Climate Impacts of CALIPSO-Guided Corrections to Black Carbon Aerosol Vertical Distributions in a Global Climate Model

AbstractWe alleviate the bias in the tropospheric vertical distribution of black carbon aerosols (BC) in the Community Atmosphere Model (CAM4) using the CloudAerosol and Infrared Pathfinder Satellite Observations (CALIPSO)derived vertical profiles. A suite of sensitivity experiments are conducted with 1x, 5x, and 10x the presentday model estimated BC concentration climatology, with (corrected, CC) and without (uncorrected, UC) CALIPSOcorrected BC vertical distribution. The globally averaged top of the atmosphere radiative flux perturbation of CC experiments is 850% smaller compared to uncorrected (UC) BC experiments largely due to an increase in lowlevel clouds. The global average surface temperature increases, the global average precipitation decreases, and the ITCZ moves northward with the increase in BC radiative forcing, irrespective of the vertical distribution of BC. Further, tropical expansion metrics for the poleward extent of the Northern Hemisphere Hadley cell (HC) indicate that simulated HC expansion is not sensitive to existing model biases in BC vertical distribution.

Climate Impacts of CALIPSO-Guided Corrections to Black Carbon Aerosol Vertical Distributions in a Global Climate Model Academic Article