Towards an improved representation of carbonaceous aerosols over the Indian monsoon region in a regional climate model: RegCM

[摘要] Mitigation of carbonaceous aerosol emissions is expected toprovide climate and health co-benefits. The accurate representation ofcarbonaceous aerosols in climate models is critical for reducinguncertainties in their climate feedback. In this regard, emission fluxes andaerosol life cycle processes are the two primary sources of uncertainties.Here, we demonstrate that the incorporation of a dynamic ageing scheme and emissionestimates that are updated for the local sources improves the representationof carbonaceous aerosols over the Indian monsoon region in a regionalclimate model, RegCM, compared with its default configuration. The respective mean black carbon (BC) and organic carbon(OC) surface concentrations in 2010 are estimated to be 4.25 and10.35  µ g m −3 over the Indo-Gangetic Plain (IGP) in the augmentedmodel. The BC column burden over the polluted IGP is found to be2.47 mg m −2 , 69.95 % higher than in the default model configuration and muchcloser to available observations. The anthropogenic aerosol optical depth (AOD) increases by morethan 19 % over the IGP due to the model enhancement, also leading to abetter agreement with observed AOD. The respective top-of-the-atmosphere, surface, andatmospheric anthropogenic aerosol short-wave radiative forcing are estimatedat −0.3 , −9.3 , and 9.0 W m −2 over the IGP and −0.89 , −5.33 , and 4.44 W m −2 over Peninsular India (PI). Ourresults suggest that the combined effect of two modifications leads tomaximum improvements in the model performance in regions where emissions play adominant role.

[学科分类] 土木及结构工程学