Articles | Volume 23, issue 9
https://doi.org/10.5194/acp-23-5149-2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Special issue:
https://doi.org/10.5194/acp-23-5149-2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Opinion
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05 May 2023
Opinion | Highlight paper |
| 05 May 2023
Opinion: The scientific and community-building roles of the Geoengineering Model Intercomparison Project (GeoMIP) – past, present, and future
Daniele Visioni
CORRESPONDING AUTHOR
Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY, USA
Ben Kravitz
Department of Earth and Atmospheric Science, Indiana University, Bloomington, IN, USA
Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, WA, USA
Alan Robock
Department of Environmental Sciences, Rutgers University, New Brunswick, NJ, USA
Simone Tilmes
National Center for Atmospheric Research, Boulder, CO, USA
Jim Haywood
Met Office Hadley Centre, Exeter, UK
College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, UK
Olivier Boucher
Institut Pierre-Simon Laplace, Sorbonne Université/CNRS, Paris, France
Mark Lawrence
Institute for Advanced Sustainability Studies (IASS), Berliner Str. 130, 14467 Potsdam, Germany
Institute of Environmental Sciences and Geography, University of Potsdam, Potsdam, Germany
Peter Irvine
Earth Sciences, University College London, London, UK
Ulrike Niemeier
Max Planck Institute for Meteorology, Hamburg, Germany
Department of Environmental Sciences, Rutgers University, New Brunswick, NJ, USA
Gabriel Chiodo
Institute for Atmospheric and Climate Science, ETH Zürich, Zurich, Switzerland
Chris Lennard
Climate System Analysis Group, University of Cape Town, Cape Town, South Africa
Shingo Watanabe
Japan Agency for Marine-Earth Science and Technology, Natsushimacho, Yokosuka, Kanagawa, Japan
John C. Moore
College of Global Change and Earth System Science, Beijing Normal University, Beijing, China
CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing, China
Arctic Centre, University of Lapland, Rovaniemi, 96101, Finland
Helene Muri
Department of Energy and Process Engineering, Industrial Ecology Programme, Norwegian University of Science and Technology, Trondheim, Norway
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Christina V. Brodowsky, Timofei Sukhodolov, Gabriel Chiodo, Valentina Aquila, Slimane Bekki, Sandip S. Dhomse, Anton Laakso, Graham W. Mann, Ulrike Niemeier, Ilaria Quaglia, Eugene Rozanov, Anja Schmidt, Takashi Sekiya, Simone Tilmes, Claudia Timmreck, Sandro Vattioni, Daniele Visioni, Pengfei Yu, Yunqian Zhu, and Thomas Peter
EGUsphere, https://doi.org/10.5194/egusphere-2023-1655, https://doi.org/10.5194/egusphere-2023-1655, 2023
This preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).
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The aerosol layer is an essential part of the climate system. We characterize the sulfur budget in a volcanically quiescent (background) setting, with a special focus on the sulfate aerosol layer, for the first time using a multi-model approach. The aim is to identify weak points in the representation of the atmospheric sulfur budget in an intercomparison of nine state-of-the-art coupled global circulation models.
Matthew Henry, Jim Haywood, Andy Jones, Mohit Dalvi, Alice Wells, Daniele Visioni, Ewa Bednarz, Douglas MacMartin, Walker Lee, and Mari Tye
EGUsphere, https://doi.org/10.5194/egusphere-2023-980, https://doi.org/10.5194/egusphere-2023-980, 2023
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Solar climate interventions, such as injecting sulphur in the stratosphere, may be used to offset some of the adverse impacts of global warming. We use two independently developed Earth System Models to assess the uncertainties around stratospheric sulphur injections. The injection locations and amounts are optimized to maintain the same pattern of surface temperature. While both models show reduced warming, the change in rainfall patterns (even without sulfur injections) is uncertain.
Ewa M. Bednarz, Amy H. Butler, Daniele Visioni, Yan Zhang, Ben Kravitz, and Douglas G. MacMartin
EGUsphere, https://doi.org/10.5194/egusphere-2023-495, https://doi.org/10.5194/egusphere-2023-495, 2023
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We use a state-of-the-art earth system model and a set of stratospheric aerosol injection strategies achieving the same level of global mean surface cooling through different combinations of location and/or timing of the injection. We demonstrate that the choice of SAI strategy can lead to contrasting impacts on stratospheric and tropospheric temperatures, circulation and chemistry (including stratospheric ozone), thereby leading to different impacts on regional surface climate.
Yan Zhang, Douglas G. MacMartin, Daniele Visioni, Ewa Bednarz, and Ben Kravitz
EGUsphere, https://doi.org/10.5194/egusphere-2023-117, https://doi.org/10.5194/egusphere-2023-117, 2023
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Injecting SO2 into the lower stratosphere can temporarily reduce the global mean temperature and mitigate some of the risks associated with climate change, but injecting at different latitudes and seasons would have different impacts. This study introduces a comprehensive set of SAI strategies and systematically explores the importance of the choice of SAI strategy, demonstrating that it notably affects the distribution of aerosol cloud, injection efficiency, and various surface climate impacts.
Ilaria Quaglia, Claudia Timmreck, Ulrike Niemeier, Daniele Visioni, Giovanni Pitari, Christina Brodowsky, Christoph Brühl, Sandip S. Dhomse, Henning Franke, Anton Laakso, Graham W. Mann, Eugene Rozanov, and Timofei Sukhodolov
Atmos. Chem. Phys., 23, 921–948, https://doi.org/10.5194/acp-23-921-2023, https://doi.org/10.5194/acp-23-921-2023, 2023
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The last very large explosive volcanic eruption we have measurements for is the eruption of Mt. Pinatubo in 1991. It is therefore often used as a benchmark for climate models' ability to reproduce these kinds of events. Here, we compare available measurements with the results from multiple experiments conducted with climate models interactively simulating the aerosol cloud formation.
Daniele Visioni, Ewa M. Bednarz, Walker R. Lee, Ben Kravitz, Andy Jones, Jim M. Haywood, and Douglas G. MacMartin
Atmos. Chem. Phys., 23, 663–685, https://doi.org/10.5194/acp-23-663-2023, https://doi.org/10.5194/acp-23-663-2023, 2023
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The paper constitutes Part 1 of a study performing a first systematic inter-model comparison of the atmospheric responses to stratospheric sulfate aerosol injections (SAIs) at various latitudes as simulated by three state-of-the-art Earth system models. We identify similarities and differences in the modeled aerosol burden, investigate the differences in the aerosol approaches between the models, and ultimately show the differences produced in surface climate, temperature and precipitation.
Ewa M. Bednarz, Daniele Visioni, Ben Kravitz, Andy Jones, James M. Haywood, Jadwiga Richter, Douglas G. MacMartin, and Peter Braesicke
Atmos. Chem. Phys., 23, 687–709, https://doi.org/10.5194/acp-23-687-2023, https://doi.org/10.5194/acp-23-687-2023, 2023
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Building on Part 1 of this two-part study, we demonstrate the role of biases in climatological circulation and specific aspects of model microphysics in driving the differences in simulated sulfate distributions amongst three Earth system models. We then characterize the simulated changes in stratospheric and free-tropospheric temperatures, ozone, water vapor, and large-scale circulation, elucidating the role of the above aspects in the surface responses discussed in Part 1.
Jadwiga H. Richter, Daniele Visioni, Douglas G. MacMartin, David A. Bailey, Nan Rosenbloom, Brian Dobbins, Walker R. Lee, Mari Tye, and Jean-Francois Lamarque
Geosci. Model Dev., 15, 8221–8243, https://doi.org/10.5194/gmd-15-8221-2022, https://doi.org/10.5194/gmd-15-8221-2022, 2022
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Solar climate intervention using stratospheric aerosol injection is a proposed method of reducing global mean temperatures to reduce the worst consequences of climate change. We present a new modeling protocol aimed at simulating a plausible deployment of stratospheric aerosol injection and reproducibility of simulations using other Earth system models: Assessing Responses and Impacts of Solar climate intervention on the Earth system with stratospheric aerosol injection (ARISE-SAI).
Mari R. Tye, Katherine Dagon, Maria J. Molina, Jadwiga H. Richter, Daniele Visioni, Ben Kravitz, and Simone Tilmes
Earth Syst. Dynam., 13, 1233–1257, https://doi.org/10.5194/esd-13-1233-2022, https://doi.org/10.5194/esd-13-1233-2022, 2022
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We examined the potential effect of stratospheric aerosol injection (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 the largest decreases in summer. In contrast, nighttime warming may be greatest at high latitudes in winter. SAI may reduce the frequency and intensity of extreme rainfall. The combined changes may exacerbate drying over parts of the global south.
Ilaria Quaglia, Daniele Visioni, Giovanni Pitari, and Ben Kravitz
Atmos. Chem. Phys., 22, 5757–5773, https://doi.org/10.5194/acp-22-5757-2022, https://doi.org/10.5194/acp-22-5757-2022, 2022
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Carbonyl sulfide is a gas that mixes very well in the atmosphere and can reach the stratosphere, where it reacts with sunlight and produces aerosol. Here we propose that, by increasing surface fluxes by an order of magnitude, the number of stratospheric aerosols produced may be enough to partially offset the warming produced by greenhouse gases. We explore what effect this would have on the atmospheric composition.
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, https://doi.org/10.5194/acp-22-4557-2022, https://doi.org/10.5194/acp-22-4557-2022, 2022
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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.
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, https://doi.org/10.5194/acp-22-2999-2022, https://doi.org/10.5194/acp-22-2999-2022, 2022
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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.
Debra K. Weisenstein, Daniele Visioni, Henning Franke, Ulrike Niemeier, Sandro Vattioni, Gabriel Chiodo, Thomas Peter, and David W. Keith
Atmos. Chem. Phys., 22, 2955–2973, https://doi.org/10.5194/acp-22-2955-2022, https://doi.org/10.5194/acp-22-2955-2022, 2022
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This paper explores a potential method of geoengineering that could be used to slow the rate of change of climate over decadal scales. We use three climate models to explore how injections of accumulation-mode sulfuric acid aerosol change the large-scale stratospheric particle size distribution and radiative forcing response for the chosen scenarios. Radiative forcing per unit sulfur injected and relative to the change in aerosol burden is larger with particulate than with SO2 injections.
Daniele Visioni, Simone Tilmes, Charles Bardeen, Michael Mills, Douglas G. MacMartin, Ben Kravitz, and Jadwiga H. Richter
Atmos. Chem. Phys., 22, 1739–1756, https://doi.org/10.5194/acp-22-1739-2022, https://doi.org/10.5194/acp-22-1739-2022, 2022
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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.
Yan Zhang, Douglas G. MacMartin, Daniele Visioni, and Ben Kravitz
Earth Syst. Dynam., 13, 201–217, https://doi.org/10.5194/esd-13-201-2022, https://doi.org/10.5194/esd-13-201-2022, 2022
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Adding SO2 to the stratosphere could temporarily cool the planet by reflecting more sunlight back to space. However, adding SO2 at different latitude(s) and season(s) leads to significant differences in regional surface climate. This study shows that, to cool the planet by 1–1.5 °C, there are likely six to eight choices of injection latitude(s) and season(s) that lead to meaningfully different distributions of climate impacts.
Anton Laakso, Ulrike Niemeier, Daniele Visioni, Simone Tilmes, and Harri Kokkola
Atmos. Chem. Phys., 22, 93–118, https://doi.org/10.5194/acp-22-93-2022, https://doi.org/10.5194/acp-22-93-2022, 2022
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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.
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, https://doi.org/10.5194/acp-21-10039-2021, https://doi.org/10.5194/acp-21-10039-2021, 2021
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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.
Henning Franke, Ulrike Niemeier, and Daniele Visioni
Atmos. Chem. Phys., 21, 8615–8635, https://doi.org/10.5194/acp-21-8615-2021, https://doi.org/10.5194/acp-21-8615-2021, 2021
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Stratospheric aerosol modification (SAM) can alter the quasi-biennial oscillation (QBO). Our simulations with two different models show that the characteristics of the QBO response are primarily determined by the meridional structure of the aerosol-induced heating. Therefore, the QBO response to SAM depends primarily on the location of injection, while injection type and rate act to scale the specific response. Our results have important implications for evaluating adverse side effects of SAM.
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, https://doi.org/10.5194/acp-21-4231-2021, https://doi.org/10.5194/acp-21-4231-2021, 2021
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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.
Walker Lee, Douglas MacMartin, Daniele Visioni, and Ben Kravitz
Earth Syst. Dynam., 11, 1051–1072, https://doi.org/10.5194/esd-11-1051-2020, https://doi.org/10.5194/esd-11-1051-2020, 2020
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The injection of aerosols into the stratosphere to reflect sunlight could reduce global warming, but this type of
geoengineeringwould also impact other variables like precipitation and sea ice. In this study, we model various climate impacts of geoengineering on a 3-D graph to show how trying to meet one climate goal will affect other variables. We also present two computer simulations which validate our model and show that geoengineering could regulate precipitation as well as temperature.
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., https://doi.org/10.5194/acp-2020-525, https://doi.org/10.5194/acp-2020-525, 2020
Preprint withdrawn
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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.
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, https://doi.org/10.5194/acp-19-11559-2019, https://doi.org/10.5194/acp-19-11559-2019, 2019
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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.
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, https://doi.org/10.5194/acp-19-10087-2019, https://doi.org/10.5194/acp-19-10087-2019, 2019
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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.
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, https://doi.org/10.5194/acp-19-921-2019, https://doi.org/10.5194/acp-19-921-2019, 2019
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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.
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, https://doi.org/10.5194/acp-18-16155-2018, https://doi.org/10.5194/acp-18-16155-2018, 2018
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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.
Daniele Visioni, Giovanni Pitari, Glauco di Genova, Simone Tilmes, and Irene Cionni
Atmos. Chem. Phys., 18, 14867–14887, https://doi.org/10.5194/acp-18-14867-2018, https://doi.org/10.5194/acp-18-14867-2018, 2018
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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.
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, https://doi.org/10.5194/acp-18-8409-2018, https://doi.org/10.5194/acp-18-8409-2018, 2018
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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.
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, https://doi.org/10.5194/acp-18-7217-2018, https://doi.org/10.5194/acp-18-7217-2018, 2018
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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.
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, https://doi.org/10.5194/acp-18-6699-2018, https://doi.org/10.5194/acp-18-6699-2018, 2018
Daniele Visioni, Giovanni Pitari, Paolo Tuccella, and Gabriele Curci
Atmos. Chem. Phys., 18, 2787–2808, https://doi.org/10.5194/acp-18-2787-2018, https://doi.org/10.5194/acp-18-2787-2018, 2018
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Sulfate geoengineering is a proposed technique that would mimic explosive volcanic eruptions by injecting sulfur dioxide (SO2) into the stratosphere to counteract global warming produced by greenhouse gases by reflecting part of the incoming solar radiation. In this study we use two models to simulate how the injected aerosols would react to dynamical changes in the stratosphere (due to the quasi-biennial oscillation - QBO) and how this would affect the deposition of sulfate at the surface.
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, https://doi.org/10.5194/acp-18-1091-2018, https://doi.org/10.5194/acp-18-1091-2018, 2018
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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.
Daniele Visioni, Giovanni Pitari, Valentina Aquila, Simone Tilmes, Irene Cionni, Glauco Di Genova, and Eva Mancini
Atmos. Chem. Phys., 17, 11209–11226, https://doi.org/10.5194/acp-17-11209-2017, https://doi.org/10.5194/acp-17-11209-2017, 2017
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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.
