Arctic Oscillation Responses to Black Carbon Aerosols Emitted from Major Regions

Abstract

AbstractThe responses of the Arctic Oscillation (AO) to global black carbon (BC) and BC emitted from major regions were compared using the atmospheric general circulation model Geophysical Fluid Dynamics Laboratory (GFDL) atmospheric general circulation model (AGCM) Atmospheric Model version 2.1 (AM2.1). The results indicated that global BC could induce posi-tive-phase AO responses, characterized by negative responses over the polar cap on 500 hPa height fields, and zonal mean sea level pressure (SLP) decreasing while zonal wind increasing at 60°, with the opposite responses over midlatitudes. The AO indices distribution also shifted towards positive values. East Asian BC had similar impacts to that of global BC, while the responses to European BC were of opposite sign. South Asian BC and North American BC did not affect the AO significantly. Based on a simple linear assumption, we roughly estimated that the global BC emission increase could explain approximately 5% of the observed positive AO trend of +0...