 19, 3161–3189,Short summary
The oceans have an impact on the composition and reactivity of the troposphere through the emission of gases and particles. Thus, a quantitative understanding of the marine atmosphere is crucial to examine the oxidative capacity and climate forcing. This study investigates the impact of halogens in the tropical troposphere and explores the sensitivity of this to uncertainties in the fluxes and their chemical processing. Our modelled tropospheric Ox loss due to halogens ranges from 20 % to 60 %.
Anna Karion, Thomas Lauvaux, Israel Lopez Coto, Colm Sweeney, Kimberly Mueller, Sharon Gourdji, Wayne Angevine, Zachary Barkley, Aijun Deng, Arlyn Andrews, Ariel Stein, and James Whetstone
Atmos. Chem. Phys., 19, 2561–2576,Short summary
In this study, we use atmospheric methane concentration observations collected during an airborne campaign to compare different model-based emissions estimates from the Barnett Shale oil and natural gas production basin in Texas, USA. We find that the tracer dispersion model has a significant impact on the results because the models differ in their simulation of vertical dispersion. Additional work is needed to evaluate and improve vertical mixing in the tracer dispersion models.
Nicole S. Lovenduski, Stephen G. Yeager, Keith Lindsay, and Matthew C. Long
Earth Syst. Dynam., 10, 45–57,Short summary
This paper shows that the absorption of carbon dioxide by the ocean is predictable several years in advance. This is important because fossil-fuel-derived carbon dioxide is largely responsible for anthropogenic global warming and because carbon dioxide emission management and global carbon cycle budgeting exercises can benefit from foreknowledge of ocean carbon absorption. The promising results from this new forecast system justify the need for additional oceanic observations.
Roland Eichinger, Simone Dietmüller, Hella Garny, Petr Šácha, Thomas Birner, Harald Bönisch, Giovanni Pitari, Daniele Visioni, Andrea Stenke, Eugene Rozanov, Laura Revell, David A. Plummer, Patrick Jöckel, Luke Oman, Makoto Deushi, Douglas E. Kinnison, Rolando Garcia, Olaf Morgenstern, Guang Zeng, Kane Adam Stone, and Robyn Schofield
Atmos. Chem. Phys., 19, 921–940,Short summary
To shed more light upon the changes in stratospheric circulation in the 21st century, climate projection simulations of 10 state-of-the-art global climate models, spanning from 1960 to 2100, are analyzed. The study shows that in addition to changes in transport, mixing also plays an important role in stratospheric circulation and that the properties of mixing vary over time. Furthermore, the influence of mixing is quantified and a dynamical framework is provided to understand the changes.
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.
Benjamin Gaubert, Britton B. Stephens, Sourish Basu, Frédéric Chevallier, Feng Deng, Eric A. Kort, Prabir K. Patra, Wouter Peters, Christian Rödenbeck, Tazu Saeki, David Schimel, Ingrid Van der Laan-Luijkx, Steven Wofsy, and Yi Yin
Biogeosciences, 16, 117–134,Short summary
We have compared global carbon budgets calculated from numerical inverse models and CO2 observations, and evaluated how these systems reproduce vertical gradients in atmospheric CO2 from aircraft measurements. We found that available models have converged on near-neutral tropical total fluxes for several decades, implying consistent sinks in intact tropical forests, and that assumed fossil fuel emissions and predicted atmospheric growth rates are now the dominant axes of disagreement.
Corinne Le Quéré, Robbie M. Andrew, Pierre Friedlingstein, Stephen Sitch, Judith Hauck, Julia Pongratz, Penelope A. Pickers, Jan Ivar Korsbakken, Glen P. Peters, Josep G. Canadell, Almut Arneth, Vivek K. Arora, Leticia Barbero, Ana Bastos, Laurent Bopp, Frédéric Chevallier, Louise P. Chini, Philippe Ciais, Scott C. Doney, Thanos Gkritzalis, Daniel S. Goll, Ian Harris, Vanessa Haverd, Forrest M. Hoffman, Mario Hoppema, Richard A. Houghton, George Hurtt, Tatiana Ilyina, Atul K. Jain, Truls Johannessen, Chris D. Jones, Etsushi Kato, Ralph F. Keeling, Kees Klein Goldewijk, Peter Landschützer, Nathalie Lefèvre, Sebastian Lienert, Zhu Liu, Danica Lombardozzi, Nicolas Metzl, David R. Munro, Julia E. M. S. Nabel, Shin-ichiro Nakaoka, Craig Neill, Are Olsen, Tsueno Ono, Prabir Patra, Anna Peregon, Wouter Peters, Philippe Peylin, Benjamin Pfeil, Denis Pierrot, Benjamin Poulter, Gregor Rehder, Laure Resplandy, Eddy Robertson, Matthias Rocher, Christian Rödenbeck, Ute Schuster, Jörg Schwinger, Roland Séférian, Ingunn Skjelvan, Tobias Steinhoff, Adrienne Sutton, Pieter P. Tans, Hanqin Tian, Bronte Tilbrook, Francesco N. Tubiello, Ingrid T. van der Laan-Luijkx, Guido R. van der Werf, Nicolas Viovy, Anthony P. Walker, Andrew J. Wiltshire, Rebecca Wright, Sönke Zaehle, and Bo Zheng
Earth Syst. Sci. Data, 10, 2141–2194,Short summary
The Global Carbon Budget 2018 describes the data sets and methodology used to quantify the emissions of carbon dioxide and their partitioning among the atmosphere, land, and ocean. These living data are updated every year to provide the highest transparency and traceability in the reporting of CO2, the key driver of climate change.
