AVHRR data sets for determination of desert spatial extent

A programme of global arid and semi-arid land monitoring is currently underway at NASA/Goddard Space Flight Center using meteorological satellite data to detect possible climatic change as manifested by changes in arid and semi-arid land extent. This has resulted in the processing and interpretation of a large amount of satellite data from the NOAA-series of polar-orbiting satellites. Techniques are described and preliminary results presented for determination of the boundary between the Sahara Desert and the Sahel Zone of Africa using daily advanced very high resolution radiometer data from 1980–1992. Some of the techniques may be of interest to other researchers who are or will be using large multi-year data sets derived from coarse-resolution satellite data to investigate large-scale land surface questions.