Daniele Visioni, Giovanni Pitari, and Valentina Aquila
Atmos. Chem. Phys., 17, 3879–3889, https://doi.org/10.5194/acp-17-3879-2017, https://doi.org/10.5194/acp-17-3879-2017, 2017
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This review paper summarizes the state-of-the-art knowledge of the direct and indirect side effects of sulfate geoengineering, that is, the injection of sulfur dioxide into the stratosphere in order to offset the warming caused by the anthropic increase in greenhouse gasses. An overview of the various effects and their uncertainties, using results from published scientific articles, may help fine-tune the best amount of sulfate to be injected in an eventual realization of the experiment.
Seyed Vahid Mousavi, Khalil Karami, Simone Tilmes, Helene Muri, Lili Xia, and Abolfazl Rezaei
Atmos. Chem. Phys., 23, 10677–10695, https://doi.org/10.5194/acp-23-10677-2023, https://doi.org/10.5194/acp-23-10677-2023, 2023
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Understanding atmospheric dust changes in the Middle East and North Africa (MENA) region under future climate scenarios is essential. By injecting sulfate aerosols into the stratosphere, stratospheric aerosol injection (SAI) geoengineering reflects some of the incoming sunlight back to space. This study shows that the MENA region would experience lower dust concentration under both SAI and RCP8.5 scenarios compared to the current climate (CTL) by the end of the century.
Jun Wang, John C. Moore, and Liyun Zhao
Earth Syst. Dynam., 14, 989–1013, https://doi.org/10.5194/esd-14-989-2023, https://doi.org/10.5194/esd-14-989-2023, 2023
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Apparent temperatures and PM2.5 pollution depend on humidity and wind speed in addition to surface temperature and impact human health and comfort. Apparent temperatures will reach dangerous levels more commonly in the future because of water vapor pressure rises and lower expected wind speeds, but these will also drive changes in PM2.5. Solar geoengineering can significantly reduce the frequency of extreme events relative to modest and especially
business-as-usualgreenhouse scenarios.
Gabriel Chiodo, Marina Friedel, Svenja Seeber, Daniela Domeisen, Andrea Stenke, Timofei Sukhodolov, and Franziska Zilker
Atmos. Chem. Phys., 23, 10451–10472, https://doi.org/10.5194/acp-23-10451-2023, https://doi.org/10.5194/acp-23-10451-2023, 2023
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Stratospheric ozone protects the biosphere from harmful UV radiation. Anthropogenic activity has led to a reduction in the ozone layer in the recent past, but thanks to the implementation of the Montreal Protocol, the ozone layer is projected to recover. In this study, we show that projected future changes in Arctic ozone abundances during springtime will influence stratospheric climate and thereby actively modulate large-scale circulation changes in the Northern Hemisphere.
Marina Friedel, Gabriel Chiodo, Timofei Sukhodolov, James Keeble, Thomas Peter, Svenja Seeber, Andrea Stenke, Hideharu Akiyoshi, Eugene Rozanov, David Plummer, Patrick Jöckel, Guang Zeng, Olaf Morgenstern, and Béatrice Josse
Atmos. Chem. Phys., 23, 10235–10254, https://doi.org/10.5194/acp-23-10235-2023, https://doi.org/10.5194/acp-23-10235-2023, 2023
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Previously, it has been suggested that springtime Arctic ozone depletion might worsen in the coming decades due to climate change, which might counteract the effect of reduced ozone-depleting substances. Here, we show with different chemistry–climate models that springtime Arctic ozone depletion will likely decrease in the future. Further, we explain why models show a large spread in the projected development of Arctic ozone depletion and use the model spread to constrain future projections.
Sandro Vattioni, Andrea Stenke, Beiping Luo, Gabriel Chiodo, Timofei Sukhodolov, Elia Wunderlin, and Thomas Peter
EGUsphere, https://doi.org/10.5194/egusphere-2023-1726, https://doi.org/10.5194/egusphere-2023-1726, 2023
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We investigate the sensitivity of aerosol size distributions in the presence of strong SO2 injections for climate intervention or after volcanic eruptions to the call sequence and frequency of the routines for nucleation and condensation in sectional aerosol models with operator splitting. Using the aerosol chemistry-climate model SOCOL-AERvs2, we show that the radiative and chemical output is sensitive to these settings at high H2SO4 supersaturations, and how to obtain reliable results.
Malte Meinshausen, Carl-Friedrich Schleussner, Kathleen Beyer, Greg Bodeker, Olivier Boucher, Josep G. Canadell, John S. Daniel, Aïda Diongue-Niang, Fatimah Driouech, Erich Fischer, Piers Forster, Michael Grose, Gerrit Hansen, Zeke Hausfather, Tatiana Ilyina, Jarmo S. Kikstra, Joyce Kimutai, Andrew King, June-Yi Lee, Chris Lennard, Tabea Lissner, Alexander Nauels, Glen P. Peters, Anna Pirani, Gian-Kasper Plattner, Hans Pörtner, Joeri Rogelj, Maisa Rojas, Joyashree Roy, Bjørn H. Samset, Benjamin M. Sanderson, Roland Séférian, Sonia Seneviratne, Christopher J. Smith, Sophie Szopa, Adelle Thomas, Diana Urge-Vorsatz, Guus J. M. Velders, Tokuta Yokohata, Tilo Ziehn, and Zebedee Nicholls
Geosci. Model Dev. Discuss., https://doi.org/10.5194/gmd-2023-176, https://doi.org/10.5194/gmd-2023-176, 2023
Preprint under review for GMD
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For the next generation of Earth System Model runs to project future climate change, the scientific community considers new scenarios to succeed RCPs and SSPs. As a contribution to that debate, we reflect on relevant policy and scientific research questions and suggest categories for Representative Emission Pathways (REP). These categories are tailored to the Paris Agreement long-term temperature goal, high-risk outcomes in the absence of further climate policy and worlds “that could have been”.
Felix Wrana, Ulrike Niemeier, Larry W. Thomason, Sandra Wallis, and Christian von Savigny
Atmos. Chem. Phys., 23, 9725–9743, https://doi.org/10.5194/acp-23-9725-2023, https://doi.org/10.5194/acp-23-9725-2023, 2023
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The stratospheric aerosol layer is a naturally occurring and permanent layer of aerosol, in this case very small droplets of mostly sulfuric acid and water, that has a cooling effect on our climate. To quantify this effect and for our general understanding of stratospheric microphysical processes, knowledge of the size of those aerosol particles is needed. Using satellite measurements and atmospheric models we show that some volcanic eruptions can lead to on average smaller aerosol sizes.
Christina V. Brodowsky, Timofei Sukhodolov, Gabriel Chiodo, Valentina Aquila, Slimane Bekki, Sandip S. Dhomse, Anton Laakso, Graham W. Mann, Ulrike Niemeier, Ilaria Quaglia, Eugene Rozanov, Anja Schmidt, Takashi Sekiya, Simone Tilmes, Claudia Timmreck, Sandro Vattioni, Daniele Visioni, Pengfei Yu, Yunqian Zhu, and Thomas Peter
EGUsphere, https://doi.org/10.5194/egusphere-2023-1655, https://doi.org/10.5194/egusphere-2023-1655, 2023
This preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).
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The aerosol layer is an essential part of the climate system. We characterize the sulfur budget in a volcanically quiescent (background) setting, with a special focus on the sulfate aerosol layer, for the first time using a multi-model approach. The aim is to identify weak points in the representation of the atmospheric sulfur budget in an intercomparison of nine state-of-the-art coupled global circulation models.
Hauke Schmidt, Sebastian Rast, Jiawei Bao, Shih-Wei Fang, Diego Jimenez-de la Cuesta, Paul Keil, Lukas Kluft, Clarissa Kroll, Theresa Lang, Ulrike Niemeier, Andrea Schneidereit, Andrew I. L. Williams, and Bjorn Stevens
EGUsphere, https://doi.org/10.5194/egusphere-2023-1575, https://doi.org/10.5194/egusphere-2023-1575, 2023
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A recent development in numerical models of the global atmosphere is the increase of horizontal resolution from the order of hundred to a few kilometers grid spacing. However, the vertical grid spacing of these models has not been reduced at the same rate as the horizontal grid spacing. Here we assess effects of much finer vertical grid spacings in particular on cloud quantities and the atmospheric energy balance.
Abolfazl Rezaei, Khalil Karami, Simone Tilmes, and John C. Moore
EGUsphere, https://doi.org/10.5194/egusphere-2023-1654, https://doi.org/10.5194/egusphere-2023-1654, 2023
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Water storage (WS) plays a profound role in the lives of people in the Middle East and North Africa and Mediterranean climate “hot spots”. Simulated is WS changed by greenhouse gas (GHG) warming with and without stratospheric aerosol intervention (SAI). WS significantly increases in the Arabian Peninsula and decreases around Mediterranean under GHG. While SAI partially ameliorates the GHG impacts, Projected WS increases in dry regions and decreases in wet areas relative to the present climate.
Chenwei Fang, Jim M. Haywood, Ju Liang, Ben T. Johnson, Ying Chen, and Bin Zhu
Atmos. Chem. Phys., 23, 8341–8368, https://doi.org/10.5194/acp-23-8341-2023, https://doi.org/10.5194/acp-23-8341-2023, 2023
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The responses of Asian summer monsoon duration and intensity to air pollution mitigation are identified given the net-zero future. We show that reducing scattering aerosols makes the rainy season longer and stronger across South Asia and East Asia but that absorbing aerosol reduction has the opposite effect. Our results hint at distinct monsoon responses to emission controls that target different aerosols.
James Matthew Haywood, Andy Jones, Anthony Crawford Jones, and Philip J. Rasch
EGUsphere, https://doi.org/10.5194/egusphere-2023-1611, https://doi.org/10.5194/egusphere-2023-1611, 2023
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The difficulties in ameliorating global warming and the associated climate change via conventional mitigation are well documented, with all climate model scenarios exceeding 1.5 °C above the preindustrial level in the near-future. There is therefore a growing interest in ‘geoengineering’ to reflect a greater proportion of sunlight back to space and offset some of the global warming. We use a state-of-the-art Earth System model to investigate two of the most prominent geoengineering strategies.
Duseong S. Jo, Simone Tilmes, Louisa K. Emmons, Siyuan Wang, and Francis Vitt
Geosci. Model Dev., 16, 3893–3906, https://doi.org/10.5194/gmd-16-3893-2023, https://doi.org/10.5194/gmd-16-3893-2023, 2023
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A new simple secondary organic aerosol (SOA) scheme has been developed for the Community Atmosphere Model (CAM) based on the complex SOA scheme in CAM with detailed chemistry (CAM-chem). The CAM with the new SOA scheme shows better agreements with CAM-chem in terms of aerosol concentrations and radiative fluxes, which ensures more consistent results between different compsets in the Community Earth System Model. The new SOA scheme also has technical advantages for future developments.
Yunqian Zhu, Robert W. Portmann, Douglas Kinnison, Owen B. Toon, Luis Millán, Jun Zhang, Holger Vömel, Simone Tilmes, Charles G. Bardeen, Xinyue Wang, Stephanie Evan, William J. Randel, and Karen H. Rosenlof
EGUsphere, https://doi.org/10.5194/egusphere-2023-1334, https://doi.org/10.5194/egusphere-2023-1334, 2023
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The 2022 Hunga Tonga eruption injected a large amount of water into the stratosphere. Ozone depletion was observed inside the volcanic plume. Chlorine and water vapor injected by this eruption exceeded the normal range, which made the ozone chemistry during this event occur at a higher temperature than polar ozone depletion. Unlike polar ozone chemistry where chlorine nitrate is more important, hypochlorous acid plays a large role in the in-plume chlorine balance and heterogeneous processes.
Alan Robock, Lili Xia, Cheryl S. Harrison, Joshua Coupe, Owen B. Toon, and Charles G. Bardeen
Atmos. Chem. Phys., 23, 6691–6701, https://doi.org/10.5194/acp-23-6691-2023, https://doi.org/10.5194/acp-23-6691-2023, 2023
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A nuclear war could produce a nuclear winter, with catastrophic consequences for global food supplies. Nuclear winter theory helped to end the nuclear arms race in the 1980s, but more than 10 000 nuclear weapons still exist. This means they can be used, by unstable leaders, accidently from technical malfunctions or human error, or by terrorists. Therefore, it is urgent for scientists to study these issues, broadly communicate their results, and work for the elimination of nuclear weapons.
Danny M. Leung, Jasper F. Kok, Longlei Li, Natalie M. Mahowald, David M. Lawrence, Simone Tilmes, Erik Kluzek, Martina Klose, and Carlos Pérez García-Pando
EGUsphere, https://doi.org/10.5194/egusphere-2023-823, https://doi.org/10.5194/egusphere-2023-823, 2023
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This study uses a premier Earth system model to evaluate a new desert dust emission scheme proposed in our companion paper. We show that our scheme accounts for more dust emission physics, hence matching better against observations than other existing dust emission schemes do. Our scheme's dust emissions also couple tightly with meteorology, hence likely improving the modeled dust sensitivity to climate change. We believe this work is vital for improving dust representation in climate models.
Calvin Howes, Pablo E. Saide, Hugh Coe, Amie Nicole Dobracki, Steffen Freitag, Jim M. Haywood, Steven G. Howell, Siddhant Gupta, Janek Uin, Mary Kacarab, Chongai Kuang, L. Ruby Leung, Athanasios Nenes, Greg McFarquhar, Jens Redemann, Arther J. Sedlacek, Kenneth L. Thornhill, Jenny P. S. Wong, Robert Wood, Huihui Wu, Yang Zhang, Jianhao Zhang, and Paquita Zuidema
EGUsphere, https://doi.org/10.5194/egusphere-2023-886, https://doi.org/10.5194/egusphere-2023-886, 2023
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To better understand smoke properties and its interactions with clouds, we compare WRF-CAM5 with observations from ORACLES, CLARIFY, and LASIC field campaigns in the Southeastern Atlantic in August 2017. The model transports and mixes smoke well but is not fully capturing some important processes. These include smoke chemical and physical aging over 4–12 days, smoke removal by rain, new particle formation, aerosol activation into cloud droplets, and boundary layer turbulence.
Matthew Henry, Jim Haywood, Andy Jones, Mohit Dalvi, Alice Wells, Daniele Visioni, Ewa Bednarz, Douglas MacMartin, Walker Lee, and Mari Tye
EGUsphere, https://doi.org/10.5194/egusphere-2023-980, https://doi.org/10.5194/egusphere-2023-980, 2023
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Solar climate interventions, such as injecting sulphur in the stratosphere, may be used to offset some of the adverse impacts of global warming. We use two independently developed Earth System Models to assess the uncertainties around stratospheric sulphur injections. The injection locations and amounts are optimized to maintain the same pattern of surface temperature. While both models show reduced warming, the change in rainfall patterns (even without sulfur injections) is uncertain.
Abolfazl Rezaei, Khalil Karami, Simone Tilmes, and John C. Moore
Atmos. Chem. Phys., 23, 5835–5850, https://doi.org/10.5194/acp-23-5835-2023, https://doi.org/10.5194/acp-23-5835-2023, 2023
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Teleconnection patterns are important characteristics of the climate system; well-known examples include the El Niño and La Niña events driven from the tropical Pacific. We examined how spatiotemporal patterns that arise in the Pacific and Atlantic oceans behave under stratospheric aerosol geoengineering and greenhouse gas (GHG)-induced warming. In general, geoengineering reverses trends; however, the changes in decadal oscillation for the AMO, NAO, and PDO imposed by GHG are not suppressed.
