Large-scale tropospheric transport in the Chemistry-Climate Model Initiative (CCMI) simulations

• Published in: Atmospheric Chemistry and Physics
• Main Authors: Orbe, Clara, Yang, Huang, Waugh, Darryn, Zeng, Guang, Morgenstern, Olaf, Kinnison, Douglas, Lamarque, Jean-Francois, Tilmes, Simone, Plummer, David, Scinocca, John, Josse, Béatrice, Marécal, Virginie, Jöckel, Patrick, Oman, Luke, Strahan, Susan, Deushi, Makoto, Tanaka, Taichu, Yoshida, Kohei, Akiyoshi, Hideharu, Yamashita, Yousuke, Stenke, Andreas, Revell, Laura, Sukhodolov, Timofei, Rozanov, Eugene, Pitari, Giovanni, Visioni, Daniele, Stone, Kane, Schofield, Robyn, Banerjee, Antara
• Other Authors: National Institute of Water and Atmospheric Research Lauder (NIWA), National Center for Atmospheric Research Boulder (NCAR), Atmospheric Chemistry Observations and Modeling Laboratory (ACOML), Environment and Climate Change Canada, Canadian Centre for Climate Modelling and Analysis (CCCma), Centre national de recherches météorologiques (CNRM), Météo France-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), DLR Institut für Physik der Atmosphäre (IPA), Deutsches Zentrum für Luft- und Raumfahrt Oberpfaffenhofen-Wessling (DLR), NASA Goddard Space Flight Center (GSFC), Meteorological Research Institute Tsukuba (MRI), Japan Meteorological Agency (JMA), National Institute for Environmental Studies (NIES), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Institute for Atmospheric and Climate Science Zürich (IAC), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology Zürich (ETH Zürich), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Physikalisch-Meteorologisches Observatorium Davos/World Radiation Center (PMOD/WRC), University of L'Aquila Italy (UNIVAQ), Centre of Excellence CETEMPS, Università degli Studi dell'Aquila (UNIVAQ), Massachusetts Institute of Technology (MIT), ARC Centre of Excellence for Climate System Science, University of New South Wales Sydney (UNSW)-Australian Research Council Canberra (ARC)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2019
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph]; Arctic
• Online Access: https://hal.archives-ouvertes.fr/hal-02374585; https://hal.archives-ouvertes.fr/hal-02374585/document; https://hal.archives-ouvertes.fr/hal-02374585/file/OrbeetalACP2018.pdf; https://doi.org/10.5194/acp-18-7217-2018

International audience Understanding and modeling the large-scale transport of trace gases and aerosols is important for interpreting past (and projecting future) changes in atmospheric composition. Here we show that there are large differences in the global-scale atmospheric transport properties among the models participating in the IGAC SPARC Chemistry-Climate Model Initiative (CCMI). Specifically, we find up to 40 % differences in the transport timescales connecting the Northern Hemisphere (NH) midlatitude surface to the Arctic and to Southern Hemisphere high latitudes, where the mean age ranges between 1.7 and 2.6 years. We show that these differences are related to large differences in vertical transport among the simulations, in particular to differences in param-eterized convection over the oceans. While stronger convec-tion over NH midlatitudes is associated with slower transport to the Arctic, stronger convection in the tropics and sub-tropics is associated with faster interhemispheric transport. We also show that the differences among simulations constrained with fields derived from the same reanalysis products are as large as (and in some cases larger than) the differences among free-running simulations, most likely due to larger differences in parameterized convection. Our results indicate that care must be taken when using simulations constrained with analyzed winds to interpret the influence of meteorology on tropospheric composition.