Retrieval of Marine Stratus Cloud Droplet Size from NOAA–AVHRR Nighttime Imagery

A method for retrieval of the droplet radius and temperature of oceanic stratocumulus is presented. It is based on night imagery obtained from the infrared channels of NOAA–AVHRR and an atmospheric radiative transfer model that makes use of the discrete ordinate method DISORT. It uses the observed satellite brightness temperature differences (BTD) between channels 4 and 5 to obtain the cloud temperature and between channels 3 and 4 to extract the effective radius of the cloud droplets. We also studied the peculiarities of the method, taking into account the behavior of the single scattering parameters, deduced from Mie theory, with droplet size. Results obtained are compared with in situ data collected at the Canary Islands (Spain) during summer 1996.