Dien Wu, John C. Lin, Benjamin Fasoli, Tomohiro Oda, Xinxin Ye, Thomas Lauvaux, Emily G. Yang, and Eric A. Kort
Geosci. Model Dev., 11, 4843–4871,Short summary
Urban CO2 enhancement signals can be derived using satellite column CO2 concentrations and atmospheric transport models. However, uncertainties due to model configurations, atmospheric transport, and defined background values can potentially impact the derived urban signals. In this paper, we present a modified Lagrangian model framework that extracts urban CO2 signals from satellite observations and determines potential error impacts.
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.
Cristina Carnerero, Noemí Pérez, Cristina Reche, Marina Ealo, Gloria Titos, Hong-Ku Lee, Hee-Ram Eun, Yong-Hee Park, Lubna Dada, Pauli Paasonen, Veli-Matti Kerminen, Enrique Mantilla, Miguel Escudero, Francisco J. Gómez-Moreno, Elisabeth Alonso-Blanco, Esther Coz, Alfonso Saiz-Lopez, Brice Temime-Roussel, Nicolas Marchand, David C. S. Beddows, Roy M. Harrison, Tuukka Petäjä, Markku Kulmala, Kang-Ho Ahn, Andrés Alastuey, and Xavier Querol
Atmos. Chem. Phys., 18, 16601–16618,Short summary
The vertical distribution of new particle formation events was studied using tethered balloons carrying miniaturized instrumentation. Results show that new particle formation and growth occurs only in the lower layer of the atmosphere, where aerosols are mixed due to convection, especially when the atmosphere is clean. A comparison of urban and suburban surface stations was also made, suggesting that such events may have a significant impact on ultrafine particle concentrations in a wide area.
Laura E. Revell, Andrea Stenke, Fiona Tummon, Aryeh Feinberg, Eugene Rozanov, Thomas Peter, N. Luke Abraham, Hideharu Akiyoshi, Alexander T. Archibald, Neal Butchart, Makoto Deushi, Patrick Jöckel, Douglas Kinnison, Martine Michou, Olaf Morgenstern, Fiona M. O'Connor, Luke D. Oman, Giovanni Pitari, David A. Plummer, Robyn Schofield, Kane Stone, Simone Tilmes, Daniele Visioni, Yousuke Yamashita, and Guang Zeng
Atmos. Chem. Phys., 18, 16155–16172,Short summary
Global models such as those participating in the Chemistry-Climate Model Initiative (CCMI) consistently simulate biases in tropospheric ozone compared with observations. We performed an advanced statistical analysis with one of the CCMI models to understand the cause of the bias. We found that emissions of ozone precursor gases are the dominant driver of the bias, implying either that the emissions are too large, or that the way in which the model handles emissions needs to be improved.
Alexander Gvakharia, Eric A. Kort, Mackenzie L. Smith, and Stephen Conley
Atmos. Meas. Tech., 11, 6059–6074,Short summary
We present a new flight system to measure the atmospheric trace gases N2O, CO2, CO, and H2O. We use a novel calibration technique to correct altitude-dependent artifacts that have hindered similar instruments. In-flight null-tests and comparison with other flight-proven instruments provide validation. This high-precision, high-accuracy system provides opportunities for airborne studies to improve our understanding of N2O emission processes.
Christine D. Groot Zwaaftink, Stephan Henne, Rona L. Thompson, Edward J. Dlugokencky, Toshinobu Machida, Jean-Daniel Paris, Motoki Sasakawa, Arjo Segers, Colm Sweeney, and Andreas Stohl
Geosci. Model Dev., 11, 4469–4487,Short summary
A Lagrangian particle dispersion model is used to simulate global fields of methane, constrained by observations through nudging. We show that this rather simple and computationally inexpensive method can give results similar to or as good as a computationally expensive Eulerian chemistry transport model with a data assimilation scheme. The three-dimensional methane fields are of interest to applications such as inverse modelling and satellite retrievals.
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.
Daniele Visioni, Giovanni Pitari, Glauco di Genova, Simone Tilmes, and Irene Cionni
Atmos. Chem. Phys., 18, 14867–14887,Short summary
Many side effects of sulfate geoengineering have to be analyzed before the world can even consider deploying this method of solar radiation management. In particular, we show that ice clouds in the upper troposphere are modified by a sulfate injection, producing a change that (by allowing for more planetary radiation to escape to space) would produce a further cooling. This might be important when considering the necessary amount of sulfate that needs to be injected to achieve a certain target.
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.
Liang Feng, Paul I. Palmer, Robyn Butler, Stephen J. Andrews, Elliot L. Atlas, Lucy J. Carpenter, Valeria Donets, Neil R. P. Harris, Ross J. Salawitch, Laura L. Pan, and Sue M. Schauffler
Atmos. Chem. Phys., 18, 14787–14798,Short summary
We infer surface fluxes of bromoform (CHBr3) and dibromoform (CH2Br2) from CAST and CONTRAST aircraft observations over the western Pacific, using a tagged version of the GEOS-Chem global 3-D atmospheric chemistry model and a Maximum A Posteriori inverse model. Using the aircraft data, we estimate the regional fluxes about 20–40 % smaller than the prior inventories by Ordóñez et al. (2012). We find no evidence to support a robust linear relationship between CHBr3 and CH2Br2 oceanic emissions.
Robyn Butler, Paul I. Palmer, Liang Feng, Stephen J. Andrews, Elliot L. Atlas, Lucy J. Carpenter, Valeria Donets, Neil R. P. Harris, Stephen A. Montzka, Laura L. Pan, Ross J. Salawitch, and Sue M. Schauffler
Atmos. Chem. Phys., 18, 13135–13153,Short summary
Natural sources of short-lived bromoform and dibromomethane are important for determining the inorganic bromine budget in the stratosphere that drives ozone loss. Two new modelling techniques describe how different geographical source regions influence their atmospheric variability over the western Pacific. We find that it is driven primarily by open ocean sources, and we use atmospheric observations to help estimate their contributions to the upper tropospheric inorganic bromine budget.
