Browsing by Author "maglo, Harrison A"
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Item Investigations of meteorological drought and rainfall oscillations in Tanzania(University of Dar es Salaam, 1997) maglo, Harrison AOne major phase of the hydrological cycle namely; precipitation (which in most parts of Africa is equivalent to rainfall), was studied in Tanzania on the basis of its deficiency below a specific demand level, oscillations and onset. GIS, which is a recently emerged field of applied science and technology is applied to analyse rainfall data to define drought over an area. Rainfall data from 440 stations from Tanzania is used in defining drought event indicators which are later used to delineate the regions of Tanzania into drought-prone zones. The major approach in the study is the identification of four drought-prone zones through the overlaying of a digitized map of Tanzania with drought event indicator maps obtained from rainfall-deficiency analysis. The results show that areas around the north-central regions of Tanzania (Dodoma, Singinda, Tabora, etc.) are the most severely prone to drought. A mathematical model for the duration and severity of drought based on rainfall deficiency analysis is equally presented. Some other methods of defining drought are also reviewed. Though their application is not direct they could, however, serve as guides in earmarking drought occurrences in any place when appropriate and meaningful interpretations are made. As an added guide, autocorrelation and spectral analysis techniques were used to reveal any existing cyclic or periodic patterns in the rainfall series. Distinct peaks in the spectrum of some stations were observed whereas others do not show anything significant. Some work on the onset, cessation, duration and the probability of failure of rainfall was also undertaken to provide, on the average, an essential guide to the farming community.