Yan Huang, Liyun Zhao, Yiliang Ma, Michael Wolovick, and John C. Moore
The Cryosphere Discuss., https://doi.org/10.5194/tc-2023-58, https://doi.org/10.5194/tc-2023-58, 2023
Revised manuscript under review for TC
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Geothermal heat flux (GHF) is an important factor affecting the basal thermal environment of an ice sheet and crucial for its dynamics. But it is poorly defined for the Antarctic ice sheet. We simulate the basal temperature and basal melting rate with five different GHF datasets. We use specularity content as a two-sided constraint to discriminate between local wet or dry basal conditions. Two medium magnitude GHF distribution maps rank best, showing that most of the inland bed area is frozen.
Wenfu Tang, Simone Tilmes, David M. Lawrence, Fang Li, Cenlin He, Louisa K. Emmons, Rebecca R. Buchholz, and Lili Xia
Atmos. Chem. Phys., 23, 5467–5486, https://doi.org/10.5194/acp-23-5467-2023, https://doi.org/10.5194/acp-23-5467-2023, 2023
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Globally, total wildfire burned area is projected to increase over the 21st century under scenarios without geoengineering and decrease under the two geoengineering scenarios. Geoengineering reduces fire by decreasing surface temperature and wind speed and increasing relative humidity and soil water. However, geoengineering also yields reductions in precipitation, which offset some of the fire reduction.
Jan Polcher, Anthony Schrapffer, Eliott Dupont, Lucia Rinchiuso, Xudong Zhou, Olivier Boucher, Emmanuel Mouche, Catherine Ottlé, and Jérôme Servonnat
Geosci. Model Dev., 16, 2583–2606, https://doi.org/10.5194/gmd-16-2583-2023, https://doi.org/10.5194/gmd-16-2583-2023, 2023
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The proposed graphs of hydrological sub-grid elements for atmospheric models allow us to integrate the topographical elements needed in land surface models for a realistic representation of horizontal water and energy transport. The study demonstrates the numerical properties of the automatically built graphs and the simulated water flows.
Alistair Duffey, Robbie Mallett, Peter J. Irvine, Michel Tsamados, and Julienne Stroeve
EGUsphere, https://doi.org/10.5194/egusphere-2023-810, https://doi.org/10.5194/egusphere-2023-810, 2023
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The Arctic is warming several times faster than the rest of the planet. Here, we use climate model projections to quantify for the first time how this faster warming in the Arctic impacts the timing of crossing the 1.5 °C and 2 °C thresholds defined in the Paris agreement. We show that under plausible emissions scenarios that fail to meet the Paris 1.5 °C target, the faster warming in the Arctic is expected to bring forward the date when that target is breached by around 5 years.
Sam S. Rabin, William J. Sacks, Danica L. Lombardozzi, Lili Xia, and Alan Robock
Geosci. Model Dev. Discuss., https://doi.org/10.5194/gmd-2023-66, https://doi.org/10.5194/gmd-2023-66, 2023
Revised manuscript accepted for GMD
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Climate models can help us simulate how the agricultural system will be affected by and respond to environmental change, but to be trustworthy they must realistically reproduce historical patterns. When farmers plant their crops and what varieties they choose will be important aspects of future adaptation. Here, we improve the crop component of a global model to better simulate observed growing seasons and examine the impacts on simulated crop yields and irrigation demand.
Wenfu Tang, Louisa K. Emmons, Helen M. Worden, Rajesh Kumar, Cenlin He, Benjamin Gaubert, Zhonghua Zheng, Simone Tilmes, Rebecca R. Buchholz, Sara-Eva Martinez-Alonso, Claire Granier, Antonin Soulie, Kathryn McKain, Bruce Daube, Jeff Peischl, Chelsea Thompson, and Pieternel Levelt
Geosci. Model Dev. Discuss., https://doi.org/10.5194/gmd-2023-50, https://doi.org/10.5194/gmd-2023-50, 2023
Revised manuscript accepted for GMD
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The new MUSICAv0 model enables the study of atmospheric chemistry across all relevant scales. We develop a MUSICAv0 grid for Africa. We evaluate MUSICAv0 with observations, and compare it with a previously used model – WRF-Chem. Overall, the performance of MUSICAv0 is comparable to WRF-Chem. Based on model-satellite discrepancies, we find that future field campaigns in an East African region (30° E – 45° E, 5° S – 5° N) could substantially improve the predictive skill of air quality models.
George Jordan, James Haywood, Florent Malavelle, Ying Chen, Amy Peace, Eliza Duncan, Daniel G. Partridge, Paul Kim, Duncan Watson-Parris, Toshihiko Takemura, David Neubauer, Gunnar Myhre, Ragnhild Skeie, and Anton Laakso
EGUsphere, https://doi.org/10.5194/egusphere-2023-619, https://doi.org/10.5194/egusphere-2023-619, 2023
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The 2014−15 Holuhraun eruption caused a huge aerosol plume in an otherwise unpolluted region providing an opportunity to study how aerosol alter cloud properties. This two-part study uses observations and models to quantify this relationship’s impact on the Earth’s energy budget. Part 1 suggests the models capture the observed spatial and chemical evolution of the plume, yet no model plume is exact. Understanding these differences is key for Part 2 where changes to cloud properties are explored.
Simone Tilmes, Michael J. Mills, Yunqian Zhu, Charles G. Bardeen, Francis Vitt, Pengfei Yu, David Fillmore, Xiaohong Liu, Brian Toon, and Terry Deshler
Geosci. Model Dev. Discuss., https://doi.org/10.5194/gmd-2023-79, https://doi.org/10.5194/gmd-2023-79, 2023
Revised manuscript accepted for GMD
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We implemented an alternative aerosol scheme in the high and low-top model versions of the Community Earth System Model Version 2 (CESM2) with a more detailed description of tropospheric and stratospheric aerosol size distributions than the existing aerosol model. The development enables the comparison of different aerosol schemes with different complexity in the same model framework and identifies improvements in comparison to a range of observations in both the troposphere and stratosphere.
Alice F. Wells, Andy Jones, Martin Osborne, Lilly Damany-Pearce, Daniel G. Partridge, and James M. Haywood
Atmos. Chem. Phys., 23, 3985–4007, https://doi.org/10.5194/acp-23-3985-2023, https://doi.org/10.5194/acp-23-3985-2023, 2023
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In 2019 the Raikoke volcano erupted explosively, emitting the largest injection of SO2 into the stratosphere since 2011. Observations indicated that a large amount of volcanic ash was also injected. Previous studies have identified that volcanic ash can prolong the lifetime of stratospheric aerosol optical depth, which we explore in UKESM1. Comparisons to observations suggest that including ash in model emission schemes can improve the representation of volcanic plumes in global climate models.
Khalil Karami, Rolando Garcia, Christoph Jacobi, Jadwiga H. Richter, and Simone Tilmes
Atmos. Chem. Phys., 23, 3799–3818, https://doi.org/10.5194/acp-23-3799-2023, https://doi.org/10.5194/acp-23-3799-2023, 2023
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Alongside mitigation and adaptation efforts, stratospheric aerosol intervention (SAI) is increasingly considered a third pillar to combat dangerous climate change. We investigate the teleconnection between the quasi-biennial oscillation in the equatorial stratosphere and the Arctic stratospheric polar vortex under a warmer climate and an SAI scenario. We show that the Holton–Tan relationship weakens under both scenarios and discuss the physical mechanisms responsible for such changes.
Franziska Zilker, Timofei Sukhodolov, Gabriel Chiodo, Marina Friedel, Tatiana Egorova, Eugene Rozanov, Jan Sedlacek, Svenja Seeber, and Thomas Peter
EGUsphere, https://doi.org/10.5194/egusphere-2023-326, https://doi.org/10.5194/egusphere-2023-326, 2023
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The Montreal Protocol (MP) has successfully reduced the Antarctic ozone hole by banning chlorofluorocarbons (CFCs) that destroy the ozone layer. Moreover, CFCs are strong greenhouse gases (GHGs) that would have strengthened global warming. In this study, we investigate the surface weather and climate in a world without the MP at the end of the 21st century disentangling ozone-mediated and GHG impacts of CFCs. Overall, we avoided 1.9 K global surface warming and a poleward shift of storm tracks.
Ewa M. Bednarz, Amy H. Butler, Daniele Visioni, Yan Zhang, Ben Kravitz, and Douglas G. MacMartin
EGUsphere, https://doi.org/10.5194/egusphere-2023-495, https://doi.org/10.5194/egusphere-2023-495, 2023
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We use a state-of-the-art earth system model and a set of stratospheric aerosol injection strategies achieving the same level of global mean surface cooling through different combinations of location and/or timing of the injection. We demonstrate that the choice of SAI strategy can lead to contrasting impacts on stratospheric and tropospheric temperatures, circulation and chemistry (including stratospheric ozone), thereby leading to different impacts on regional surface climate.
Chencheng Shen, John C. Moore, Heri Kuswanto, and Liyun Zhao
Earth Syst. Dynam. Discuss., https://doi.org/10.5194/esd-2023-6, https://doi.org/10.5194/esd-2023-6, 2023
Revised manuscript under review for ESD
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The Indonesian Throughflow is an important pathway connecting the Pacific and Indian Oceans. Solar dimming and sulfate aerosol injection geoengineering will affect the water volumes transported in future – but so will increasing greenhouse gases. Geoengineering with sulfate aerosols affects winds more than simply “shading the sun” and reduces the water transport more – similar as we simulate for unabated greenhouse gas emissions.
Yan Zhang, Douglas G. MacMartin, Daniele Visioni, Ewa Bednarz, and Ben Kravitz
EGUsphere, https://doi.org/10.5194/egusphere-2023-117, https://doi.org/10.5194/egusphere-2023-117, 2023
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Injecting SO2 into the lower stratosphere can temporarily reduce the global mean temperature and mitigate some of the risks associated with climate change, but injecting at different latitudes and seasons would have different impacts. This study introduces a comprehensive set of SAI strategies and systematically explores the importance of the choice of SAI strategy, demonstrating that it notably affects the distribution of aerosol cloud, injection efficiency, and various surface climate impacts.
Yann Quilcaille, Thomas Gasser, Philippe Ciais, and Olivier Boucher
Geosci. Model Dev., 16, 1129–1161, https://doi.org/10.5194/gmd-16-1129-2023, https://doi.org/10.5194/gmd-16-1129-2023, 2023
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The model OSCAR is a simple climate model, meaning its representation of the Earth system is simplified but calibrated on models of higher complexity. Here, we diagnose its latest version using a total of 99 experiments in a probabilistic framework and under observational constraints. OSCAR v3.1 shows good agreement with observations, complex Earth system models and emerging properties. Some points for improvements are identified, such as the ocean carbon cycle.
Kevin Wolf, Nicolas Bellouin, and Olivier Boucher
EGUsphere, https://doi.org/10.5194/egusphere-2023-155, https://doi.org/10.5194/egusphere-2023-155, 2023
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Cirrus and contrails considerably impact the Earths energy budget. Such ice clouds can have a positive (warming) or negative (cooling) net radiative effect (RE), which depends on cloud and ambient properties. The effect of 8 parameters on the cloud RE is estimated. In total, 94,500 radiative transfer simulations have been performed, spanning the typical parameter ranges associated with cirrus and contrails. Specific cases are selected and discussed. The generated data set is publicly available.
Ju Liang and Jim Haywood
Atmos. Chem. Phys., 23, 1687–1703, https://doi.org/10.5194/acp-23-1687-2023, https://doi.org/10.5194/acp-23-1687-2023, 2023
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The recent record-breaking flood events in China during the summer of 2021 highlight the importance of mitigating the risks from future changes in high-impact weather systems under global warming. Based on a state-of-the-art Earth system model, we demonstrate a pilot study on the responses of atmospheric rivers and extreme precipitation over East Asia to anthropogenically induced climate warming and an unconventional mitigation strategy – stratospheric aerosol injection.
Yangxin Chen, Duoying Ji, Qian Zhang, John C. Moore, Olivier Boucher, Andy Jones, Thibaut Lurton, Michael J. Mills, Ulrike Niemeier, Roland Séférian, and Simone Tilmes
Earth Syst. Dynam., 14, 55–79, https://doi.org/10.5194/esd-14-55-2023, https://doi.org/10.5194/esd-14-55-2023, 2023
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Solar geoengineering has been proposed as a way of counteracting the warming effects of increasing greenhouse gases by reflecting solar radiation. This work shows that solar geoengineering can slow down the northern-high-latitude permafrost degradation but cannot preserve the permafrost ecosystem as that under a climate of the same warming level without solar geoengineering.
Aobo Liu, John C. Moore, and Yating Chen
Earth Syst. Dynam., 14, 39–53, https://doi.org/10.5194/esd-14-39-2023, https://doi.org/10.5194/esd-14-39-2023, 2023
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Permafrost thaws and releases carbon (C) as the Arctic warms. Most earth system models (ESMs) have poor estimates of C stored now, so their future C losses are much lower than using the permafrost C model with climate inputs from six ESMs. Bias-corrected soil temperatures and plant productivity plus geoengineering lowering global temperatures from a no-mitigation baseline scenario to a moderate emissions level keep C in the soil worth about USD 0–70 (mean 20) trillion in climate damages by 2100.
Ilaria Quaglia, Claudia Timmreck, Ulrike Niemeier, Daniele Visioni, Giovanni Pitari, Christina Brodowsky, Christoph Brühl, Sandip S. Dhomse, Henning Franke, Anton Laakso, Graham W. Mann, Eugene Rozanov, and Timofei Sukhodolov
Atmos. Chem. Phys., 23, 921–948, https://doi.org/10.5194/acp-23-921-2023, https://doi.org/10.5194/acp-23-921-2023, 2023
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The last very large explosive volcanic eruption we have measurements for is the eruption of Mt. Pinatubo in 1991. It is therefore often used as a benchmark for climate models' ability to reproduce these kinds of events. Here, we compare available measurements with the results from multiple experiments conducted with climate models interactively simulating the aerosol cloud formation.
Daniele Visioni, Ewa M. Bednarz, Walker R. Lee, Ben Kravitz, Andy Jones, Jim M. Haywood, and Douglas G. MacMartin
Atmos. Chem. Phys., 23, 663–685, https://doi.org/10.5194/acp-23-663-2023, https://doi.org/10.5194/acp-23-663-2023, 2023
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The paper constitutes Part 1 of a study performing a first systematic inter-model comparison of the atmospheric responses to stratospheric sulfate aerosol injections (SAIs) at various latitudes as simulated by three state-of-the-art Earth system models. We identify similarities and differences in the modeled aerosol burden, investigate the differences in the aerosol approaches between the models, and ultimately show the differences produced in surface climate, temperature and precipitation.
Ewa M. Bednarz, Daniele Visioni, Ben Kravitz, Andy Jones, James M. Haywood, Jadwiga Richter, Douglas G. MacMartin, and Peter Braesicke
Atmos. Chem. Phys., 23, 687–709, https://doi.org/10.5194/acp-23-687-2023, https://doi.org/10.5194/acp-23-687-2023, 2023
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Building on Part 1 of this two-part study, we demonstrate the role of biases in climatological circulation and specific aspects of model microphysics in driving the differences in simulated sulfate distributions amongst three Earth system models. We then characterize the simulated changes in stratospheric and free-tropospheric temperatures, ozone, water vapor, and large-scale circulation, elucidating the role of the above aspects in the surface responses discussed in Part 1.
