Transport and Direct Forcing of Anthropogenic Aerosols in the Arctic

Abstract:

Anthropogenic aerososls can be transported to the Arctic through a long distance, and impact on the local climate by affecting regional energy budget. Here we use GEOS-Chem chemical transport model to simulate the transport of aerosols to the Arctic from anthropogenic sources in Asia, Europe and America respectively, and use the RRTMG radiative transfer model to calculate the direct radiative forcing (DRF) caused by these aerosols. We obtain a negative DRF of -0.13Wm^{-2} in Arctic at the top of atmosphere (TOA), in which Asia and Europe anthropogenic aerosols each contributes more than 40 percent, reaching -0.057Wm^{-2} and -0.051Wm^{-2}, and may potentially cause considerable climate effect. Particularly, scattering aerosols, mainly sulfate (SO4) and absorbing aerosols, primarily black carbon (BC) from Asia respectively cause -0.041Wm^{-2} and +0.018Wm^{-2} DRF in the Arctic, whereas these aerosols from Europe cause -0.043Wm^{-2} and +0.008Wm^{-2} DRF respectively. Moreover, we find that anthropogenic aerosols from Asia are distributed more uniformly in the Arctic, and can reach the center where the Arctic ocean is located, indicating a likely stronger impact on Arctic sea ice.