Wei He, Ivar R. van der Velde, Arlyn E. Andrews, Colm Sweeney, John Miller, Pieter Tans, Ingrid T. van der Laan-Luijkx, Thomas Nehrkorn, Marikate Mountain, Weimin Ju, Wouter Peters, and Huilin Chen
Geosci. Model Dev., 11, 3515–3536,Short summary
We have implemented a regional, high-resolution, and computationally attractive carbon dioxide data assimilation system. This system, named CTDAS-Lagrange, is capable of simultaneously optimizing terrestrial biosphere fluxes and the lateral boundary conditions. The CTDAS-Lagrange system can be easily extended to assimilate an additional tracer, e.g., carbonyl sulfide (COS or OCS), for regional estimates of both net and gross carbon fluxes.
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.
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.
Chunxiang Ye, Xianliang Zhou, Dennis Pu, Jochen Stutz, James Festa, Max Spolaor, Catalina Tsai, Christopher Cantrell, Roy L. Mauldin III, Andrew Weinheimer, Rebecca S. Hornbrook, Eric C. Apel, Alex Guenther, Lisa Kaser, Bin Yuan, Thomas Karl, Julie Haggerty, Samuel Hall, Kirk Ullmann, James Smith, and John Ortega
Atmos. Chem. Phys., 18, 9107–9120,Short summary
Substantial levels of HONO existed during the day throughout the troposphere over the southeastern US during NOMADSS 2013. Particulate nitrate photolysis appeared to be the major volume HONO source, while NOx was an important HONO precursor only in industrial and urban plumes. HONO was not a significant OH radical precursor in the rural troposphere away from the ground surface; however, its production from particulate nitrate photolysis was an important renoxification pathway.
Steven T. Turnock, Oliver Wild, Frank J. Dentener, Yanko Davila, Louisa K. Emmons, Johannes Flemming, Gerd A. Folberth, Daven K. Henze, Jan E. Jonson, Terry J. Keating, Sudo Kengo, Meiyun Lin, Marianne Lund, Simone Tilmes, and Fiona M. O'Connor
Atmos. Chem. Phys., 18, 8953–8978,Short summary
A simple parameterisation was developed in this study to provide a rapid assessment of the impacts and uncertainties associated with future emission control strategies by predicting changes to surface ozone air quality and near-term climate forcing of ozone. Future emissions scenarios based on currently implemented legislation are shown to worsen surface ozone air quality and enhance near-term climate warming, with changes in methane becoming increasingly important in the future.
Amanda R. Fay, Nicole S. Lovenduski, Galen A. McKinley, David R. Munro, Colm Sweeney, Alison R. Gray, Peter Landschützer, Britton B. Stephens, Taro Takahashi, and Nancy Williams
Biogeosciences, 15, 3841–3855,Short summary
The Southern Ocean is highly under-sampled and since this region dominates the ocean sink for CO2, understanding change is critical. Here we utilize available observations to evaluate how the seasonal cycle, variability, and trends in surface ocean carbon in the well-sampled Drake Passage region compare to that of the broader subpolar Southern Ocean. Results indicate that the Drake Passage is representative of the broader region; however, additional winter observations would improve comparisons.
Jens-Uwe Grooß, Rolf Müller, Reinhold Spang, Ines Tritscher, Tobias Wegner, Martyn P. Chipperfield, Wuhu Feng, Douglas E. Kinnison, and Sasha Madronich
Atmos. Chem. Phys., 18, 8647–8666,Short summary
We investigate a discrepancy between model simulations and observations of HCl in the dark polar stratosphere. In early winter, the less-well-studied period of the onset of chlorine activation, observations show a much faster depletion of HCl than simulations of three models. This points to some unknown process that is currently not represented in the models. Various hypotheses for potential causes are investigated that partly reduce the discrepancy. The impact on polar ozone depletion is low.
Benjamin Brown-Steiner, Noelle E. Selin, Ronald G. Prinn, Erwan Monier, Simone Tilmes, Louisa Emmons, and Fernando Garcia-Menendez
Atmos. Chem. Phys., 18, 8373–8388,Short summary
Detecting signals in observations and simulations of atmospheric chemistry is difficult due to the underlying variability in the chemistry, meteorology, and climatology. Here we examine the scale dependence of ozone variability and explore strategies for reducing or averaging this variability and thereby enhancing ozone signal detection capabilities. We find that 10–15 years of temporal averaging, and some level of spatial averaging, reduces the risk of overconfidence in ozone signals.
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.
Stefan Lossow, Dale F. Hurst, Karen H. Rosenlof, Gabriele P. Stiller, Thomas von Clarmann, Sabine Brinkop, Martin Dameris, Patrick Jöckel, Doug E. Kinnison, Johannes Plieninger, David A. Plummer, Felix Ploeger, William G. Read, Ellis E. Remsberg, James M. Russell, and Mengchu Tao
Atmos. Chem. Phys., 18, 8331–8351,Short summary
Trend estimates of lower stratospheric H2O derived from the FPH observations at Boulder and a merged zonal mean satellite data set clearly differ for the time period from the late 1980s to 2010. We investigate if a sampling bias between Boulder and the zonal mean around the Boulder latitude can explain these trend discrepancies. Typically they are small and not sufficient to explain the trend discrepancies in the observational database.