Kevin Wolf, Nicolas Bellouin, and Olivier Boucher
Atmos. Chem. Phys., 23, 287–309, https://doi.org/10.5194/acp-23-287-2023, https://doi.org/10.5194/acp-23-287-2023, 2023
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Recent studies estimate the radiative impact of contrails to be similar to or larger than that of emitted CO2; thus, contrail mitigation might be an opportunity to reduce the climate effects of aviation. A radiosonde data set is analyzed in terms of the vertical distribution of potential contrails, contrail mitigation by flight altitude changes, and linkages with the tropopause and jet stream. The effect of prospective jet engine developments and alternative fuels are estimated.
Jun Wang, John C. Moore, Liyun Zhao, Chao Yue, and Zhenhua Di
Earth Syst. Dynam., 13, 1625–1640, https://doi.org/10.5194/esd-13-1625-2022, https://doi.org/10.5194/esd-13-1625-2022, 2022
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We examine how geoengineering using aerosols in the atmosphere might impact urban climate in the greater Beijing region containing over 50 million people. Climate models have too coarse resolutions to resolve regional variations well, so we compare two workarounds for this – an expensive physical model and a cheaper statistical method. The statistical method generally gives a reasonable representation of climate and has limited resolution and a different seasonality from the physical model.
Jadwiga H. Richter, Daniele Visioni, Douglas G. MacMartin, David A. Bailey, Nan Rosenbloom, Brian Dobbins, Walker R. Lee, Mari Tye, and Jean-Francois Lamarque
Geosci. Model Dev., 15, 8221–8243, https://doi.org/10.5194/gmd-15-8221-2022, https://doi.org/10.5194/gmd-15-8221-2022, 2022
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Solar climate intervention using stratospheric aerosol injection is a proposed method of reducing global mean temperatures to reduce the worst consequences of climate change. We present a new modeling protocol aimed at simulating a plausible deployment of stratospheric aerosol injection and reproducibility of simulations using other Earth system models: Assessing Responses and Impacts of Solar climate intervention on the Earth system with stratospheric aerosol injection (ARISE-SAI).
Paul A. Barrett, Steven J. Abel, Hugh Coe, Ian Crawford, Amie Dobracki, James Haywood, Steve Howell, Anthony Jones, Justin Langridge, Greg M. McFarquhar, Graeme J. Nott, Hannah Price, Jens Redemann, Yohei Shinozuka, Kate Szpek, Jonathan W. Taylor, Robert Wood, Huihui Wu, Paquita Zuidema, Stéphane Bauguitte, Ryan Bennett, Keith Bower, Hong Chen, Sabrina Cochrane, Michael Cotterell, Nicholas Davies, David Delene, Connor Flynn, Andrew Freedman, Steffen Freitag, Siddhant Gupta, David Noone, Timothy B. Onasch, James Podolske, Michael R. Poellot, Sebastian Schmidt, Stephen Springston, Arthur J. Sedlacek III, Jamie Trembath, Alan Vance, Maria A. Zawadowicz, and Jianhao Zhang
Atmos. Meas. Tech., 15, 6329–6371, https://doi.org/10.5194/amt-15-6329-2022, https://doi.org/10.5194/amt-15-6329-2022, 2022
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To better understand weather and climate, it is vital to go into the field and collect observations. Often measurements take place in isolation, but here we compared data from two aircraft and one ground-based site. This was done in order to understand how well measurements made on one platform compared to those made on another. Whilst this is easy to do in a controlled laboratory setting, it is more challenging in the real world, and so these comparisons are as valuable as they are rare.
Marina Friedel, Gabriel Chiodo, Andrea Stenke, Daniela I. V. Domeisen, and Thomas Peter
Atmos. Chem. Phys., 22, 13997–14017, https://doi.org/10.5194/acp-22-13997-2022, https://doi.org/10.5194/acp-22-13997-2022, 2022
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In spring, winds the Arctic stratosphere change direction – an event called final stratospheric warming (FSW). Here, we examine whether the interannual variability in Arctic stratospheric ozone impacts the timing of the FSW. We find that Arctic ozone shifts the FSW to earlier and later dates in years with high and low ozone via the absorption of UV light. The modulation of the FSW by ozone has consequences for surface climate in ozone-rich years, which may result in better seasonal predictions.
Nora Bergner, Marina Friedel, Daniela I. V. Domeisen, Darryn Waugh, and Gabriel Chiodo
Atmos. Chem. Phys., 22, 13915–13934, https://doi.org/10.5194/acp-22-13915-2022, https://doi.org/10.5194/acp-22-13915-2022, 2022
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Polar vortex extremes, particularly situations with an unusually weak cyclonic circulation in the stratosphere, can influence the surface climate in the spring–summer time in the Southern Hemisphere. Using chemistry-climate models and observations, we evaluate the robustness of the surface impacts. While models capture the general surface response, they do not show the observed climate patterns in midlatitude regions, which we trace back to biases in the models' circulations.
Flossie Brown, Gerd A. Folberth, Stephen Sitch, Susanne Bauer, Marijn Bauters, Pascal Boeckx, Alexander W. Cheesman, Makoto Deushi, Inês Dos Santos Vieira, Corinne Galy-Lacaux, James Haywood, James Keeble, Lina M. Mercado, Fiona M. O'Connor, Naga Oshima, Kostas Tsigaridis, and Hans Verbeeck
Atmos. Chem. Phys., 22, 12331–12352, https://doi.org/10.5194/acp-22-12331-2022, https://doi.org/10.5194/acp-22-12331-2022, 2022
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Surface ozone can decrease plant productivity and impair human health. In this study, we evaluate the change in surface ozone due to climate change over South America and Africa using Earth system models. We find that if the climate were to change according to the worst-case scenario used here, models predict that forested areas in biomass burning locations and urban populations will be at increasing risk of ozone exposure, but other areas will experience a climate benefit.
Johannes Quaas, Hailing Jia, Chris Smith, Anna Lea Albright, Wenche Aas, Nicolas Bellouin, Olivier Boucher, Marie Doutriaux-Boucher, Piers M. Forster, Daniel Grosvenor, Stuart Jenkins, Zbigniew Klimont, Norman G. Loeb, Xiaoyan Ma, Vaishali Naik, Fabien Paulot, Philip Stier, Martin Wild, Gunnar Myhre, and Michael Schulz
Atmos. Chem. Phys., 22, 12221–12239, https://doi.org/10.5194/acp-22-12221-2022, https://doi.org/10.5194/acp-22-12221-2022, 2022
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Pollution particles cool climate and offset part of the global warming. However, they are washed out by rain and thus their effect responds quickly to changes in emissions. We show multiple datasets to demonstrate that aerosol emissions and their concentrations declined in many regions influenced by human emissions, as did the effects on clouds. Consequently, the cooling impact on the Earth energy budget became smaller. This change in trend implies a relative warming.
Sébastien Gardoll and Olivier Boucher
Geosci. Model Dev., 15, 7051–7073, https://doi.org/10.5194/gmd-15-7051-2022, https://doi.org/10.5194/gmd-15-7051-2022, 2022
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Tropical cyclones (TCs) are one of the most devastating natural disasters, which justifies monitoring and prediction in the context of a changing climate. In this study, we have adapted and tested a convolutional neural network (CNN) for the classification of reanalysis outputs (ERA5 and MERRA-2 labeled by HURDAT2) according to the presence or absence of TCs. We tested the impact of interpolation and of "mixing and matching" the training and test sets on the performance of the CNN.
Haoran Kang, Liyun Zhao, Michael Wolovick, and John C. Moore
The Cryosphere, 16, 3619–3633, https://doi.org/10.5194/tc-16-3619-2022, https://doi.org/10.5194/tc-16-3619-2022, 2022
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Basal thermal conditions are important to ice dynamics and sensitive to geothermal heat flux (GHF). We estimate basal thermal conditions of the Lambert–Amery Glacier system with six GHF maps. Recent GHFs inverted from aerial geomagnetic observations produce a larger warm-based area and match the observed subglacial lakes better than the other GHFs. The modelled basal melt rate is 10 to hundreds of millimetres per year in fast-flowing glaciers feeding the Amery Ice Shelf and smaller inland.
Mari R. Tye, Katherine Dagon, Maria J. Molina, Jadwiga H. Richter, Daniele Visioni, Ben Kravitz, and Simone Tilmes
Earth Syst. Dynam., 13, 1233–1257, https://doi.org/10.5194/esd-13-1233-2022, https://doi.org/10.5194/esd-13-1233-2022, 2022
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We examined the potential effect of stratospheric aerosol injection (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 the largest decreases in summer. In contrast, nighttime warming may be greatest at high latitudes in winter. SAI may reduce the frequency and intensity of extreme rainfall. The combined changes may exacerbate drying over parts of the global south.
Jim M. Haywood, Andy Jones, Ben T. Johnson, and William McFarlane Smith
Atmos. Chem. Phys., 22, 6135–6150, https://doi.org/10.5194/acp-22-6135-2022, https://doi.org/10.5194/acp-22-6135-2022, 2022
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Simulations are presented investigating the influence of moderately absorbing aerosol in the stratosphere to combat the impacts of climate change. A number of detrimental impacts are noted compared to sulfate aerosol, including (i) reduced cooling efficiency, (ii) increased deficits in global precipitation, (iii) delays in the recovery of the stratospheric ozone hole, and (iv) disruption of the stratospheric circulation and the wintertime storm tracks that impact European precipitation.
Ilaria Quaglia, Daniele Visioni, Giovanni Pitari, and Ben Kravitz
Atmos. Chem. Phys., 22, 5757–5773, https://doi.org/10.5194/acp-22-5757-2022, https://doi.org/10.5194/acp-22-5757-2022, 2022
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Carbonyl sulfide is a gas that mixes very well in the atmosphere and can reach the stratosphere, where it reacts with sunlight and produces aerosol. Here we propose that, by increasing surface fluxes by an order of magnitude, the number of stratospheric aerosols produced may be enough to partially offset the warming produced by greenhouse gases. We explore what effect this would have on the atmospheric composition.
Irina Melnikova, Olivier Boucher, Patricia Cadule, Katsumasa Tanaka, Thomas Gasser, Tomohiro Hajima, Yann Quilcaille, Hideo Shiogama, Roland Séférian, Kaoru Tachiiri, Nicolas Vuichard, Tokuta Yokohata, and Philippe Ciais
Earth Syst. Dynam., 13, 779–794, https://doi.org/10.5194/esd-13-779-2022, https://doi.org/10.5194/esd-13-779-2022, 2022
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The deployment of bioenergy crops for capturing carbon from the atmosphere facilitates global warming mitigation via generating negative CO2 emissions. Here, we explored the consequences of large-scale energy crops deployment on the land carbon cycle. The land-use change for energy crops leads to carbon emissions and loss of future potential increase in carbon uptake by natural ecosystems. This impact should be taken into account by the modeling teams and accounted for in mitigation policies.
Mengdie Xie, John C. Moore, Liyun Zhao, Michael Wolovick, and Helene Muri
Atmos. Chem. Phys., 22, 4581–4597, https://doi.org/10.5194/acp-22-4581-2022, https://doi.org/10.5194/acp-22-4581-2022, 2022
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We use data from six Earth system models to estimate Atlantic meridional overturning circulation (AMOC) changes and its drivers under four different solar geoengineering methods. Solar dimming seems relatively more effective than marine cloud brightening or stratospheric aerosol injection at reversing greenhouse-gas-driven declines in AMOC. Geoengineering-induced AMOC amelioration is due to better maintenance of air–sea temperature differences and reduced loss of Arctic summer sea ice.
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, https://doi.org/10.5194/acp-22-4557-2022, https://doi.org/10.5194/acp-22-4557-2022, 2022
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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.
Huiying Ren, Erol Cromwell, Ben Kravitz, and Xingyuan Chen
Hydrol. Earth Syst. Sci., 26, 1727–1743, https://doi.org/10.5194/hess-26-1727-2022, https://doi.org/10.5194/hess-26-1727-2022, 2022
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We used a deep learning method called long short-term memory (LSTM) to fill gaps in data collected by hydrologic monitoring networks. LSTM accounted for correlations in space and time and nonlinear trends in data. Compared to a traditional regression-based time-series method, LSTM performed comparably when filling gaps in data with smooth patterns, while it better captured highly dynamic patterns in data. Capturing such dynamics is critical for understanding dynamic complex system behaviors.
Dai Koshin, Kaoru Sato, Masashi Kohma, and Shingo Watanabe
Geosci. Model Dev., 15, 2293–2307, https://doi.org/10.5194/gmd-15-2293-2022, https://doi.org/10.5194/gmd-15-2293-2022, 2022
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The 4D ensemble Kalman filter data assimilation system for the whole neutral atmosphere has been updated. The update includes the introduction of a filter to reduce the generation of spurious waves, change in the order of horizontal diffusion of the forecast model to reproduce more realistic tidal amplitudes, and use of additional satellite observations. As a result, the analysis performance has been greatly improved, even for disturbances with periods of less than 1 d.
Davide Zanchettin, Claudia Timmreck, Myriam Khodri, Anja Schmidt, Matthew Toohey, Manabu Abe, Slimane Bekki, Jason Cole, Shih-Wei Fang, Wuhu Feng, Gabriele Hegerl, Ben Johnson, Nicolas Lebas, Allegra N. LeGrande, Graham W. Mann, Lauren Marshall, Landon Rieger, Alan Robock, Sara Rubinetti, Kostas Tsigaridis, and Helen Weierbach
Geosci. Model Dev., 15, 2265–2292, https://doi.org/10.5194/gmd-15-2265-2022, https://doi.org/10.5194/gmd-15-2265-2022, 2022
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This paper provides metadata and first analyses of the volc-pinatubo-full experiment of CMIP6-VolMIP. Results from six Earth system models reveal significant differences in radiative flux anomalies that trace back to different implementations of volcanic forcing. Surface responses are in contrast overall consistent across models, reflecting the large spread due to internal variability. A second phase of VolMIP shall consider both aspects toward improved protocol for volc-pinatubo-full.
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, https://doi.org/10.5194/acp-22-2999-2022, https://doi.org/10.5194/acp-22-2999-2022, 2022
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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.
Debra K. Weisenstein, Daniele Visioni, Henning Franke, Ulrike Niemeier, Sandro Vattioni, Gabriel Chiodo, Thomas Peter, and David W. Keith
Atmos. Chem. Phys., 22, 2955–2973, https://doi.org/10.5194/acp-22-2955-2022, https://doi.org/10.5194/acp-22-2955-2022, 2022
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This paper explores a potential method of geoengineering that could be used to slow the rate of change of climate over decadal scales. We use three climate models to explore how injections of accumulation-mode sulfuric acid aerosol change the large-scale stratospheric particle size distribution and radiative forcing response for the chosen scenarios. Radiative forcing per unit sulfur injected and relative to the change in aerosol burden is larger with particulate than with SO2 injections.
Daniel Moran, Peter-Paul Pichler, Heran Zheng, Helene Muri, Jan Klenner, Diogo Kramel, Johannes Többen, Helga Weisz, Thomas Wiedmann, Annemie Wyckmans, Anders Hammer Strømman, and Kevin R. Gurney
Earth Syst. Sci. Data, 14, 845–864, https://doi.org/10.5194/essd-14-845-2022, https://doi.org/10.5194/essd-14-845-2022, 2022
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This paper presents the modeling methods used for the website https://openghgmap.net, which provides estimates of CO2 emissions for 108 000 European cities.
Daniele Visioni, Simone Tilmes, Charles Bardeen, Michael Mills, Douglas G. MacMartin, Ben Kravitz, and Jadwiga H. Richter
Atmos. Chem. Phys., 22, 1739–1756, https://doi.org/10.5194/acp-22-1739-2022, https://doi.org/10.5194/acp-22-1739-2022, 2022
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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.
