Changing Aerosol Transport to the Arctic from Present Day to the End of 21st Century

Abstract:

Arctic climate has changed rapidly during recent decades, including increased surface temperature, reduced sea ice and land snow, and altered atmospheric circulations. One contributor to this change is absorptive aerosols (black carbon, brown carbon and dust) which are transported to the polar region and darken the bright snow and ice surface. The Arctic aerosol distribution is governed by three factors: emission, transport and deposition processes. Hence, an outstanding question is how will the transport and deposition of these forcing agents change when climate changes. In this study, we use a modified version of Bulk Aerosol Module (BAM) embedded in Community Atmosphere Model version 4 (CAM4) to track aerosol tracers emitted from different locations and investigate their transport to, and deposition within the Arctic in present and future climate. Two experiments have been designed to separate the effects of aerosol transport and deposition. A preliminary result shows that the transport efficiency for aerosols emitted from East Asia will increase about 50% in future climate (end of 21st century under Representative Concentration Pathways 8.5, RCP8.5) compared to present. Further analysis will place this change within the context of shifting atmospheric dynamics in the mid-high latitude region.