Roya Bahreini, Ravan Ahmadov, Stu A. McKeen, Kennedy T. Vu, Justin H. Dingle, Eric C. Apel, Donald R. Blake, Nicola Blake, Teresa L. Campos, Chris Cantrell, Frank Flocke, Alan Fried, Jessica B. Gilman, Alan J. Hills, Rebecca S. Hornbrook, Greg Huey, Lisa Kaser, Brian M. Lerner, Roy L. Mauldin, Simone Meinardi, Denise D. Montzka, Dirk Richter, Jason R. Schroeder, Meghan Stell, David Tanner, James Walega, Peter Weibring, and Andrew Weinheimer
Atmos. Chem. Phys., 18, 8293–8312,Short summary
We measured organic aerosol (OA) and relevant trace gases during FRAPPÉ in the Colorado Front Range, with the goal of characterizing summertime OA formation. Our results indicate a significant production of secondary OA (SOA) in this region. About 2 μg m−3 of OA was present at background CO levels, suggesting contribution of non-combustion sources to SOA. Contribution of oil- and gas-related activities to anthropogenic SOA was modeled to be ~38 %. Biogenic SOA contributed to >40 % of OA.
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.
Simone Dietmüller, Roland Eichinger, Hella Garny, Thomas Birner, Harald Boenisch, Giovanni Pitari, Eva Mancini, Daniele Visioni, Andrea Stenke, Laura Revell, Eugene Rozanov, David A. Plummer, John Scinocca, Patrick Jöckel, Luke Oman, Makoto Deushi, Shibata Kiyotaka, Douglas E. Kinnison, Rolando Garcia, Olaf Morgenstern, Guang Zeng, Kane Adam Stone, and Robyn Schofield
Atmos. Chem. Phys., 18, 6699–6720,
Xavier Querol, Andrés Alastuey, Gotzon Gangoiti, Noemí Perez, Hong K. Lee, Heeram R. Eun, Yonghee Park, Enrique Mantilla, Miguel Escudero, Gloria Titos, Lucio Alonso, Brice Temime-Roussel, Nicolas Marchand, Juan R. Moreta, M. Arantxa Revuelta, Pedro Salvador, Begoña Artíñano, Saúl García dos Santos, Mónica Anguas, Alberto Notario, Alfonso Saiz-Lopez, Roy M. Harrison, Millán Millán, and Kang-Ho Ahn
Atmos. Chem. Phys., 18, 6511–6533,Short summary
We show the main drivers of high O3 episodes in and around Madrid. High levels of ultrafine particles (UFPs) are evidenced, but we demonstrate that most O3 arises from the fumigation of high atmospheric layers, whereas UFPs are generated inside the PBL. O3 contributions from the fumigation of the vertical recirculation of regional air masses, hemispheric transport, and horizontally from direct urban plume transport are shown. Complexity arises from the need to quantify them to abate surface O3.
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.
Martin G. Schultz, Scarlet Stadtler, Sabine Schröder, Domenico Taraborrelli, Bruno Franco, Jonathan Krefting, Alexandra Henrot, Sylvaine Ferrachat, Ulrike Lohmann, David Neubauer, Colombe Siegenthaler-Le Drian, Sebastian Wahl, Harri Kokkola, Thomas Kühn, Sebastian Rast, Hauke Schmidt, Philip Stier, Doug Kinnison, Geoffrey S. Tyndall, John J. Orlando, and Catherine Wespes
Geosci. Model Dev., 11, 1695–1723,Short summary
The chemistry–climate model ECHAM-HAMMOZ contains a detailed representation of tropospheric and stratospheric reactive chemistry and state-of-the-art parameterizations of aerosols. It thus allows for detailed investigations of chemical processes in the climate system. Evaluation of the model with various observational data yields good results, but the model has a tendency to produce too much OH in the tropics. This highlights the important interplay between atmospheric chemistry and dynamics.
Fernando Iglesias-Suarez, Douglas E. Kinnison, Alexandru Rap, Amanda C. Maycock, Oliver Wild, and Paul J. Young
Atmos. Chem. Phys., 18, 6121–6139,Short summary
This study explores future ozone radiative forcing (RF) and the relative contribution due to different drivers. Climate-induced ozone RF is largely the result of the interplay between lightning-produced ozone and enhanced ozone destruction in a warmer and wetter atmosphere. These results demonstrate the importance of stratospheric–tropospheric interactions and the stratosphere as a key region controlling a large fraction of the tropospheric ozone RF.
Christian Rödenbeck, Sönke Zaehle, Ralph Keeling, and Martin Heimann
Biogeosciences, 15, 2481–2498,Short summary
In this paper we investigate how the CO2 exchange between the land vegetation and the atmosphere varies from year to year. We quantify the relation between variations in the CO2 exchange and variations in air temperature. For this quantification, we use long-term measurements of CO2 in the air at many locations, a simulation code for the transport of carbon dioxide through the atmosphere, and a data set of air temperature. The results help us to understand the mechanisms of CO2 exchange.
Richard Newton, Geraint Vaughan, Eric Hintsa, Michal T. Filus, Laura L. Pan, Shawn Honomichl, Elliot Atlas, Stephen J. Andrews, and Lucy J. Carpenter
Atmos. Chem. Phys., 18, 5157–5171,Short summary
We consider the ozone measurements from aircraft during the CAST/CONTRAST/ATTREX campaigns of 2014. Low concentrations of ozone were found in the layer of 10–15 km altitude, which is indicative of uplift of ozone-poor air from near the sea surface to 10–15 km altitude. Chemicals that have origins in the sea were found in greater abundance when ozone concentrations were low compared to when ozone concentrations were high. The lowest ozone concentrations were found in the Southern Hemisphere.
