The Rainfall-Altitude Relation and Its Ecological Significance in Kenya

Thumbnail Image
Trapnell C. G.
Journal Title
Journal ISSN
Volume Title
The vegetation types of southern Kenya have been found to fall into three separable climatic series in the range between higher and moister and lower and drier conditions. The lines of _ division between these sequences have been drawn on a small-scale map. Their effect is to show that southern Kenya is divisible into three main sectors, referred to as the Western Decline, the Rift Highlands, and the Eastern Decline. This three-fold division is found to be associated with differing combinations of rainfall and altitude, expressed in terms of the number of inches of rainfall per thousand feet of altitude. Computations for 550 stations show that the Eastern and Western Declines enjoy high rainfall-altitude ratios, falling generally between 6 and 16 inches per thousand feet, whereas the greater part of the Rift Highlands sector has only 3 to 6 inches per thousand feet. Exceptions in the Baringo-Elgeyo rift region are commented on. The lines of division otherwise correspond remarkably closely to the 6 inches isogram. This relationship may be regarded as a first approximation to one of rainfall and temperature. Its significance is discussed with reference to temperature-altitude relations and to its general bearing on bioclimatic interpretation in Kenya.
East African Agricultural And Forestry Journal, XXV (4), p. 207-213