Aerosols at the poles: an AeroCom Phase II multi-model evaluation

• Published in: Atmospheric Chemistry and Physics
• Main Authors: Sand, Maria, Samset, Bjørn, Balkanski, Yves, Bauer, Susanne, Bellouin, Nicolas, Berntsen, Terje, Bian, Huisheng, Chin, Mian, Diehl, Thomas, Easter, Richard, Ghan, Steven, Iversen, Trond, Kirkevåg, Alf, Lamarque, Jean-Francois, Lin, Guangxing, Liu, Xiaohong, Luo, Gan, Myhre, Gunnar, van Noije, Twan, Penner, Joyce, E, Schulz, Michael, Seland, Oyvind, Skeie, Ragnhild, Stier, Philip, Takemura, Toshihiko, Tsigaridis, Kostas, Yu, Fangqun, Zhang, Kai, Zhang, Hua
• Other Authors: Center for International Climate and Environmental Research Oslo (CICERO), University of Oslo (UiO), Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Modelling the Earth Response to Multiple Anthropogenic Interactions and Dynamics (MERMAID), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Department of Meteorology Reading, University of Reading (UOR), Joint Center for Earth Systems Technology Baltimore (JCET), NASA Goddard Space Flight Center (GSFC)-University of Maryland Baltimore County (UMBC), University of Maryland System-University of Maryland System, NASA Goddard Space Flight Center (GSFC), JRC Institute for Environment and Sustainability (IES), European Commission - Joint Research Centre Ispra (JRC), Pacific Northwest National Laboratory (PNNL), Atmospheric Chemistry Observations and Modeling Laboratory (ACOML), National Center for Atmospheric Research Boulder (NCAR), Norwegian Meteorological Institute Oslo (MET), Department of Physics Oxford, University of Oxford, Kyushu University, Center for Climate Systems Research New York (CCSR), Columbia University New York, Atmospheric Sciences Research Center (ASRC), University at Albany SUNY, State University of New York (SUNY)-State University of New York (SUNY)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2017
• Subjects: [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph]; [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; Antarc*; Antarctic; black carbon
• Online Access: https://hal.science/hal-02875476; https://hal.science/hal-02875476/document; https://hal.science/hal-02875476/file/Sand2017_ACP.pdf; https://doi.org/10.5194/acp-17-12197-2017

International audience Atmospheric aerosols from anthropogenic and natural sources reach the polar regions through long-range transport and affect the local radiation balance. Such transport is, however, poorly constrained in present-day global climate models, and few multi-model evaluations of polar an-thropogenic aerosol radiative forcing exist. Here we compare the aerosol optical depth (AOD) at 550 nm from simulations with 16 global aerosol models from the AeroCom Phase II model intercomparison project with available observations at both poles. We show that the annual mean multi-model median is representative of the observations in Arctic, but that the intermodel spread is large. We also document the geographical distribution and seasonal cycle of the AOD for the individual aerosol species: black carbon (BC) from fossil fuel and biomass burning, sulfate, organic aerosols (OAs), dust, and sea-salt. For a subset of models that represent nitrate and secondary organic aerosols (SOAs), we document the role of these aerosols at high latitudes. The seasonal dependence of natural and anthropogenic aerosols differs with natural aerosols peaking in winter (sea-salt) and spring (dust), whereas AOD from anthropogenic aerosols peaks in late spring and summer. The models produce a median annual mean AOD of 0.07 in the Arctic (de-fined here as north of 60 • N). The models also predict a noteworthy aerosol transport to the Antarctic (south of 70 • S) with a resulting AOD varying between 0.01 and 0.02. The Published by Copernicus Publications on behalf of the European Geosciences Union. 12198 M. Sand et al.: Aerosols at the poles: an AeroCom Phase II multi-model evaluation models have estimated the shortwave anthropogenic radia-tive forcing contributions to the direct aerosol effect (DAE) associated with BC and OA from fossil fuel and biofuel (FF), sulfate, SOAs, nitrate, and biomass burning from BC and OA emissions combined. The Arctic modelled annual mean DAE is slightly negative (−0.12 W m −2), dominated by a positive BC ...