Caroline B. Alden, Subhomoy Ghosh, Sean Coburn, Colm Sweeney, Anna Karion, Robert Wright, Ian Coddington, Gregory B. Rieker, and Kuldeep Prasad
Atmos. Meas. Tech., 11, 1565–1582,Short summary
The location and sizing leaks of methane from natural gas operations poses a real challenge for greenhouse gas emission mitigation efforts and for accurate quantification of emissions inventories. We demonstrate, with synthetic and field tests, a new statistical method for the location and sizing of small trace gas point sources dispersed over large areas, based on measurements of ambient atmospheric conditions made with long-range, open-path laser-based atmospheric observations.
Corinne Le Quéré, Robbie M. Andrew, Pierre Friedlingstein, Stephen Sitch, Julia Pongratz, Andrew C. Manning, Jan Ivar Korsbakken, Glen P. Peters, Josep G. Canadell, Robert B. Jackson, Thomas A. Boden, Pieter P. Tans, Oliver D. Andrews, Vivek K. Arora, Dorothee C. E. Bakker, Leticia Barbero, Meike Becker, Richard A. Betts, Laurent Bopp, Frédéric Chevallier, Louise P. Chini, Philippe Ciais, Catherine E. Cosca, Jessica Cross, Kim Currie, Thomas Gasser, Ian Harris, Judith Hauck, Vanessa Haverd, Richard A. Houghton, Christopher W. Hunt, George Hurtt, Tatiana Ilyina, Atul K. Jain, Etsushi Kato, Markus Kautz, Ralph F. Keeling, Kees Klein Goldewijk, Arne Körtzinger, Peter Landschützer, Nathalie Lefèvre, Andrew Lenton, Sebastian Lienert, Ivan Lima, Danica Lombardozzi, Nicolas Metzl, Frank Millero, Pedro M. S. Monteiro, David R. Munro, Julia E. M. S. Nabel, Shin-ichiro Nakaoka, Yukihiro Nojiri, X. Antonio Padin, Anna Peregon, Benjamin Pfeil, Denis Pierrot, Benjamin Poulter, Gregor Rehder, Janet Reimer, Christian Rödenbeck, Jörg Schwinger, Roland Séférian, Ingunn Skjelvan, Benjamin D. Stocker, Hanqin Tian, Bronte Tilbrook, Francesco N. Tubiello, Ingrid T. van der Laan-Luijkx, Guido R. van der Werf, Steven van Heuven, Nicolas Viovy, Nicolas Vuichard, Anthony P. Walker, Andrew J. Watson, Andrew J. Wiltshire, Sönke Zaehle, and Dan Zhu
Earth Syst. Sci. Data, 10, 405–448,Short summary
The Global Carbon Budget 2017 describes data sets and methodology to quantify the five major components of the global carbon budget and their uncertainties. It is the 12th annual update and the 6th published in this journal.
Natasha L. Miles, Douglas K. Martins, Scott J. Richardson, Christopher W. Rella, Caleb Arata, Thomas Lauvaux, Kenneth J. Davis, Zachary R. Barkley, Kathryn McKain, and Colm Sweeney
Atmos. Meas. Tech., 11, 1273–1295,Short summary
Analyzers measuring methane and methane isotopic ratio were deployed at four towers in the Marcellus Shale natural gas extraction region of Pennsylvania. The methane isotopic ratio is helpful for differentiating emissions from natural gas activities from other sources (e.g., landfills). We describe the analyzer calibration. The signals observed in the study region were generally small, but the instrumental performance demonstrated here could be used in regions with stronger enhancements.
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.
Niall J. Ryan, Douglas E. Kinnison, Rolando R. Garcia, Christoph G. Hoffmann, Mathias Palm, Uwe Raffalski, and Justus Notholt
Atmos. Chem. Phys., 18, 1457–1474,Short summary
We used model output and instrument data to assess how well polar atmospheric descent rates can be derived using concentration measurements of long-lived gases in the atmosphere. The results indicate that the method incurs errors as large as the descent rates, and often leads to a misinterpretation of the direction of air motion. The rates derived using this method do not appear to represent the mean vertical wind in the middle atmosphere, and we suggest an alternate definition.
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.
Sean Hartery, Róisín Commane, Jakob Lindaas, Colm Sweeney, John Henderson, Marikate Mountain, Nicholas Steiner, Kyle McDonald, Steven J. Dinardo, Charles E. Miller, Steven C. Wofsy, and Rachel Y.-W. Chang
Atmos. Chem. Phys., 18, 185–202,Short summary
Methane is the second most important greenhouse gas but its emissions from northern regions are still poorly constrained. This study uses aircraft measurements of methane from Alaska to estimate surface emissions. We found that methane emission rates depend on the soil temperature at depths where its production was taking place, and that total emissions were similar between tundra and boreal regions. These results provide a simple way to predict methane emissions in this region.
Justin Bandoro, Susan Solomon, Benjamin D. Santer, Douglas E. Kinnison, and Michael J. Mills
Atmos. Chem. Phys., 18, 143–166,Short summary
We studied the attribution of stratospheric ozone changes and identified similarities between observations and human fingerprints from both emissions of ozone-depleting substances (ODSs) and greenhouse gases (GHGs). We developed an improvement on the traditional pattern correlation method that accounts for nonlinearities in the climate forcing time evolution. Use of the latter resulted in increased S / N ratios for the ODS fingerprint. The GHG fingerprint was not identifiable.
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.
Xin Lan, Pieter Tans, Colm Sweeney, Arlyn Andrews, Andrew Jacobson, Molly Crotwell, Edward Dlugokencky, Jonathan Kofler, Patricia Lang, Kirk Thoning, and Sonja Wolter
Atmos. Chem. Phys., 17, 15151–15165,Short summary
We analyze spatial patterns of column CO2 over North America using well-calibrated aircraft and tall tower measurements. We find that the long-term averaged spatial gradients of column CO2 across North America show a smooth pattern that mainly reflects the large-scale circulation. Our results can serve as a good reference for evaluating current and future column CO2 retrievals from both ground and satellite platforms.
