Archive for the ‘Satellite measurements’ Category

Satellite imagingWe have finally completed our evaluation of various aerosol products derived from satellite observation. The figure above shows one of the many that we have produced in the course of this work. It is a comparison of the various satellite products against sunphotometer measurements considered as the truth. It clearly shows that all instruments or algorithms are not born equal for providing an accurate picture of the aerosol load in the atmosphere. The official products from the Parasol and MODIS missions clearly provide the best results. Whether the quality is sufficient may depend on the application. The quality is certainly sufficient to provide a fair spatial and temporal distribution of the atmospheric load. Similar statistical indicators from model are certainly not as good, which demonstrates that the satellite data can still be used to improve or constrain the models.

On the other hand, I was talking yesterday with a colleague who argued that the quality of the products is still very much insufficient to constrain the aerosol impact on the Earth radiation budget to less than a few tenths of a Watt per square meter. For such objectives, new spaceborne instruments are needed and my colleague was arguing for the forthcoming Glory mission to be launched next year (after many delays). I am not fully convinced that Glory will do very much better than current instruments, but it will certainly improve the characterization of atmospheric aerosols, despite its very limited swath (and therefore coverage).


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