Low clouds and fog along the South-Western African coast — Satellite-based retrieval and spatial patterns

The spatial and temporal patterns of fog and low clouds along the South-Western African coast are characterized based on an evaluation of Meteosat SEVIRI satellite data. A technique for the detection of fog/low clouds in the region is introduced, and validated using 1 year of CALIOP cloud lidar products, showing reliable performance. The frequency of fog and low cloud in the study area is analyzed by systematic application of the technique to all available Meteosat SEVIRI scenes from 2004 to 2009, for 7:00 UTC and 14:00 UTC. The highest frequencies are encountered in the area around Walvis Bay, with a peak in the summer months. Fog and low clouds clear by 14:00 UTC almost everywhere over land. Supplementary data are available at doi:10.1594/PANGAEA.755427.

Research Highlights
► This paper studies fog/low cloud frequency along the south-western African coast.
► A Meteosat-SEVIRI satellite retrieval of fog/low clouds is introduced.
► In a validation study with CALIPSO CALIOP products, good performance is found.
► A five-year study of frequencies reveals a fog/low cloud hot spot around Walvis Bay.
► The most pronounced occurrence of fog/low cloud is encountered in the summer months.