Xinxin Ye, Thomas Lauvaux, Eric A. Kort, Tomohiro Oda, Sha Feng, John C. Lin, Emily Yang, and Dien Wu
Atmos. Chem. Phys. Discuss.,
Revised manuscript not acceptedShort summary
Rapid global urbanization and significant fossil fuel consumption by cities emphasize the necessity of achieving independent and accurate quantification of the carbon emissions from urban areas. In this paper, we assess the potential of using total column CO2 concentration observed from satellite to quantify fossil-fuel carbon emissions from cities. This study could give insights into the capability of satellite observations on monitoring of the emissions on local scale.
Heather Graven, Colin E. Allison, David M. Etheridge, Samuel Hammer, Ralph F. Keeling, Ingeborg Levin, Harro A. J. Meijer, Mauro Rubino, Pieter P. Tans, Cathy M. Trudinger, Bruce H. Vaughn, and James W. C. White
Geosci. Model Dev., 10, 4405–4417,Short summary
Modelling of carbon isotopes 13C and 14C in land and ocean components of Earth system models provides opportunities for new insights and improved understanding of global carbon cycling, and for model evaluation. We compiled existing historical datasets to define the annual mean carbon isotopic composition of atmospheric CO2 for 1850–2015 that can be used in CMIP6 and other modelling activities.
Zachary R. Barkley, Thomas Lauvaux, Kenneth J. Davis, Aijun Deng, Natasha L. Miles, Scott J. Richardson, Yanni Cao, Colm Sweeney, Anna Karion, MacKenzie Smith, Eric A. Kort, Stefan Schwietzke, Thomas Murphy, Guido Cervone, Douglas Martins, and Joannes D. Maasakkers
Atmos. Chem. Phys., 17, 13941–13966,Short summary
This study quantifies methane emissions from natural gas production in north-eastern Pennsylvania. Methane observations from 10 flights in spring 2015 are compared to model-projected values, and methane emissions from natural gas are adjusted within the model to create the best match between the two data sets. This study find methane emissions from natural gas production to be low and may be indicative of characteristics of the basin that make sources from north-eastern Pennsylvania unique.
Andrew K. Thorpe, Christian Frankenberg, David R. Thompson, Riley M. Duren, Andrew D. Aubrey, Brian D. Bue, Robert O. Green, Konstantin Gerilowski, Thomas Krings, Jakob Borchardt, Eric A. Kort, Colm Sweeney, Stephen Conley, Dar A. Roberts, and Philip E. Dennison
Atmos. Meas. Tech., 10, 3833–3850,Short summary
At local scales emissions of methane (CH4) and carbon dioxide (CO2) are highly uncertain. The AVIRIS-NG imaging spectrometer maps large regions and generates high-spatial-resolution CH4 and CO2 concentration maps from anthropogenic and natural sources. Examples include CH4 from a processing plant, tank, pipeline leak, seep, mine vent shafts, and CO2 from power plants. This demonstrates a greenhouse gas monitoring capability that targets the two dominant anthropogenic climate-forcing agents.
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.
Lili Xia, Peer J. Nowack, Simone Tilmes, and Alan Robock
Atmos. Chem. Phys., 17, 11913–11928,Short summary
Ozone is a key air pollutant. We model two geoengineering schemes, stratospheric sulfur injection and solar irradiance reduction, to compare their impacts on atmospheric ozone concentrations. With the nearly identical global mean surface temperature reduction, solar dimming increases global average surface ozone concentration, while sulfate injection decreases it. This difference is due to different stratosphere–troposphere exchange of ozone and tropospheric ozone chemistry in the two scenarios.
Bianca C. Baier, William H. Brune, David O. Miller, Donald Blake, Russell Long, Armin Wisthaler, Christopher Cantrell, Alan Fried, Brian Heikes, Steven Brown, Erin McDuffie, Frank Flocke, Eric Apel, Lisa Kaser, and Andrew Weinheimer
Atmos. Chem. Phys., 17, 11273–11292,Short summary
Ozone production rates were measured using the Measurement of Ozone Production Sensor (MOPS). Measurements are compared to modeled ozone production rates using two different chemical mechanisms. At high nitric oxide levels, observed rates are higher than those modeled, prompting the need to revisit current model photochemistry. These direct measurements can add to our understanding of the ozone chemistry within air quality models and can be used to guide government regulatory strategies.
Daniele Visioni, Giovanni Pitari, Valentina Aquila, Simone Tilmes, Irene Cionni, Glauco Di Genova, and Eva Mancini
Atmos. Chem. Phys., 17, 11209–11226,Short summary
Sulfate geoengineering (SG), the sustained injection of SO2 in the lower stratosphere, is being discussed as a way to counterbalance surface warming, mimicking volcanic eruptions. In this paper, we analyse results from two models part of the GeoMIP project in order to understand the effect SG might have on the concentration and lifetime of methane, which acts in the atmosphere as a greenhouse gas. Understanding possible side effects of SG is a crucial step if its viability is to be assessed.
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.
Stephen Conley, Ian Faloona, Shobhit Mehrotra, Maxime Suard, Donald H. Lenschow, Colm Sweeney, Scott Herndon, Stefan Schwietzke, Gabrielle Pétron, Justin Pifer, Eric A. Kort, and Russell Schnell
Atmos. Meas. Tech., 10, 3345–3358,Short summary
This paper describes a new method of quantifying surface trace gas emissions (e.g. methane) from small aircraft (e.g. Mooney, Cessna) in about 30 min. This technique greatly enhances our ability to rapidly respond in the event of catastrophic failures such as Aliso Canyon and Deep Water Horizon.
