A new cloud mask algorithm used in aerosol retrieval over land for Suo-NPP VIIRS

摘要

Launching in October 2011, the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument has been stable operating for more than 5 years on board the Suomi National Polar-orbiting Partnership (S-NPP) spacecraft. Some researchers indicated that its aerosol optical thickness (AOT) product had larger biases than MODIS over land. Although the VIIRS-AOT algorithm is based on MODIS Dark-Target algorithm, some differs exist, including cloud mask. In considering the algorithm independence and identification complexity, we develop a new quick cloud mask algorithm for aerosol retrieval. Based on the spatial variability test inherent from MODIS, we add a expand test to remove the pixels mixed with cloud or effected by neighboring pixels. The results illustrate that this new test can screen out the confident cloudy pixels that VIIRS algorithm regard as clear sky. Throughout hundreds test in different weather conditions, the algorithm perform well.