Impacts of Model Biases in Aerosol Distribution on Climate Simulation of the Western Pacific Warm Pool Region

Monday, May 12, 2014 - 07:00
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Global climate models have significant biases in the representation of aerosols and their radiative impacts. Here, we investigate the role of direct and semi-direct effects of aerosols in air-sea interactions over the Western Pacific warm pool region using the Community Atmosphere Model (CAM4). Climate model simulations of the region are plagued with biases in SST as well as precipitation. A comparison of vertically integrated aerosol optical depth and vertical aerosol profiles between observations, derived from Department of Energy (DOE) Atmospheric Radiation Measurement Program (ARM) sites and CALIPSO satellite data, and those computed by CAM4 coupled to a bulk aerosol model reveal significant model biases. Results of experiments conducted with the stand-alone CAM4 and CAM4 coupled to a slab ocean model (SOM) forced with corrected estimates of vertical distribution of aerosols over the region derived from satellite observations will be presented. Preliminary results suggest that correcting the distribution of aerosols could have a significant impact on the east-west zonal SST gradient over the region as well as precipitation by modulation of surface radiative as well as turbulent heat fluxes.