Polar sea-salt aerosols in CMIP6 models

• Main Authors: Lapere, Rémy, Thomas, Jennie, Marelle, Louis, Ekman, Annica, Frey, Markus, Lund, Marianne, Makkonen, Risto, Ranjithkumar, Ananth, Salter, Matthew, Samset, Bjørn, Schulz, Michael, Sogacheva, Larisa, Yang, Xin, Zieger, Paul
• Other Authors: Institut des Géosciences de l’Environnement (IGE), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), TROPO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Meteorology Stockholm (MISU), Stockholm University, Bolin Centre for Climate Research, British Antarctic Survey (BAS), Natural Environment Research Council (NERC), Center for International Climate and Environmental Research Oslo (CICERO), University of Oslo (UiO), Kuopio Unit FMI, Finnish Meteorological Institute (FMI), Department of Environmental Science and Analytical Chemistry Stockholm (ACES), Norwegian Meteorological Institute Oslo (MET)
• Format: Conference Object
• Language: English
• Published: HAL CCSD 2023
• Subjects: [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography; [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph]; Antarctic; Antarc*
• Online Access: https://insu.hal.science/insu-04031230; https://doi.org/10.5194/egusphere-egu23-12728

International audience We present an inter-comparison of simulated sea-salt aerosols (SSA) in CMIP6 models, including an evaluation against station observations in the Artic and Antarctic regions and satellite data. Drivers of model diversity are investigated. Historical and future trends are also explored and connected to their driving mechanisms. Additionally, the sensitivity of the polar radiative budget to SSA in CMIP6 models is quantified and put in relation to present-day uncertainties and future trends. Comparisons suggest (i) a large inter-model spread in SSA surface concentrations mostly driven by the diversity in source functions, (ii) an important overestimation of SSA surface concentrations compared to measurement stations but reasonable agreement with optical depth from satellite data, (iii) difficulties in properly capturing the annual cycle of SSA at both poles, particularly at higher latitude. A generally increasing trend in SSA concentrations is found in CMIP6 over the last decades and in future scenarios. CMIP6 models show that SSA contribute to cooling the poles significantly, implying possible uncertainties of several W/m2 in the present-day polar radiative budget.