Long range transport of South and East Asian anthropogenic aerosols counteracting Arctic warming

• Main Authors: Fadnavis, Suvarna, Sonbawne, Sunil M., Laakso, Anton, Ploeger, Felix, Rap, Alexandru, Heinold, Bernd, Sabin, T. P., Müller, Rolf
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Nature 2024
• Subjects: info:eu-repo/classification/ddc/530; Arctic
• Online Access: https://juser.fz-juelich.de/record/1028433; https://juser.fz-juelich.de/search?p=id:%22FZJ-2024-04614%22

The large-scale convection during the Asian summer monsoon plays an important role in the rapidtransport of boundary layer aerosols into the Asian summer monsoon anticyclone. Here, using thestate-of-the-art ECHAM6–HAMMOZ aerosol-chemistry-climate model, we show that these aerosolsare further transported to the Arctic along isentropic surfaces by the Brewer-Dobson-Circulation(BDC) during the monsoon season. Our model simulations show that East and South Asiananthropogenic emissions contribute significantly to the aerosol transported to the Arctic, whichcauses a higher negative net aerosol radiative forcing at the surface (dimming) of −0.09 ± 0.02 Wm −2and −0.07 ± 0.02 Wm −2 , respectively. Over the Arctic, the East Asian anthropogenic aerosols thatinclude large amounts of sulfate cause a seasonal mean net radiative forcing at the top of theatmosphere (TOA) of −0.003 ± 0.001Wm −2 and a surface cooling of −0.56 K while the black carbondominated aerosol from South Asia shows a positive TOA forcing of +0.004 ± 0.001Wm −2 with an onlyminor surface cooling of −0.043 K. Overall, the long-range transport of South Asian aerosols results ina notably warming throughout the atmospheric column but minimal temperature response at the Arcticsurface. Conversely, East Asian aerosols cool the troposphere and heat the lower stratosphere in theArctic. The Asian aerosol thus plays an ambivalent role, with the East Asian sources in particular havingthe potential to counteract the rapid rise in Arctic temperatures and the associated melting of snowand ice.