Yan Zhang, Douglas G. MacMartin, Daniele Visioni, and Ben Kravitz
Earth Syst. Dynam., 13, 201–217, https://doi.org/10.5194/esd-13-201-2022, https://doi.org/10.5194/esd-13-201-2022, 2022
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Adding SO2 to the stratosphere could temporarily cool the planet by reflecting more sunlight back to space. However, adding SO2 at different latitude(s) and season(s) leads to significant differences in regional surface climate. This study shows that, to cool the planet by 1–1.5 °C, there are likely six to eight choices of injection latitude(s) and season(s) that lead to meaningfully different distributions of climate impacts.
Nicholas A. Davis, Patrick Callaghan, Isla R. Simpson, and Simone Tilmes
Atmos. Chem. Phys., 22, 197–214, https://doi.org/10.5194/acp-22-197-2022, https://doi.org/10.5194/acp-22-197-2022, 2022
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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, https://doi.org/10.5194/acp-22-93-2022, https://doi.org/10.5194/acp-22-93-2022, 2022
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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.
John P. McCormack, V. Lynn Harvey, Cora E. Randall, Nicholas Pedatella, Dai Koshin, Kaoru Sato, Lawrence Coy, Shingo Watanabe, Fabrizio Sassi, and Laura A. Holt
Atmos. Chem. Phys., 21, 17577–17605, https://doi.org/10.5194/acp-21-17577-2021, https://doi.org/10.5194/acp-21-17577-2021, 2021
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In order to have confidence in atmospheric predictions, it is important to know how well different numerical model simulations of the Earth’s atmosphere agree with one another. This work compares four different data assimilation models that extend to or beyond the mesosphere. Results shown here demonstrate that while the models are in close agreement below ~50 km, large differences arise at higher altitudes in the mesosphere and lower thermosphere that will need to be reconciled in the future.
Rodric M. Nonki, André Lenouo, Clément Tchawoua, Christopher J. Lennard, and Ernest Amoussou
Proc. IAHS, 384, 337–342, https://doi.org/10.5194/piahs-384-337-2021, https://doi.org/10.5194/piahs-384-337-2021, 2021
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This study aims to assess the potential impacts of climate change on hydropower potential of the Lagdo dam. The results reveal that under global warming, the hydropower potential of the dam will decrease which is the result of the reduced precipitation and increase of PET, thus decrease in streamflow in the basin. This result will be take into account for future development planning in the basin.
Wouter Dorigo, Irene Himmelbauer, Daniel Aberer, Lukas Schremmer, Ivana Petrakovic, Luca Zappa, Wolfgang Preimesberger, Angelika Xaver, Frank Annor, Jonas Ardö, Dennis Baldocchi, Marco Bitelli, Günter Blöschl, Heye Bogena, Luca Brocca, Jean-Christophe Calvet, J. Julio Camarero, Giorgio Capello, Minha Choi, Michael C. Cosh, Nick van de Giesen, Istvan Hajdu, Jaakko Ikonen, Karsten H. Jensen, Kasturi Devi Kanniah, Ileen de Kat, Gottfried Kirchengast, Pankaj Kumar Rai, Jenni Kyrouac, Kristine Larson, Suxia Liu, Alexander Loew, Mahta Moghaddam, José Martínez Fernández, Cristian Mattar Bader, Renato Morbidelli, Jan P. Musial, Elise Osenga, Michael A. Palecki, Thierry Pellarin, George P. Petropoulos, Isabella Pfeil, Jarrett Powers, Alan Robock, Christoph Rüdiger, Udo Rummel, Michael Strobel, Zhongbo Su, Ryan Sullivan, Torbern Tagesson, Andrej Varlagin, Mariette Vreugdenhil, Jeffrey Walker, Jun Wen, Fred Wenger, Jean Pierre Wigneron, Mel Woods, Kun Yang, Yijian Zeng, Xiang Zhang, Marek Zreda, Stephan Dietrich, Alexander Gruber, Peter van Oevelen, Wolfgang Wagner, Klaus Scipal, Matthias Drusch, and Roberto Sabia
Hydrol. Earth Syst. Sci., 25, 5749–5804, https://doi.org/10.5194/hess-25-5749-2021, https://doi.org/10.5194/hess-25-5749-2021, 2021
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The International Soil Moisture Network (ISMN) is a community-based open-access data portal for soil water measurements taken at the ground and is accessible at https://ismn.earth. Over 1000 scientific publications and thousands of users have made use of the ISMN. The scope of this paper is to inform readers about the data and functionality of the ISMN and to provide a review of the scientific progress facilitated through the ISMN with the scope to shape future research and operations.
Chao Yue, Louise Steffensen Schmidt, Liyun Zhao, Michael Wolovick, and John C. Moore
The Cryosphere Discuss., https://doi.org/10.5194/tc-2021-318, https://doi.org/10.5194/tc-2021-318, 2021
Revised manuscript not accepted
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We use the ice sheet model PISM to estimate Vatnajökull mass balance under solar geoengineering. We find that Stratospheric aerosol injection at the rate of 5 Tg yr−1 reduces ice cap mass loss by 4 percentage points relative to the RCP4.5 scenario. Dynamic mass loss is a significant component of mass balance, but insensitive to climate forcing.
Elizaveta Malinina, Alexei Rozanov, Ulrike Niemeier, Sandra Wallis, Carlo Arosio, Felix Wrana, Claudia Timmreck, Christian von Savigny, and John P. Burrows
Atmos. Chem. Phys., 21, 14871–14891, https://doi.org/10.5194/acp-21-14871-2021, https://doi.org/10.5194/acp-21-14871-2021, 2021
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In the paper, changes in the stratospheric aerosol loading after the 2018 Ambae eruption were analyzed using OMPS-LP observations. The eruption was also simulated with the MAECHAM5-HAM global climate model. Generally, the model and observations agree very well. We attribute the good consistency of the results to a precisely determined altitude and mass of the volcanic injection, as well as nudging of the meteorological data. The radiative forcing from the eruption was estimated to be −0.13 W m−2.
Zixia Liu, Martin Osborne, Karen Anderson, Jamie D. Shutler, Andy Wilson, Justin Langridge, Steve H. L. Yim, Hugh Coe, Suresh Babu, Sreedharan K. Satheesh, Paquita Zuidema, Tao Huang, Jack C. H. Cheng, and James Haywood
Atmos. Meas. Tech., 14, 6101–6118, https://doi.org/10.5194/amt-14-6101-2021, https://doi.org/10.5194/amt-14-6101-2021, 2021
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This paper first validates the performance of an advanced aerosol observation instrument POPS against a reference instrument and examines any biases introduced by operating it on a quadcopter drone. The results show the POPS performs relatively well on the ground. The impact of the UAV rotors on the POPS is small at low wind speeds, but when operating under higher wind speeds, larger discrepancies occur. It appears that the POPS measures sub-micron aerosol particles more accurately on the UAV.
Marta Abalos, Natalia Calvo, Samuel Benito-Barca, Hella Garny, Steven C. Hardiman, Pu Lin, Martin B. Andrews, Neal Butchart, Rolando Garcia, Clara Orbe, David Saint-Martin, Shingo Watanabe, and Kohei Yoshida
Atmos. Chem. Phys., 21, 13571–13591, https://doi.org/10.5194/acp-21-13571-2021, https://doi.org/10.5194/acp-21-13571-2021, 2021
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The stratospheric Brewer–Dobson circulation (BDC), responsible for transporting mass, tracers and heat globally in the stratosphere, is evaluated in a set of state-of-the-art climate models. The acceleration of the BDC in response to increasing greenhouse gases is most robust in the lower stratosphere. At higher levels, the well-known inconsistency between model and observational BDC trends can be partly reconciled by accounting for limited sampling and large uncertainties in the observations.
Timofei Sukhodolov, Tatiana Egorova, Andrea Stenke, William T. Ball, Christina Brodowsky, Gabriel Chiodo, Aryeh Feinberg, Marina Friedel, Arseniy Karagodin-Doyennel, Thomas Peter, Jan Sedlacek, Sandro Vattioni, and Eugene Rozanov
Geosci. Model Dev., 14, 5525–5560, https://doi.org/10.5194/gmd-14-5525-2021, https://doi.org/10.5194/gmd-14-5525-2021, 2021
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This paper features the new atmosphere–ocean–aerosol–chemistry–climate model SOCOLv4.0 and its validation. The model performance is evaluated against reanalysis products and observations of atmospheric circulation and trace gas distribution, with a focus on stratospheric processes. Although we identified some problems to be addressed in further model upgrades, we demonstrated that SOCOLv4.0 is already well suited for studies related to chemistry–climate–aerosol interactions.
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, https://doi.org/10.5194/essd-13-4191-2021, https://doi.org/10.5194/essd-13-4191-2021, 2021
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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.
Dawn L. Woodard, Alexey N. Shiklomanov, Ben Kravitz, Corinne Hartin, and Ben Bond-Lamberty
Geosci. Model Dev., 14, 4751–4767, https://doi.org/10.5194/gmd-14-4751-2021, https://doi.org/10.5194/gmd-14-4751-2021, 2021
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We have added a representation of the permafrost carbon feedback to the simple, open-source global carbon–climate model Hector and calibrated the results to be consistent with historical data and Earth system model projections. Our results closely match previous work, estimating around 0.2 °C of warming from permafrost this century. This capability will be useful to explore uncertainties in this feedback and for coupling with integrated assessment models for policy and economic analysis.
Yves Balkanski, Rémy Bonnet, Olivier Boucher, Ramiro Checa-Garcia, and Jérôme Servonnat
Atmos. Chem. Phys., 21, 11423–11435, https://doi.org/10.5194/acp-21-11423-2021, https://doi.org/10.5194/acp-21-11423-2021, 2021
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Earth system models have persistent biases that impinge on our ability to make robust future regional predictions of precipitation. For the last 15 years, there has been little improvement in these biases. This work presents an accurate representation of dust absorption based upon observed dust mineralogical composition and size distribution. The striking result is that this more accurate representation improves tropical precipitations for climate models with too weak an African monsoon.
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, https://doi.org/10.5194/acp-21-10039-2021, https://doi.org/10.5194/acp-21-10039-2021, 2021
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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.
Xavier Fettweis, Stefan Hofer, Roland Séférian, Charles Amory, Alison Delhasse, Sébastien Doutreloup, Christoph Kittel, Charlotte Lang, Joris Van Bever, Florent Veillon, and Peter Irvine
The Cryosphere, 15, 3013–3019, https://doi.org/10.5194/tc-15-3013-2021, https://doi.org/10.5194/tc-15-3013-2021, 2021
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Without any reduction in our greenhouse gas emissions, the Greenland ice sheet surface mass loss can be brought in line with a medium-mitigation emissions scenario by reducing the solar downward flux at the top of the atmosphere by 1.5 %. In addition to reducing global warming, these solar geoengineering measures also dampen the well-known positive melt–albedo feedback over the ice sheet by 6 %. However, only stronger reductions in solar radiation could maintain a stable ice sheet in 2100.
Nikolas O. Aksamit, Ben Kravitz, Douglas G. MacMartin, and George Haller
Atmos. Chem. Phys., 21, 8845–8861, https://doi.org/10.5194/acp-21-8845-2021, https://doi.org/10.5194/acp-21-8845-2021, 2021
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There exist robust and influential material features evolving within turbulent fluids that behave as the skeleton for fluid transport pathways. Recent developments in applied mathematics have made the identification of these time-varying structures more rigorous and insightful than ever. Using short-range wind forecasts, we detail how and why these material features can be exploited in an effort to optimize the spread of aerosols in the stratosphere for climate geoengineering.
Henning Franke, Ulrike Niemeier, and Daniele Visioni
Atmos. Chem. Phys., 21, 8615–8635, https://doi.org/10.5194/acp-21-8615-2021, https://doi.org/10.5194/acp-21-8615-2021, 2021
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Stratospheric aerosol modification (SAM) can alter the quasi-biennial oscillation (QBO). Our simulations with two different models show that the characteristics of the QBO response are primarily determined by the meridional structure of the aerosol-induced heating. Therefore, the QBO response to SAM depends primarily on the location of injection, while injection type and rate act to scale the specific response. Our results have important implications for evaluating adverse side effects of SAM.
Antara Banerjee, Amy H. Butler, Lorenzo M. Polvani, Alan Robock, Isla R. Simpson, and Lantao Sun
Atmos. Chem. Phys., 21, 6985–6997, https://doi.org/10.5194/acp-21-6985-2021, https://doi.org/10.5194/acp-21-6985-2021, 2021
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We find that simulated stratospheric sulfate geoengineering could lead to warmer Eurasian winters alongside a drier Mediterranean and wetting to the north. These effects occur due to the strengthening of the Northern Hemisphere stratospheric polar vortex, which shifts the North Atlantic Oscillation to a more positive phase. We find the effects in our simulations to be much more significant than the wintertime effects of large tropical volcanic eruptions which inject much less sulfate aerosol.
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, https://doi.org/10.5194/acp-21-6129-2021, https://doi.org/10.5194/acp-21-6129-2021, 2021
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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).
Yuan Zhang, Olivier Boucher, Philippe Ciais, Laurent Li, and Nicolas Bellouin
Geosci. Model Dev., 14, 2029–2039, https://doi.org/10.5194/gmd-14-2029-2021, https://doi.org/10.5194/gmd-14-2029-2021, 2021
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We investigated different methods to reconstruct spatiotemporal distribution of the fraction of diffuse radiation (Fdf) to qualify the aerosol impacts on GPP using the ORCHIDEE_DF land surface model. We find that climatological-averaging methods which dampen the variability of Fdf can cause significant bias in the modeled diffuse radiation impacts on GPP. Better methods to reconstruct Fdf are recommended.
James Keeble, Birgit Hassler, Antara Banerjee, Ramiro Checa-Garcia, Gabriel Chiodo, Sean Davis, Veronika Eyring, Paul T. Griffiths, Olaf Morgenstern, Peer Nowack, Guang Zeng, Jiankai Zhang, Greg Bodeker, Susannah Burrows, Philip Cameron-Smith, David Cugnet, Christopher Danek, Makoto Deushi, Larry W. Horowitz, Anne Kubin, Lijuan Li, Gerrit Lohmann, Martine Michou, Michael J. Mills, Pierre Nabat, Dirk Olivié, Sungsu Park, Øyvind Seland, Jens Stoll, Karl-Hermann Wieners, and Tongwen Wu
Atmos. Chem. Phys., 21, 5015–5061, https://doi.org/10.5194/acp-21-5015-2021, https://doi.org/10.5194/acp-21-5015-2021, 2021
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Stratospheric ozone and water vapour are key components of the Earth system; changes to both have important impacts on global and regional climate. We evaluate changes to these species from 1850 to 2100 in the new generation of CMIP6 models. There is good agreement between the multi-model mean and observations, although there is substantial variation between the individual models. The future evolution of both ozone and water vapour is strongly dependent on the assumed future emissions scenario.
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, https://doi.org/10.5194/acp-21-4231-2021, https://doi.org/10.5194/acp-21-4231-2021, 2021
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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, https://doi.org/10.5194/acp-21-4187-2021, https://doi.org/10.5194/acp-21-4187-2021, 2021
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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.
