Natural and anthropogenic dust: From sources to radiative forcing derived from satellite data and GFDL climate model.

Large uncertainty related to the radiative forcing of anthropogenic dust still remains due to the difficulty to detect and attribute dust sources outside arid regions. A new global inventory of dust sources is derived from Aqua MODIS Deep Blue Level 2 spectral aerosol data, after evaluation with ground based AERONET sunphotometers data. The natural or anthropogenic origin of the sources is attributed from land use, land cover and hydrological datasets. Comparison with data from other instruments (e.g. TOMS, OMI, SEAWiFS, MODIS on Terra) show remarkable similarities over most natural sources. The regional differences are essentially related to the combination of drought and land use. Simulations of natural and anthropogenic dust with the NOAA-GFDL AM3 climate model allow to quantify their respective contribution to aerosol optical depth, absorption optical depth and radiative forcing.