Cloud detection over desert regions using the 412 nanometer MODIS channel

A method is proposed to enhance the performance of automated cloud detection algorithms in the vicinity of desert regions. The approach uses data in MODIS Channel 8, which has a bandpass of 405-420 nanometers (nm) where a strong contrast exists between the more highly reflective clouds and lower reflective cloud-free desert regions. Special processing is required to exploit cloud signatures since the MODIS high (880) signal-to-noise- ratio (SNR) requirement in this band causes saturation. The value of 412 nm data is demonstrated in the analysis of a scene that contains clouds over the western part of the Sahara Desert and has airborne sand and dust extending over the eastern Atlantic Ocean.