Hanna Lee, Helene Muri, Altug Ekici, Jerry Tjiputra, and Jörg Schwinger
Earth Syst. Dynam., 12, 313–326, https://doi.org/10.5194/esd-12-313-2021, https://doi.org/10.5194/esd-12-313-2021, 2021
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We assess how three different geoengineering methods using aerosol affect land ecosystem carbon storage. Changes in temperature and precipitation play a large role in vegetation carbon uptake and storage, but our results show that increased levels of CO2 also play a considerable role. We show that there are unforeseen regional consequences under geoengineering applications, and these consequences should be taken into account in future climate policies before implementing them.
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, https://doi.org/10.5194/acp-21-3725-2021, https://doi.org/10.5194/acp-21-3725-2021, 2021
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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.
Ulrike Niemeier, Felix Riede, and Claudia Timmreck
Clim. Past, 17, 633–652, https://doi.org/10.5194/cp-17-633-2021, https://doi.org/10.5194/cp-17-633-2021, 2021
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The 13 kyr BP Laacher See eruption impacted local environments, human communities and climate. We have simulated the evolution of its fine ash and sulfur cloud such that it reflects the empirically known ash distribution. In our models, the heating of the ash causes a mesocyclone which changes the dispersion of the cloud itself, resulting in enhanced transport to low latitudes. This may partially explain why no Laacher See ash has yet been found in Greenlandic ice cores.
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, https://doi.org/10.5194/acp-21-3395-2021, https://doi.org/10.5194/acp-21-3395-2021, 2021
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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, https://doi.org/10.5194/acp-21-3317-2021, https://doi.org/10.5194/acp-21-3317-2021, 2021
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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.
Fanny Peers, Peter Francis, Steven J. Abel, Paul A. Barrett, Keith N. Bower, Michael I. Cotterell, Ian Crawford, Nicholas W. Davies, Cathryn Fox, Stuart Fox, Justin M. Langridge, Kerry G. Meyer, Steven E. Platnick, Kate Szpek, and Jim M. Haywood
Atmos. Chem. Phys., 21, 3235–3254, https://doi.org/10.5194/acp-21-3235-2021, https://doi.org/10.5194/acp-21-3235-2021, 2021
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Satellite observations at high temporal resolution are a valuable asset to monitor the transport of biomass burning plumes and the cloud diurnal cycle in the South Atlantic, but they need to be validated. Cloud and above-cloud aerosol properties retrieved from SEVIRI are compared against MODIS and measurements from the CLARIFY-2017 campaign. While some systematic differences are observed between SEVIRI and MODIS, the overall agreement in the cloud and aerosol properties is very satisfactory.
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, https://doi.org/10.5194/esd-12-253-2021, https://doi.org/10.5194/esd-12-253-2021, 2021
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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.
Sabine Robrecht, Bärbel Vogel, Simone Tilmes, and Rolf Müller
Atmos. Chem. Phys., 21, 2427–2455, https://doi.org/10.5194/acp-21-2427-2021, https://doi.org/10.5194/acp-21-2427-2021, 2021
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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.
Rupert Gladstone, Benjamin Galton-Fenzi, David Gwyther, Qin Zhou, Tore Hattermann, Chen Zhao, Lenneke Jong, Yuwei Xia, Xiaoran Guo, Konstantinos Petrakopoulos, Thomas Zwinger, Daniel Shapero, and John Moore
Geosci. Model Dev., 14, 889–905, https://doi.org/10.5194/gmd-14-889-2021, https://doi.org/10.5194/gmd-14-889-2021, 2021
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Retreat of the Antarctic ice sheet, and hence its contribution to sea level rise, is highly sensitive to melting of its floating ice shelves. This melt is caused by warm ocean currents coming into contact with the ice. Computer models used for future ice sheet projections are not able to realistically evolve these melt rates. We describe a new coupling framework to enable ice sheet and ocean computer models to interact, allowing projection of the evolution of melt and its impact on sea level.
Andy Jones, Jim M. Haywood, Anthony C. Jones, Simone Tilmes, Ben Kravitz, and Alan Robock
Atmos. Chem. Phys., 21, 1287–1304, https://doi.org/10.5194/acp-21-1287-2021, https://doi.org/10.5194/acp-21-1287-2021, 2021
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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, https://doi.org/10.5194/acp-21-1267-2021, https://doi.org/10.5194/acp-21-1267-2021, 2021
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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, https://doi.org/10.5194/acp-21-1105-2021, https://doi.org/10.5194/acp-21-1105-2021, 2021
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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.
Jim M. Haywood, Steven J. Abel, Paul A. Barrett, Nicolas Bellouin, Alan Blyth, Keith N. Bower, Melissa Brooks, Ken Carslaw, Haochi Che, Hugh Coe, Michael I. Cotterell, Ian Crawford, Zhiqiang Cui, Nicholas Davies, Beth Dingley, Paul Field, Paola Formenti, Hamish Gordon, Martin de Graaf, Ross Herbert, Ben Johnson, Anthony C. Jones, Justin M. Langridge, Florent Malavelle, Daniel G. Partridge, Fanny Peers, Jens Redemann, Philip Stier, Kate Szpek, Jonathan W. Taylor, Duncan Watson-Parris, Robert Wood, Huihui Wu, and Paquita Zuidema
Atmos. Chem. Phys., 21, 1049–1084, https://doi.org/10.5194/acp-21-1049-2021, https://doi.org/10.5194/acp-21-1049-2021, 2021
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Every year, the seasonal cycle of biomass burning from agricultural practices in Africa creates a huge plume of smoke that travels many thousands of kilometres over the Atlantic Ocean. This study provides an overview of a measurement campaign called the cloud–aerosol–radiation interaction and forcing for year 2017 (CLARIFY-2017) and documents the rationale, deployment strategy, observations, and key results from the campaign which utilized the heavily equipped FAAM atmospheric research aircraft.
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, https://doi.org/10.5194/acp-21-853-2021, https://doi.org/10.5194/acp-21-853-2021, 2021
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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.
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, https://doi.org/10.5194/acp-20-14617-2020, https://doi.org/10.5194/acp-20-14617-2020, 2020
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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, https://doi.org/10.5194/acp-20-14547-2020, https://doi.org/10.5194/acp-20-14547-2020, 2020
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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.
Walker Lee, Douglas MacMartin, Daniele Visioni, and Ben Kravitz
Earth Syst. Dynam., 11, 1051–1072, https://doi.org/10.5194/esd-11-1051-2020, https://doi.org/10.5194/esd-11-1051-2020, 2020
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The injection of aerosols into the stratosphere to reflect sunlight could reduce global warming, but this type of
geoengineeringwould also impact other variables like precipitation and sea ice. In this study, we model various climate impacts of geoengineering on a 3-D graph to show how trying to meet one climate goal will affect other variables. We also present two computer simulations which validate our model and show that geoengineering could regulate precipitation as well as temperature.
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, https://doi.org/10.5194/acp-20-13467-2020, https://doi.org/10.5194/acp-20-13467-2020, 2020
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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, https://doi.org/10.5194/acp-20-13355-2020, https://doi.org/10.5194/acp-20-13355-2020, 2020
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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.
Yuan Zhang, Ana Bastos, Fabienne Maignan, Daniel Goll, Olivier Boucher, Laurent Li, Alessandro Cescatti, Nicolas Vuichard, Xiuzhi Chen, Christof Ammann, M. Altaf Arain, T. Andrew Black, Bogdan Chojnicki, Tomomichi Kato, Ivan Mammarella, Leonardo Montagnani, Olivier Roupsard, Maria J. Sanz, Lukas Siebicke, Marek Urbaniak, Francesco Primo Vaccari, Georg Wohlfahrt, Will Woodgate, and Philippe Ciais
Geosci. Model Dev., 13, 5401–5423, https://doi.org/10.5194/gmd-13-5401-2020, https://doi.org/10.5194/gmd-13-5401-2020, 2020
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We improved the ORCHIDEE LSM by distinguishing diffuse and direct light in canopy and evaluated the new model with observations from 159 sites. Compared with the old model, the new model has better sunny GPP and reproduced the diffuse light fertilization effect observed at flux sites. Our simulations also indicate different mechanisms causing the observed GPP enhancement under cloudy conditions at different times. The new model has the potential to study large-scale impacts of aerosol changes.
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, https://doi.org/10.5194/acp-20-13011-2020, https://doi.org/10.5194/acp-20-13011-2020, 2020
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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, https://doi.org/10.5194/acp-20-12905-2020, https://doi.org/10.5194/acp-20-12905-2020, 2020
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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.
Jonathan W. Taylor, Huihui Wu, Kate Szpek, Keith Bower, Ian Crawford, Michael J. Flynn, Paul I. Williams, James Dorsey, Justin M. Langridge, Michael I. Cotterell, Cathryn Fox, Nicholas W. Davies, Jim M. Haywood, and Hugh Coe
Atmos. Chem. Phys., 20, 11201–11221, https://doi.org/10.5194/acp-20-11201-2020, https://doi.org/10.5194/acp-20-11201-2020, 2020
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Every year, huge plumes of smoke hundreds of miles wide travel over the south Atlantic Ocean from fires in central and southern Africa. These plumes absorb the sun’s energy and warm the climate. We used airborne optical instrumentation to determine how absorbing the smoke was as well as the relative importance of black and brown carbon. We also tested different ways of simulating these properties that could be used in a climate model.
Jessica Oehrlein, Gabriel Chiodo, and Lorenzo M. Polvani
Atmos. Chem. Phys., 20, 10531–10544, https://doi.org/10.5194/acp-20-10531-2020, https://doi.org/10.5194/acp-20-10531-2020, 2020
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Winter winds in the stratosphere 10–50 km above the surface impact climate at the surface. Prior studies suggest that this interaction between the stratosphere and the surface is affected by ozone. We compare two ways of including ozone in computer simulations of climate. One method is more realistic but more expensive. We find that the method of including ozone in simulations affects the surface climate when the stratospheric winds are unusually weak but not when they are unusually strong.
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., https://doi.org/10.5194/acp-2020-864, https://doi.org/10.5194/acp-2020-864, 2020
Revised manuscript not accepted
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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, https://doi.org/10.5194/acp-20-9961-2020, https://doi.org/10.5194/acp-20-9961-2020, 2020
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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.
William T. Ball, Gabriel Chiodo, Marta Abalos, Justin Alsing, and Andrea Stenke
Atmos. Chem. Phys., 20, 9737–9752, https://doi.org/10.5194/acp-20-9737-2020, https://doi.org/10.5194/acp-20-9737-2020, 2020
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Recent lower stratospheric ozone decreases remain unexplained. We show that chemistry–climate models are not generally able to reproduce mid-latitude ozone and water vapour changes. Our analysis of observations provides evidence that climate change may be responsible for the ozone trends. While model projections suggest that extratropical ozone should recover by 2100, our study raises questions about their efficacy in simulating lower stratospheric changes in this region.
Vivek K. Arora, Anna Katavouta, Richard G. Williams, Chris D. Jones, Victor Brovkin, Pierre Friedlingstein, Jörg Schwinger, Laurent Bopp, Olivier Boucher, Patricia Cadule, Matthew A. Chamberlain, James R. Christian, Christine Delire, Rosie A. Fisher, Tomohiro Hajima, Tatiana Ilyina, Emilie Joetzjer, Michio Kawamiya, Charles D. Koven, John P. Krasting, Rachel M. Law, David M. Lawrence, Andrew Lenton, Keith Lindsay, Julia Pongratz, Thomas Raddatz, Roland Séférian, Kaoru Tachiiri, Jerry F. Tjiputra, Andy Wiltshire, Tongwen Wu, and Tilo Ziehn
Biogeosciences, 17, 4173–4222, https://doi.org/10.5194/bg-17-4173-2020, https://doi.org/10.5194/bg-17-4173-2020, 2020
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Since the preindustrial period, land and ocean have taken up about half of the carbon emitted into the atmosphere by humans. Comparison of different earth system models with the carbon cycle allows us to assess how carbon uptake by land and ocean differs among models. This yields an estimate of uncertainty in our understanding of how land and ocean respond to increasing atmospheric CO2. This paper summarizes results from two such model intercomparison projects that use an idealized scenario.
Christopher J. Smith, Ryan J. Kramer, Gunnar Myhre, Kari Alterskjær, William Collins, Adriana Sima, Olivier Boucher, Jean-Louis Dufresne, Pierre Nabat, Martine Michou, Seiji Yukimoto, Jason Cole, David Paynter, Hideo Shiogama, Fiona M. O'Connor, Eddy Robertson, Andy Wiltshire, Timothy Andrews, Cécile Hannay, Ron Miller, Larissa Nazarenko, Alf Kirkevåg, Dirk Olivié, Stephanie Fiedler, Anna Lewinschal, Chloe Mackallah, Martin Dix, Robert Pincus, and Piers M. Forster
Atmos. Chem. Phys., 20, 9591–9618, https://doi.org/10.5194/acp-20-9591-2020, https://doi.org/10.5194/acp-20-9591-2020, 2020
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The spread in effective radiative forcing for both CO2 and aerosols is narrower in the latest CMIP6 (Coupled Model Intercomparison Project) generation than in CMIP5. For the case of CO2 it is likely that model radiation parameterisations have improved. Tropospheric and stratospheric radiative adjustments to the forcing behave differently for different forcing agents, and there is still significant diversity in how clouds respond to forcings, particularly for total anthropogenic forcing.
Bethany Sutherland, Ben Kravitz, Philip J. Rasch, and Hailong Wang
Geosci. Model Dev. Discuss., https://doi.org/10.5194/gmd-2020-228, https://doi.org/10.5194/gmd-2020-228, 2020
Preprint withdrawn
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Through a cascade of physical mechanisms, a change in one location can trigger a response in a different location. These responses and the mechanisms that cause them are difficult to detect. Here we propose a method, using global climate models, to detect possible relationships between changes in one region and responses throughout the globe caused by that change. A change in the Pacific ocean is used as a test case to determine the effectiveness of the method.
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, https://doi.org/10.5194/esd-11-673-2020, https://doi.org/10.5194/esd-11-673-2020, 2020
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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, https://doi.org/10.5194/acp-20-8975-2020, https://doi.org/10.5194/acp-20-8975-2020, 2020
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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.
Gunnar Myhre, Bjørn H. Samset, Christian W. Mohr, Kari Alterskjær, Yves Balkanski, Nicolas Bellouin, Mian Chin, James Haywood, Øivind Hodnebrog, Stefan Kinne, Guangxing Lin, Marianne T. Lund, Joyce E. Penner, Michael Schulz, Nick Schutgens, Ragnhild B. Skeie, Philip Stier, Toshihiko Takemura, and Kai Zhang
Atmos. Chem. Phys., 20, 8855–8865, https://doi.org/10.5194/acp-20-8855-2020, https://doi.org/10.5194/acp-20-8855-2020, 2020
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The radiative forcing of the direct aerosol effects can be decomposed into clear-sky and cloudy-sky portions. In this study we use observational methods and two sets of multi-model global aerosol simulations over the industrial era to show that the contribution from cloudy-sky regions is likely weak.
Prodromos Zanis, Dimitris Akritidis, Aristeidis K. Georgoulias, Robert J. Allen, Susanne E. Bauer, Olivier Boucher, Jason Cole, Ben Johnson, Makoto Deushi, Martine Michou, Jane Mulcahy, Pierre Nabat, Dirk Olivié, Naga Oshima, Adriana Sima, Michael Schulz, Toshihiko Takemura, and Konstantinos Tsigaridis
Atmos. Chem. Phys., 20, 8381–8404, https://doi.org/10.5194/acp-20-8381-2020, https://doi.org/10.5194/acp-20-8381-2020, 2020
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In this work, we use Coupled Model Intercomparison Project Phase 6 (CMIP6) simulations from 10 Earth system models (ESMs) and general circulation models (GCMs) to study the fast climate responses on pre-industrial climate, due to present-day aerosols. All models carried out two sets of simulations: a control experiment with all forcings set to the year 1850 and a perturbation experiment with all forcings identical to the control, except for aerosols with precursor emissions set to the year 2014.