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.
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.
Merritt N. Deeter, David P. Edwards, Gene L. Francis, John C. Gille, Sara Martínez-Alonso, Helen M. Worden, and Colm Sweeney
Atmos. Meas. Tech., 10, 2533–2555,Short summary
This manuscript describes the methods used for deriving the latest version 7 product for atmospheric carbon monoxide (CO) from measurements made by the MOPITT (Measurements of Pollution in the Troposphere) satellite instrument. Comparisons of MOPITT-retrieved CO vertical profiles with in situ data measured from aircraft are also presented, and they demonstrate clear improvements relative to earlier MOPITT products. The new CO product is appropriate for a wide variety of applications.
Kristal R. Verhulst, Anna Karion, Jooil Kim, Peter K. Salameh, Ralph F. Keeling, Sally Newman, John Miller, Christopher Sloop, Thomas Pongetti, Preeti Rao, Clare Wong, Francesca M. Hopkins, Vineet Yadav, Ray F. Weiss, Riley M. Duren, and Charles E. Miller
Atmos. Chem. Phys., 17, 8313–8341,Short summary
We present the first carbon dioxide (CO2) and methane (CH4) measurements from an extensive surface network as part of the Los Angeles Megacity Carbon Project. We describe methods that are essential for understanding carbon fluxes from complex urban environments. CO2 and CH4 levels are spatially and temporally variable, with urban sites showing significant enhancements relative to background. In 2015, the median afternoon enhancement near downtown Los Angeles was ~15 ppm CO2 and ~80 ppb CH4.
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.
Olivier Membrive, Cyril Crevoisier, Colm Sweeney, François Danis, Albert Hertzog, Andreas Engel, Harald Bönisch, and Laurence Picon
Atmos. Meas. Tech., 10, 2163–2181,Short summary
A new high-resolution AirCore system is presented. This system flown with stratospheric balloons allows us to sample atmospheric air during the descent. The analysis of trace gases (CO2 and CH4 in this case) in the collected air sample provides information on the vertical distribution along the atmospheric column. The continuous vertical profiles retrieved may contribute to several research topics concerning the observation of greenhouse gases and, more generally, carbon cycle studies.
Alina Fiehn, Birgit Quack, Helmke Hepach, Steffen Fuhlbrügge, Susann Tegtmeier, Matthew Toohey, Elliot Atlas, and Kirstin Krüger
Atmos. Chem. Phys., 17, 6723–6741,Short summary
Halogenated very short-lived substances (VSLSs) are naturally produced in the ocean and emitted to the atmosphere. In the stratosphere, these compounds can have a significant influence on the ozone layer and climate. During a research cruise in the west Indian Ocean, we found an important source region of halogenated VSLSs during the Asian summer monsoon. Modeling the transport from the ocean to the stratosphere we found two main pathways, one over the Indian Ocean and one over northern India.
John C. Lin, Derek V. Mallia, Dien Wu, and Britton B. Stephens
Atmos. Chem. Phys., 17, 5561–5581,Short summary
Mountainous areas can potentially serve as regions where the key greenhouse gas, carbon dioxide (CO2), can be absorbed from the atmosphere by vegetation, through photosynthesis. Variations in atmospheric CO2 can be used to understand the amount of biospheric fluxes in general. However, CO2 measured in mountains can be difficult to interpret due to the impact from complex atmospheric flows. We show how mountaintop CO2 data can be interpreted by carrying out a series of atmospheric simulations.
Susan S. Kulawik, Chris O'Dell, Vivienne H. Payne, Le Kuai, Helen M. Worden, Sebastien C. Biraud, Colm Sweeney, Britton Stephens, Laura T. Iraci, Emma L. Yates, and Tomoaki Tanaka
Atmos. Chem. Phys., 17, 5407–5438,Short summary
We introduce new vertically resolved GOSAT products that better separate locally and remotely influenced CO2. Current GOSAT column results for CO2 (XCO2) are sensitive to fluxes on continental scales, whereas flux estimates from surface and tower measurements are affected by sampling bias and model transport uncertainty. These new GOSAT measurements of boundary layer CO2 are validated against aircraft and surface observations of CO2 and are compared to vertically resolved MOPITT CO.
Enno Peters, Gaia Pinardi, André Seyler, Andreas Richter, Folkard Wittrock, Tim Bösch, Michel Van Roozendael, François Hendrick, Theano Drosoglou, Alkiviadis F. Bais, Yugo Kanaya, Xiaoyi Zhao, Kimberly Strong, Johannes Lampel, Rainer Volkamer, Theodore Koenig, Ivan Ortega, Olga Puentedura, Mónica Navarro-Comas, Laura Gómez, Margarita Yela González, Ankie Piters, Julia Remmers, Yang Wang, Thomas Wagner, Shanshan Wang, Alfonso Saiz-Lopez, David García-Nieto, Carlos A. Cuevas, Nuria Benavent, Richard Querel, Paul Johnston, Oleg Postylyakov, Alexander Borovski, Alexander Elokhov, Ilya Bruchkouski, Haoran Liu, Cheng Liu, Qianqian Hong, Claudia Rivera, Michel Grutter, Wolfgang Stremme, M. Fahim Khokhar, Junaid Khayyam, and John P. Burrows
Atmos. Meas. Tech., 10, 955–978,Short summary
This work is about harmonization of differential optical absorption spectroscopy retrieval codes, which is a remote sensing technique widely used to derive atmospheric trace gas amounts. The study is based on ground-based measurements performed during the Multi-Axis DOAS Comparison campaign for Aerosols and Trace gases (MAD-CAT) in Mainz, Germany, in summer 2013. In total, 17 international groups working in the field of the DOAS technique participated in this study.
