Daily rainfall and Meteosat cold-cloud duration images of Namibia were analysed for January and December 1993 and January and February 1994 to investigate the use of area-average data for estimating daily rainfall. Moderate to good correlations were obtained for area means for large regions and for Namibia as a whole. Correlations were generally much better than for individual stations averaged over time periods of up to 10-days. Correlations were lower in December than in January and February suggesting that deeper (colder) clouds are needed at the beginning of the season to produce rain. No clear pattern of spatial variation in correlation was found but calibrating individual pixels might provide an alternative to averaging to produce reasonable rainfall estimates. Some doubt is thrown on the validity of using 10-day CCD for estimating pixel rainfall values in Namibia.
Tucker, M.R. Final Technical Report for Project R5981. Estimation of rainfall in Namibia from meteosat infra-red imagery. (1996) 22 pp.