Direct Effect of Aerosol on Subseasonal-to-Seasonal Prediction Using FIM-Chem-iHYCOM Coupled Model

The direct effect of aerosol on subseasonal to seasonal (s2s) prediction is investigated using a global coupled atmosphere, chemistry and ocean model of FIM-Chem-iHYCOM. The online chemistry includes a simple suite with bulk aerosols only. The sources and sinks for aerosols, fire and anthropogenic emissions are prescribed during the model integration. The resulting aerosol optical depths from the model are shown to be in good agreement with observations. We compare the model sensitivity on surface radiation, cloudiness and precipitation with various aerosol emissions at different seasons from multi-year experiments. Additional emphasis of this work is on the effect of aerosols from biomass burning emissions at the s2s time scale.