Retrieving sources of fine aerosols from MODIS and AERONET observations by inverting GOCART model

The knowledge of the global distribution of tropospheric aerosols is important for studying effects of natural aerosols on global climate. Chemical transport models relying on assimilated meteorological fields and accounting for aerosol advection by winds and removal processes can simulate such distribution of atmospheric aerosols. However, the accuracy of global aerosol modeling is yet limited. The uncertainty in location and strength of the aerosol emission sources is a major factor limiting accuracy of global aerosol transport modeling. This paper describes an effort to retrieve global sources of fine mode aerosol from global satellite observations by inverting GOCART aerosol transport model. The method uses an adjoint operation to the aerosol transport model that allows performing inversion with original space (2 x 2.5 degrees) and time (20-60 minutes) resolution of GOCART model. The approach is illustrated by numerical tests and applied to the retrieval global aerosol sources (location and strength) from a combination of MODIS and AERONET observations