Journal of Kenya Meteorological Society
Cloud Cover Estimation over Selected Locations in East Africa Using Satellite Derived Reflectivity Data.
Nzioka J. Muthama*, K. H. Kai**, G. O. Ouma*, J. K. Ng'ang'a* and F. J. Opijah*
*Department of Meteorology, University of Nairobi, **Tanzania Meteorological Agency
Nzioka J. Muthama
Department of Meteorology, University of Nairobi
P.O. Box 30197 – 00100 Nairobi
(Manuscript received 16 November 2007, in final form 27 February 2008)
The study aimed at improving the estimation of cloudiness over East Africa through establishment of the relationship between observed cloud cover and the satellite derived reflectivity. Two types of data were used, namely: remotely sensed data and the ground cloud observation for the stations over the selected area of East African region covering from 0.11oN to 5.47oS and 32.33oE to 39.15oE. The stations considered were Nairobi and Mombasa for Kenya, Dar-esSalaam and Kilimanjaro for Tanzania, and Kampala, Makerere and Kasese for Uganda. The remotely sensed data were obtained from one channel of the Total Ozone Mapping Spectrum (TOMS) satellite. Correlation analysis indicated that there is a significant relationship between ground-based cloud cover and satellite-derived reflectivity. The relationship seemed to be influenced by the prevailing mesoscale features prevalent in the specific areas. Based on these correlation analysis results, it may be concluded that satellite-derived reflectivity can represent the observed cloud cover, and consequently models can be designed to estimate the in-situ cloud observations over areas lacking ground-based cloud observations.