Regional distribution of absorbing efficiency of dust aerosols over India and adjacent continents inferred using satellite remote sensing

The investigations as part of ACE-Asia have demonstrated that dust we observe may not be just dust, but it may be dust mixed with other aerosols. Consequently dust radiative forcing ( even its sign) has a large uncertainty due to the lack of database on complex spatial and temporal pattern of dust radiative properties. To accurately predict the impact of dust aerosols on climate the spatial and temporal distribution of dust radiative properties is essential. Here, we propose a method to infer regional distribution of dust radiative properties using satellite remote sensing ( infrared and visible/UV channels) and demonstrate its application. Our studies show that dust in desert areas is low absorbing type while those transported to other locations having anthropogenic activities are significantly more absorbing than pure dust aerosols. This provides a strong evidence for the possible mixing of dust aerosols with other aerosols such as black carbon.