ABSTRACT
This chapter considers some of the statistical terms which have been used to describe rainfall in the Sahel. The literature concerned with Sahelian droughts is, nevertheless, replete with references to particularly dry years as being abnormal or anomalous. The standard deviation or coefficient of variation is generally relied upon as the appropriate measure of variability of rainfall in studies of the Sahel. Measuring the variability of Sahelian rainfall is further complicated by the question of whether or not there are trends or cycles or other evidence of climatic change in the data. Desertification is the result of either the vagaries of weather and climate or the mismanagement of the land or, as in most cases, some combination of both. A major step toward combatting deterioration, and ultimately desertification, in the Sahel and in similar ecosystems would be the determination of an ecologically realistic carrying capacity for the rangelands.
