Relation between Cold Cloud Data, Ndvi and Mopane in Eastern Botswana

Studies on vegetation geographical distribution patterns are often associated with the causal factors such as rainfall, soils or temperature patterns. Reasonably accurate and reliable maps of the climatic and edaphic factors are not always readily available, and when they are, their usefulness in biogeographical investigations is constrained by the quality of the data. Variability of rainfall in Botswana is very high in both spatial and temporal terms, but reliable rainfall measurements are taken on only a few (14) existing meteorological stations countrywide. More efficient methods of data capture that provide a complete coverage of the country’s entire surface are therefore used to complement the existing point data. Meteosat Cold Cloud Duration (CCD) data were used as a surrogate for rainfall patterns. The reasoning behind the use of CCD data was based on the premise that rainfall is related to cloud cover. A relationship between the two is determined for Botswana using CCD data and existing rain gauge data. Patterns in vegetation primary production in a north to south direction in eastern Botswana (covering the mopane belt) were sought through the use of NOAA NDVI data. A relationship between CCD’s and rainfall justifies the use of CCD patterns in the search for matching patterns of the mopane distribution. Although results show no indications of a match between the southern limits of mopane and mean annual rainfall, there is a general trend of declining correlation southeastwards. This indicates that mopane responds to a declining rainfall gradient and hence the differences in mopane structural types from north to south. * Corresponding author.