Paul Vallelonga, Niccolo Maffezzoli, Andrew D. Moy, Mark A. J. Curran, Tessa R. Vance, Ross Edwards, Gwyn Hughes, Emily Barker, Gunnar Spreen, Alfonso Saiz-Lopez, J. Pablo Corella, Carlos A. Cuevas, and Andrea Spolaor
Clim. Past, 13, 171–184,Short summary
We present a study of bromine, iodine and sodium in an ice core from Law Dome, in coastal East Antarctica. We find that bromine and iodine variability at Law Dome is correlated to changes in the area of sea ice along the Law Dome coast as observed by satellite since the early 1970s. These findings are in agreement with a previous study based on MSA and confirm a long-term trend of sea ice decrease for this sector of Antarctica over the 20th century.
Nga Lee Ng, Steven S. Brown, Alexander T. Archibald, Elliot Atlas, Ronald C. Cohen, John N. Crowley, Douglas A. Day, Neil M. Donahue, Juliane L. Fry, Hendrik Fuchs, Robert J. Griffin, Marcelo I. Guzman, Hartmut Herrmann, Alma Hodzic, Yoshiteru Iinuma, José L. Jimenez, Astrid Kiendler-Scharr, Ben H. Lee, Deborah J. Luecken, Jingqiu Mao, Robert McLaren, Anke Mutzel, Hans D. Osthoff, Bin Ouyang, Benedicte Picquet-Varrault, Ulrich Platt, Havala O. T. Pye, Yinon Rudich, Rebecca H. Schwantes, Manabu Shiraiwa, Jochen Stutz, Joel A. Thornton, Andreas Tilgner, Brent J. Williams, and Rahul A. Zaveri
Atmos. Chem. Phys., 17, 2103–2162,Short summary
Oxidation of biogenic volatile organic compounds by NO3 is an important interaction between anthropogenic and natural emissions. This review results from a June 2015 workshop and includes the recent literature on kinetics, mechanisms, organic aerosol yields, and heterogeneous chemistry; advances in analytical instrumentation; the current state NO3-BVOC chemistry in atmospheric models; and critical needs for future research in modeling, field observations, and laboratory studies.
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.
Brian M. Lerner, Jessica B. Gilman, Kenneth C. Aikin, Elliot L. Atlas, Paul D. Goldan, Martin Graus, Roger Hendershot, Gabriel A. Isaacman-VanWertz, Abigail Koss, William C. Kuster, Richard A. Lueb, Richard J. McLaughlin, Jeff Peischl, Donna Sueper, Thomas B. Ryerson, Travis W. Tokarek, Carsten Warneke, Bin Yuan, and Joost A. de Gouw
Atmos. Meas. Tech., 10, 291–313,Short summary
Whole air sampling followed by analysis by gas chromatography is a common technique for characterization of trace volatile organic compounds in the atmosphere. We describe a new automated gas chromatograph–mass spectrograph which uses a Stirling cooler for sample preconcentration at −165 °C without the need for a cryogen such as liquid nitrogen. We also discuss potential sources of artifacts from our electropolished stainless steel sampling system and present results from two field campaigns.
Bodo Werner, Jochen Stutz, Max Spolaor, Lisa Scalone, Rasmus Raecke, James Festa, Santo Fedele Colosimo, Ross Cheung, Catalina Tsai, Ryan Hossaini, Martyn P. Chipperfield, Giorgio S. Taverna, Wuhu Feng, James W. Elkins, David W. Fahey, Ru-Shan Gao, Erik J. Hintsa, Troy D. Thornberry, Free Lee Moore, Maria A. Navarro, Elliot Atlas, Bruce C. Daube, Jasna Pittman, Steve Wofsy, and Klaus Pfeilsticker
Atmos. Chem. Phys., 17, 1161–1186,Short summary
The paper reports on inorganic and organic bromine measured in the tropical tropopause layer (TTL) over the eastern Pacific in early 2013. Bryinorg is found to increase from a mean of 2.63 ± 1.04 ppt for θ in the range of 350–360 K to 5.11 ± 1.57 ppt for θ=390 ± 400 K, whereas in the subtropical lower stratosphere, it reaches 7.66 ± 2.95 ppt for θ in the range of 390–400 K. Within the TTL, total bromine is found to range from 20.3 ppt to 22.3 ppt.
Sinikka T. Lennartz, Christa A. Marandino, Marc von Hobe, Pau Cortes, Birgit Quack, Rafel Simo, Dennis Booge, Andrea Pozzer, Tobias Steinhoff, Damian L. Arevalo-Martinez, Corinna Kloss, Astrid Bracher, Rüdiger Röttgers, Elliot Atlas, and Kirstin Krüger
Atmos. Chem. Phys., 17, 385–402,Short summary
We present new sea surface and marine boundary layer measurements of carbonyl sulfide, the most abundant sulfur gas in the atmosphere, and calculate an oceanic emission estimate. Our results imply that oceanic emissions are very unlikely to account for the missing source in the atmospheric budget that is currently discussed for OCS.
Kay Steinkamp, Sara E. Mikaloff Fletcher, Gordon Brailsford, Dan Smale, Stuart Moore, Elizabeth D. Keller, W. Troy Baisden, Hitoshi Mukai, and Britton B. Stephens
Atmos. Chem. Phys., 17, 47–76,Short summary
The exchange of carbon dioxide between the land biosphere in New Zealand and the atmosphere is estimated by combining measurements of the concentration of the gas in the air with model simulations of atmospheric circulation. The results indicate that over the study period of 2011–2013, New Zealand is a larger net sink for CO2 than estimated in the National Inventory Report. Regions in the western South Island, especially those covered predominantly by forests, contribute the most to this signal.