Nicolas Bellouin, Will Davies, Keith P. Shine, Johannes Quaas, Johannes Mülmenstädt, Piers M. Forster, Chris Smith, Lindsay Lee, Leighton Regayre, Guy Brasseur, Natalia Sudarchikova, Idir Bouarar, Olivier Boucher, and Gunnar Myhre
Earth Syst. Sci. Data, 12, 1649–1677, https://doi.org/10.5194/essd-12-1649-2020, https://doi.org/10.5194/essd-12-1649-2020, 2020
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Quantifying the imbalance in the Earth's energy budget caused by human activities is important to understand and predict climate changes. This study presents new estimates of the imbalance caused by changes in atmospheric concentrations of carbon dioxide, methane, ozone, and particles of pollution. Over the period 2003–2017, the overall imbalance has been positive, indicating that the climate system has gained energy and will warm further.
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, https://doi.org/10.5194/esd-11-579-2020, https://doi.org/10.5194/esd-11-579-2020, 2020
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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.
Dai Koshin, Kaoru Sato, Kazuyuki Miyazaki, and Shingo Watanabe
Geosci. Model Dev., 13, 3145–3177, https://doi.org/10.5194/gmd-13-3145-2020, https://doi.org/10.5194/gmd-13-3145-2020, 2020
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A new data assimilation system with a 4D local ensemble transform Kalman filter for the whole neutral atmosphere is developed using a T42L124 general circulation model. A conventional observation dataset and bias-corrected satellite temperature data are assimilated. After the improvements of the forecast model, the assimilation parameters are optimized. The minimum optimal number of ensembles is also examined. Results are evaluated using the reanalysis data and independent radar observations.
Pierre Sepulchre, Arnaud Caubel, Jean-Baptiste Ladant, Laurent Bopp, Olivier Boucher, Pascale Braconnot, Patrick Brockmann, Anne Cozic, Yannick Donnadieu, Jean-Louis Dufresne, Victor Estella-Perez, Christian Ethé, Frédéric Fluteau, Marie-Alice Foujols, Guillaume Gastineau, Josefine Ghattas, Didier Hauglustaine, Frédéric Hourdin, Masa Kageyama, Myriam Khodri, Olivier Marti, Yann Meurdesoif, Juliette Mignot, Anta-Clarisse Sarr, Jérôme Servonnat, Didier Swingedouw, Sophie Szopa, and Delphine Tardif
Geosci. Model Dev., 13, 3011–3053, https://doi.org/10.5194/gmd-13-3011-2020, https://doi.org/10.5194/gmd-13-3011-2020, 2020
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Our paper describes IPSL-CM5A2, an Earth system model that can be integrated for long (several thousands of years) climate simulations. We describe the technical aspects, assess the model computing performance and evaluate the strengths and weaknesses of the model, by comparing pre-industrial and historical runs to the previous-generation model simulations and to observations. We also present a Cretaceous simulation as a case study to show how the model simulates deep-time paleoclimates.
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., https://doi.org/10.5194/acp-2020-525, https://doi.org/10.5194/acp-2020-525, 2020
Preprint withdrawn
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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.
Tomohiro Hajima, Michio Watanabe, Akitomo Yamamoto, Hiroaki Tatebe, Maki A. Noguchi, Manabu Abe, Rumi Ohgaito, Akinori Ito, Dai Yamazaki, Hideki Okajima, Akihiko Ito, Kumiko Takata, Koji Ogochi, Shingo Watanabe, and Michio Kawamiya
Geosci. Model Dev., 13, 2197–2244, https://doi.org/10.5194/gmd-13-2197-2020, https://doi.org/10.5194/gmd-13-2197-2020, 2020
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We developed a new Earth system model (ESM) named MIROC-ES2L. This model is based on a state-of-the-art climate model and includes carbon–nitrogen cycles for the land and multiple biogeochemical cycles for the ocean. The model's performances on reproducing historical climate and biogeochemical changes are confirmed to be reasonable, and the new model is likely to be an
optimisticmodel in projecting future climate change among ESMs in the Coupled Model Intercomparison Project Phase 6.
William T. Morgan, James D. Allan, Stéphane Bauguitte, Eoghan Darbyshire, Michael J. Flynn, James Lee, Dantong Liu, Ben Johnson, Jim Haywood, Karla M. Longo, Paulo E. Artaxo, and Hugh Coe
Atmos. Chem. Phys., 20, 5309–5326, https://doi.org/10.5194/acp-20-5309-2020, https://doi.org/10.5194/acp-20-5309-2020, 2020
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We flew a large atmospheric research aircraft across a number of different environments in the Amazon basin during the 2012 biomass burning season. Smoke from fires builds up and has a significant impact on weather, climate, health and natural ecosystems. Our goal was to quantify changes in the properties of the smoke emitted by fires as it is transported through the atmosphere. We found that the major control on the properties of the smoke was due to differences in the fires themselves.
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, https://doi.org/10.5194/acp-20-4607-2020, https://doi.org/10.5194/acp-20-4607-2020, 2020
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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.
Theodore Weber, Austin Corotan, Brian Hutchinson, Ben Kravitz, and Robert Link
Atmos. Chem. Phys., 20, 2303–2317, https://doi.org/10.5194/acp-20-2303-2020, https://doi.org/10.5194/acp-20-2303-2020, 2020
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Climate model emulators can save computer time but are less accurate than full climate models. We use neural networks to build emulators of precipitation, trained on existing climate model runs. By doing so, we can capture nonlinearities and how the past state of a model (to some degree) shapes the future state. Our emulator outperforms a persistence forecast of precipitation.
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, https://doi.org/10.5194/acp-20-1341-2020, https://doi.org/10.5194/acp-20-1341-2020, 2020
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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.
Xiaoran Guo, Liyun Zhao, Rupert M. Gladstone, Sainan Sun, and John C. Moore
The Cryosphere, 13, 3139–3153, https://doi.org/10.5194/tc-13-3139-2019, https://doi.org/10.5194/tc-13-3139-2019, 2019
Elizabeth Asher, Rebecca S. Hornbrook, Britton B. Stephens, Doug Kinnison, Eric J. Morgan, Ralph F. Keeling, Elliot L. Atlas, Sue M. Schauffler, Simone Tilmes, Eric A. Kort, Martin S. Hoecker-Martínez, Matt C. Long, Jean-François Lamarque, Alfonso Saiz-Lopez, Kathryn McKain, Colm Sweeney, Alan J. Hills, and Eric C. Apel
Atmos. Chem. Phys., 19, 14071–14090, https://doi.org/10.5194/acp-19-14071-2019, https://doi.org/10.5194/acp-19-14071-2019, 2019
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Halogenated organic trace gases, which are a source of reactive halogens to the atmosphere, exert a disproportionately large influence on atmospheric chemistry and climate. This paper reports novel aircraft observations of halogenated compounds over the Southern Ocean in summer and evaluates hypothesized regional sources and emissions of these trace gases through their relationships to additional aircraft observations.
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, https://doi.org/10.5194/acp-19-13701-2019, https://doi.org/10.5194/acp-19-13701-2019, 2019
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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.
Samuel Rémy, Zak Kipling, Johannes Flemming, Olivier Boucher, Pierre Nabat, Martine Michou, Alessio Bozzo, Melanie Ades, Vincent Huijnen, Angela Benedetti, Richard Engelen, Vincent-Henri Peuch, and Jean-Jacques Morcrette
Geosci. Model Dev., 12, 4627–4659, https://doi.org/10.5194/gmd-12-4627-2019, https://doi.org/10.5194/gmd-12-4627-2019, 2019
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This article describes the IFS-AER aerosol module used operationally in the Integrated Forecasting System (IFS) cycle 45R1, operated by the ECMWF in the framework of the Copernicus Atmospheric Monitoring Services (CAMS). We describe the different parameterizations for aerosol sources, sinks, and how the aerosols are integrated in the larger atmospheric composition forecasting system. The skill of PM and AOD simulations against observations is improved compared to the older cycle 40R2.
James Brooks, Dantong Liu, James D. Allan, Paul I. Williams, Jim Haywood, Ellie J. Highwood, Sobhan K. Kompalli, S. Suresh Babu, Sreedharan K. Satheesh, Andrew G. Turner, and Hugh Coe
Atmos. Chem. Phys., 19, 13079–13096, https://doi.org/10.5194/acp-19-13079-2019, https://doi.org/10.5194/acp-19-13079-2019, 2019
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Our study presents an analysis of the vertical and horizontal black carbon properties across northern India using aircraft measurements. The Indo-Gangetic Plain saw the greatest black carbon mass concentrations during the pre-monsoon season. Two black carbon modes were recorded: a small black carbon mode (traffic emissions) in the north-west and a moderately coated mode (solid-fuel emissions) in the Indo-Gangetic Plain. In the vertical profile, absorption properties increase with height.
Pankaj Sadavarte, Maheswar Rupakheti, Prakash Bhave, Kiran Shakya, and Mark Lawrence
Atmos. Chem. Phys., 19, 12953–12973, https://doi.org/10.5194/acp-19-12953-2019, https://doi.org/10.5194/acp-19-12953-2019, 2019
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Emission inventory studies are an important regulatory tool for quantifying the amount of pollutants released in the atmosphere using the fuel consumption and emission rates for different fuels. This study developed an emission inventory over Nepal for 2001–2016 that reveals the changing fuel consumption and subsequently the pollution across different sectors of industrial, transport, agricultural, commercial and residential uses with the use of spatial distribution of anthropogenic activities.
Wenxiu Sun, Peter Hess, Gang Chen, and Simone Tilmes
Atmos. Chem. Phys., 19, 12917–12933, https://doi.org/10.5194/acp-19-12917-2019, https://doi.org/10.5194/acp-19-12917-2019, 2019
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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, https://doi.org/10.5194/acp-19-12887-2019, https://doi.org/10.5194/acp-19-12887-2019, 2019
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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, https://doi.org/10.5194/acp-19-11559-2019, https://doi.org/10.5194/acp-19-11559-2019, 2019
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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.
Ulrike Niemeier, Claudia Timmreck, and Kirstin Krüger
Atmos. Chem. Phys., 19, 10379–10390, https://doi.org/10.5194/acp-19-10379-2019, https://doi.org/10.5194/acp-19-10379-2019, 2019
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In 1963 Mt. Agung, Indonesia, showed unrest for several months. During this period,
two medium-sized eruptions injected SO2 into the stratosphere. Recent volcanic emission datasets include only one large eruption phase. Therefore, we compared model experiments, with (a) one larger eruption and (b) two eruptions as observed. The evolution of the volcanic cloud differs significantly between the two experiments. Both climatic eruptions should be taken into account.
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, https://doi.org/10.5194/acp-19-10087-2019, https://doi.org/10.5194/acp-19-10087-2019, 2019
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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.
Fanny Peers, Peter Francis, Cathryn Fox, Steven J. Abel, Kate Szpek, Michael I. Cotterell, Nicholas W. Davies, Justin M. Langridge, Kerry G. Meyer, Steven E. Platnick, and Jim M. Haywood
Atmos. Chem. Phys., 19, 9595–9611, https://doi.org/10.5194/acp-19-9595-2019, https://doi.org/10.5194/acp-19-9595-2019, 2019
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The measurements from the geostationary satellite MSG/SEVIRI are used to retrieve the cloud and above-cloud aerosol properties over the South Atlantic. The technique relies on the spectral contrast and the magnitude of the signal in the visible to shortwave infrared region as well as the atmospheric correction based on forecasted water vapour profiles. The sensitivity analysis and the stability of the retrieval over time show great potential of the high-temporal-resolution observations.
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, https://doi.org/10.5194/acp-19-9253-2019, https://doi.org/10.5194/acp-19-9253-2019, 2019
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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.
Hiroaki Tatebe, Tomoo Ogura, Tomoko Nitta, Yoshiki Komuro, Koji Ogochi, Toshihiko Takemura, Kengo Sudo, Miho Sekiguchi, Manabu Abe, Fuyuki Saito, Minoru Chikira, Shingo Watanabe, Masato Mori, Nagio Hirota, Yoshio Kawatani, Takashi Mochizuki, Kei Yoshimura, Kumiko Takata, Ryouta O'ishi, Dai Yamazaki, Tatsuo Suzuki, Masao Kurogi, Takahito Kataoka, Masahiro Watanabe, and Masahide Kimoto
Geosci. Model Dev., 12, 2727–2765, https://doi.org/10.5194/gmd-12-2727-2019, https://doi.org/10.5194/gmd-12-2727-2019, 2019
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For a deeper understanding of a wide range of climate science issues, the latest version of the Japanese climate model, called MIROC6, was developed. The climate model represents observed mean climate and climate variations well, for example tropical precipitation, the midlatitude westerlies, and the East Asian monsoon, which influence human activity all over the world. The improved climate simulations could add reliability to climate predictions under global warming.
Nicholas W. Davies, Cathryn Fox, Kate Szpek, Michael I. Cotterell, Jonathan W. Taylor, James D. Allan, Paul I. Williams, Jamie Trembath, Jim M. Haywood, and Justin M. Langridge
Atmos. Meas. Tech., 12, 3417–3434, https://doi.org/10.5194/amt-12-3417-2019, https://doi.org/10.5194/amt-12-3417-2019, 2019
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This research project assesses biases in traditional, filter-based, aerosol absorption measurements by comparison to state-of-the-art, non-filter-based, or in situ, measurements. We assess biases in traditional absorption measurements for three main aerosol types, including dust and fresh and aged biomass burning aerosols. The main results of this study are that the traditional and state-of-the-art absorption measurements are well correlated and that biases in the former are up to 45 %.
James Brooks, James D. Allan, Paul I. Williams, Dantong Liu, Cathryn Fox, Jim Haywood, Justin M. Langridge, Ellie J. Highwood, Sobhan K. Kompalli, Debbie O'Sullivan, Suresh S. Babu, Sreedharan K. Satheesh, Andrew G. Turner, and Hugh Coe
Atmos. Chem. Phys., 19, 5615–5634, https://doi.org/10.5194/acp-19-5615-2019, https://doi.org/10.5194/acp-19-5615-2019, 2019
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Our study, for the first time, presents measurements of aerosol chemical composition and physical characteristics across northern India in the pre-monsoon and monsoon seasons of 2016 using the FAAM BAe-146 UK research aircraft. Across northern India, an elevated aerosol layer dominated by sulfate aerosol exists that diminishes with monsoon arrival. The Indo-Gangetic Plain (IGP) boundary layer is dominated by organics, whereas outside the IGP sulfate dominates with increased scattering aerosol.
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, https://doi.org/10.5194/acp-19-5511-2019, https://doi.org/10.5194/acp-19-5511-2019, 2019
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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.
Michael I. Cotterell, Andrew J. Orr-Ewing, Kate Szpek, Jim M. Haywood, and Justin M. Langridge
Atmos. Meas. Tech., 12, 2371–2385, https://doi.org/10.5194/amt-12-2371-2019, https://doi.org/10.5194/amt-12-2371-2019, 2019
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Photoacoustic spectroscopy provides measurements of absorption coefficient for aerosol and gas samples but requires careful calibration, and researchers often use concentrations of ozone. Recent work has shown that the bath gas composition impacts the accuracy of this calibration at visible wavelengths. We explore further the role of bath gas, demonstrating that the calibration accuracy is optimal for a bath gas composed of 20 % oxygen and 80 % nitrogen at wavelengths of 405, 514 and 658 nm.
