Consistency of Aerosol Optical Depth from different Aerosol retrieval algorithms and instruments

Aerosols affect climate in several ways. Aerosols together with clouds contribute the largest uncertainties to the Earth’s radiative forcing estimates, according to IPCC. Consequently, accurate retrieval of the Aerosol Optical Depth (AOD) from satellite measurements is important to improve the knowledge about aerosols in the global atmosphere and the associated influence of natural and anthropogenic events on the amount of aerosols. Since the retrieval of AOD is typically under-determined it needs assumptions concerning aerosol properties and the surface of the Earth – consequently, there are several different algorithms. We analyse data from the Copernicus Climate Change Service of retrieved AOD with Dual-View Instruments (Along Track Scanning Radiometer 2 (ATSR2), Advanced Along Track Scanning Radiometer (AATSR), Sea and Land Surface Temperature Radiometer (SLSTR)) and the Infrared Atmospheric Sounding Interferometer (IASI) for the retrieval of Dust AOD.

For reliable conclusions the results of these algorithms and of different instruments should be consistent. When looking at different regions we observe, that the consistency between different algorithms differs depending on the type of surface or the geographical location. Looking at fractions of AOD measured by different instruments, we find inconsistencies over deserts and part of the oceans with much sea salt AOD. Apart from that, the results are consistent.

Based on these results, we plan to develop a new retrieval ​​combining the different instruments in order to use their respective advantages and to reduce the errors. In a first step data from SLSTR, IASI and additionally GOME-2 will be combined.