Robert Link, Abigail Snyder, Cary Lynch, Corinne Hartin, Ben Kravitz, and Ben Bond-Lamberty
Geosci. Model Dev., 12, 1477–1489, https://doi.org/10.5194/gmd-12-1477-2019, https://doi.org/10.5194/gmd-12-1477-2019, 2019
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Earth system models (ESMs) produce the highest-quality future climate data available, but they are costly to run, so only a few runs from each model are publicly available. What is needed are emulators that tell us what would have happened, if we had been able to perform as many ESM runs as we might have liked. Much of the existing work on emulators has focused on deterministic projections of average values. Here we present a way to imbue emulators with the variability seen in ESM runs.
Xin Wan, Shichang Kang, Maheswar Rupakheti, Qianggong Zhang, Lekhendra Tripathee, Junming Guo, Pengfei Chen, Dipesh Rupakheti, Arnico K. Panday, Mark G. Lawrence, Kimitaka Kawamura, and Zhiyuan Cong
Atmos. Chem. Phys., 19, 2725–2747, https://doi.org/10.5194/acp-19-2725-2019, https://doi.org/10.5194/acp-19-2725-2019, 2019
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The sources of primary and secondary aerosols in the Hindu Kush–Himalayan–Tibetan Plateau region are not well known. Organic molecular tracers are useful for aerosol source apportionment. The characterization of molecular tracers were first systemically investigated and the contribution from primary and secondary sources to carbonaceous aerosols was estimated in the Kathmandu Valley. Our results demonstrate that biomass burning contributed a significant fraction to OC in the Kathmandu Valley.
Sauvik Santra, Shubha Verma, Koji Fujita, Indrajit Chakraborty, Olivier Boucher, Toshihiko Takemura, John F. Burkhart, Felix Matt, and Mukesh Sharma
Atmos. Chem. Phys., 19, 2441–2460, https://doi.org/10.5194/acp-19-2441-2019, https://doi.org/10.5194/acp-19-2441-2019, 2019
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The present study provided information on specific glaciers over the Hindu Kush Himalayan region identified as being vulnerable to BC-induced impacts (affected by high BC-induced snow albedo reduction in addition to being sensitive to BC-induced impacts), thus impacting the downstream hydrology. The source-specific contribution to atmospheric BC aerosols by emission sources led to identifying the potential emission source, which was distinctive over south and north to 30° N.
Jeronimo Escribano, Alessio Bozzo, Philippe Dubuisson, Johannes Flemming, Robin J. Hogan, Laurent C.-Labonnote, and Olivier Boucher
Geosci. Model Dev., 12, 805–827, https://doi.org/10.5194/gmd-12-805-2019, https://doi.org/10.5194/gmd-12-805-2019, 2019
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Accurate shortwave radiance computations are becoming increasingly important for some applications in atmospheric composition. In this work we propose a benchmark protocol and dataset to asses the accuracy and computing runtime of radiance calculations of radiative transfer models. It is applied to four models, showing the potential of this benchmark to evaluate the model performance under a variety of atmospheric conditions, viewing geometries, aerosol loading, and optical properties.
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, https://doi.org/10.5194/acp-19-921-2019, https://doi.org/10.5194/acp-19-921-2019, 2019
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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.
Ashish Singh, Khadak S. Mahata, Maheswar Rupakheti, Wolfgang Junkermann, Arnico K. Panday, and Mark G. Lawrence
Atmos. Chem. Phys., 19, 245–258, https://doi.org/10.5194/acp-19-245-2019, https://doi.org/10.5194/acp-19-245-2019, 2019
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This paper reports the first airborne measurement campaign in the central Himalayan foothill region, one of the polluted but relatively poorly sampled regions of the world. The measurement campaign quantifies the vertical distribution of aerosols over a polluted mountain valley in the Himalayan foothills and investigates the extent of regional emission transport.
Christopher G. Fletcher, Ben Kravitz, and Bakr Badawy
Atmos. Chem. Phys., 18, 17529–17543, https://doi.org/10.5194/acp-18-17529-2018, https://doi.org/10.5194/acp-18-17529-2018, 2018
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The most important number for future climate projections is Earth's climate sensitivity (CS), or how much warming will result from increased carbon dioxide. We cannot know the true CS, and estimates of CS from climate models have a wide range. This study identifies the major factors that control this range, and we show that the choice of methods used in creating a climate model are three times more important than fine-tuning the details of the model after it is created.
Rupert M. Gladstone, Yuwei Xia, and John Moore
The Cryosphere, 12, 3605–3615, https://doi.org/10.5194/tc-12-3605-2018, https://doi.org/10.5194/tc-12-3605-2018, 2018
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Computer models for the simulation of marine ice sheets (ice sheets resting on bedrock below sea level) historically show poor numerical convergence for grounding line (the boundary between grounded and floating parts of the ice sheet) movement. We have further characterised the nature of the numerical problems leading to poor convergence and highlighted implications for the design of computer experiments that test grounding line movement.
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, https://doi.org/10.5194/acp-18-16155-2018, https://doi.org/10.5194/acp-18-16155-2018, 2018
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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.
Liren Wei, Duoying Ji, Chiyuan Miao, Helene Muri, and John C. Moore
Atmos. Chem. Phys., 18, 16033–16050, https://doi.org/10.5194/acp-18-16033-2018, https://doi.org/10.5194/acp-18-16033-2018, 2018
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We analyzed streamflow and flood frequency under the stratospheric aerosol geoengineering scenario simulated by climate models. Stratospheric aerosol geoengineering appears to reduce flood risk in most regions, but the overall effects are largely determined by the large-scale geographic pattern. Over the Amazon, stratospheric aerosol geoengineering ameliorates the drying trend here under a future warming climate.
Rumi Ohgaito, Ayako Abe-Ouchi, Ryouta O'ishi, Toshihiko Takemura, Akinori Ito, Tomohiro Hajima, Shingo Watanabe, and Michio Kawamiya
Clim. Past, 14, 1565–1581, https://doi.org/10.5194/cp-14-1565-2018, https://doi.org/10.5194/cp-14-1565-2018, 2018
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The behaviour of dust in terms of climate can be investigated using past climate. The Last Glacial Maximum (LGM; 21000 years before present) is known to be dustier. We investigated the impact of plausible dust distribution on the climate of the LGM using an Earth system model and found that the higher dust load results in less cooling over the polar regions. The main finding is that radiative perturbation by the high dust loading does not necessarily cool the surface surrounding Antarctica.
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, https://doi.org/10.5194/acp-18-15581-2018, https://doi.org/10.5194/acp-18-15581-2018, 2018
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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, https://doi.org/10.5194/acp-18-14867-2018, https://doi.org/10.5194/acp-18-14867-2018, 2018
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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, https://doi.org/10.5194/gmd-11-4155-2018, https://doi.org/10.5194/gmd-11-4155-2018, 2018
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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.
Khadak Singh Mahata, Maheswar Rupakheti, Arnico Kumar Panday, Piyush Bhardwaj, Manish Naja, Ashish Singh, Andrea Mues, Paolo Cristofanelli, Deepak Pudasainee, Paolo Bonasoni, and Mark G. Lawrence
Atmos. Chem. Phys., 18, 14113–14132, https://doi.org/10.5194/acp-18-14113-2018, https://doi.org/10.5194/acp-18-14113-2018, 2018
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This paper presents the first-time simultaneous measurement of CO and O3 at multiple sites in the Kathmandu Valley bottom, its mountain rim and a river outlet, providing their spatial, temporal and seasonal–diurnal variations. Our study reveals that high O3, especially during premonsoon, in observed sites is of high concern for human health and ecosystems in the region. We also estimated CO emission flux to be 2–14 times higher than widely used emission databases (EDGAR HTAP, REAS and INTEX-B).
Michael J. Wolovick and John C. Moore
The Cryosphere, 12, 2955–2967, https://doi.org/10.5194/tc-12-2955-2018, https://doi.org/10.5194/tc-12-2955-2018, 2018
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In this paper, we explore the possibility of using locally targeted geoengineering to slow the rate of an ice sheet collapse. We find that an intervention as big as existing large civil engineering projects could have a 30 % probability of stopping an ice sheet collapse, while larger interventions have better odds of success. With more research to improve upon the simple designs we considered, it may be possible to perfect a design that was both achievable and had good odds of success.
Ben Kravitz, Philip J. Rasch, Hailong Wang, Alan Robock, Corey Gabriel, Olivier Boucher, Jason N. S. Cole, Jim Haywood, Duoying Ji, Andy Jones, Andrew Lenton, John C. Moore, Helene Muri, Ulrike Niemeier, Steven Phipps, Hauke Schmidt, Shingo Watanabe, Shuting Yang, and Jin-Ho Yoon
Atmos. Chem. Phys., 18, 13097–13113, https://doi.org/10.5194/acp-18-13097-2018, https://doi.org/10.5194/acp-18-13097-2018, 2018
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Marine cloud brightening has been proposed as a means of geoengineering/climate intervention, or deliberately altering the climate system to offset anthropogenic climate change. In idealized simulations that highlight contrasts between land and ocean, we find that the globe warms, including the ocean due to transport of heat from land. This study reinforces that no net energy input into the Earth system does not mean that temperature will necessarily remain unchanged.
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, https://doi.org/10.5194/acp-18-12223-2018, https://doi.org/10.5194/acp-18-12223-2018, 2018
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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.
Piyush Bhardwaj, Manish Naja, Maheswar Rupakheti, Aurelia Lupascu, Andrea Mues, Arnico Kumar Panday, Rajesh Kumar, Khadak Singh Mahata, Shyam Lal, Harish C. Chandola, and Mark G. Lawrence
Atmos. Chem. Phys., 18, 11949–11971, https://doi.org/10.5194/acp-18-11949-2018, https://doi.org/10.5194/acp-18-11949-2018, 2018
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This study provides information about the regional variabilities in some of the pollutants using observations in Nepal and India. It is shown that agricultural crop residue burning leads to a significant enhancement in ozone and CO over a wider region. Further, the wintertime higher ozone levels are shown to be largely due to local emissions, while regional transport could be important in spring and hence shows the role of regional sources versus local sources in the Kathmandu Valley.
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, https://doi.org/10.5194/acp-18-11927-2018, https://doi.org/10.5194/acp-18-11927-2018, 2018
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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.
Peter J. Irvine, David W. Keith, and John Moore
The Cryosphere, 12, 2501–2513, https://doi.org/10.5194/tc-12-2501-2018, https://doi.org/10.5194/tc-12-2501-2018, 2018
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Stratospheric aerosol geoengineering, a form of solar geoengineering, is a proposal to add a reflective layer of aerosol to the upper atmosphere. This would reduce sea level rise by slowing the melting of ice on land and the thermal expansion of the oceans. However, there is considerable uncertainty about its potential efficacy. This article highlights key uncertainties in the sea level response to solar geoengineering and recommends approaches to address these in future work.
Angela Benedetti, Jeffrey S. Reid, Peter Knippertz, John H. Marsham, Francesca Di Giuseppe, Samuel Rémy, Sara Basart, Olivier Boucher, Ian M. Brooks, Laurent Menut, Lucia Mona, Paolo Laj, Gelsomina Pappalardo, Alfred Wiedensohler, Alexander Baklanov, Malcolm Brooks, Peter R. Colarco, Emilio Cuevas, Arlindo da Silva, Jeronimo Escribano, Johannes Flemming, Nicolas Huneeus, Oriol Jorba, Stelios Kazadzis, Stefan Kinne, Thomas Popp, Patricia K. Quinn, Thomas T. Sekiyama, Taichu Tanaka, and Enric Terradellas
Atmos. Chem. Phys., 18, 10615–10643, https://doi.org/10.5194/acp-18-10615-2018, https://doi.org/10.5194/acp-18-10615-2018, 2018
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Numerical prediction of aerosol particle properties has become an important activity at many research and operational weather centers. This development is due to growing interest from a diverse set of stakeholders, such as air quality regulatory bodies, aviation authorities, solar energy plant managers, climate service providers, and health professionals. This paper describes the advances in the field and sets out requirements for observations for the sustainability of these activities.
Duoying Ji, Songsong Fang, Charles L. Curry, Hiroki Kashimura, Shingo Watanabe, Jason N. S. Cole, Andrew Lenton, Helene Muri, Ben Kravitz, and John C. Moore
Atmos. Chem. Phys., 18, 10133–10156, https://doi.org/10.5194/acp-18-10133-2018, https://doi.org/10.5194/acp-18-10133-2018, 2018
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We examine extreme temperature and precipitation under climate-model-simulated solar dimming and stratospheric aerosol injection geoengineering schemes. Both types of geoengineering lead to lower minimum temperatures at higher latitudes and greater cooling of minimum temperatures and maximum temperatures over land compared with oceans. Stratospheric aerosol injection is more effective in reducing tropical extreme precipitation, while solar dimming is more effective over extra-tropical regions.
Qin Wang, John C. Moore, and Duoying Ji
Atmos. Chem. Phys., 18, 9173–9188, https://doi.org/10.5194/acp-18-9173-2018, https://doi.org/10.5194/acp-18-9173-2018, 2018
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(1) Genesis potential and ventilation indices are assessed in 6 ESMs running RCP4.5 and G4, in 6 tropical cyclone genesis basins.
(2) Genesis potential is reasonably well parameterized by simple surface temperature, but other factors are important in different basins and models such as relative humidity and wind shear.
(3) The Northern Hemisphere basins behave rather differently from the southern ones, and these dominate TC statistics. G4 leads to significantly fewer TCs globally than RCP4.5.
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, https://doi.org/10.5194/acp-18-8953-2018, https://doi.org/10.5194/acp-18-8953-2018, 2018
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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.
Erika von Schneidemesser, Boris Bonn, Tim M. Butler, Christian Ehlers, Holger Gerwig, Hannele Hakola, Heidi Hellén, Andreas Kerschbaumer, Dieter Klemp, Claudia Kofahl, Jürgen Kura, Anja Lüdecke, Rainer Nothard, Axel Pietsch, Jörn Quedenau, Klaus Schäfer, James J. Schauer, Ashish Singh, Ana-Maria Villalobos, Matthias Wiegner, and Mark G. Lawrence
Atmos. Chem. Phys., 18, 8621–8645, https://doi.org/10.5194/acp-18-8621-2018, https://doi.org/10.5194/acp-18-8621-2018, 2018
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This paper provides an overview of the measurements done at an urban background site in Berlin from June-August of 2014. Results show that natural source contributions to ozone and particulate matter (PM) air pollutants are substantial. Large contributions of secondary aerosols formed in the atmosphere to PM10 concentrations were quantified. An analysis of the sources also identified contributions to PM from plant-based sources, vehicles, and a small contribution from wood burning.
Anboyu Guo, John C. Moore, and Duoying Ji
Atmos. Chem. Phys., 18, 8689–8706, https://doi.org/10.5194/acp-18-8689-2018, https://doi.org/10.5194/acp-18-8689-2018, 2018
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This is an examination of both the zonal and meridional tropical circulations under G1 geoengineering using eight ESMs. Drivers of the changes are examined, with meridional temperature gradient being the dominant factor. The Hadley circulation is changed under G1 differently for each hemisphere, but changes are small compared with abrupt4xCO2. Changes in the Walker circulation are subtle but potentially important in some regions, and ENSO impacts circulations only slightly differently under G1.
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, https://doi.org/10.5194/acp-18-8373-2018, https://doi.org/10.5194/acp-18-8373-2018, 2018
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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, https