The effects of shifts in rainfall pattern on rainfall characteristics in Tanzania

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Date

1999

Journal Title

Journal ISSN

Volume Title

Publisher

Sokoine University of Agriculture

Abstract

This study was conducted with the aim of establishing the existence of significant shifts or departures in rainfall pattern and the effect this may have on some important rainfall characteristics in different parts of the country. A sample of 21 stations from six major agro-ecological zones in Tanzania was used in the study. Start dates of the growing season in various parts of Tanzania are variable and to some extent symbolize rainfall variability. Hence in this study, shifts in rainfall pattern are assumed to be reflected in the departures of start dates of the growing season from the mean. The start dates of the growing season for the various agro-ecological zones were determined using a calibrated rainfall-based criterion. Calibration of the rainfallĀ­ based criterion was achieved through use of a water balance simulation model which resulted in different sets of parameter values for each of the six agro-ecological zones. Other rainfall characteristics were derived using INSTAT statistical package. Results show that all stations in the six agro-ecological zones experience shifts in the rainfall pattern. Significant negative correlations between start dates and length of the growing season exist in all the stations with uni-modal type of rains and those with bi-modal type but for the long rains only. In other words the earlier the rains start, the longer the growing season is expected to last and vice versa.

Description

Dissertation

Keywords

Shifts, Rainfall pattern, Rainfall characteristics

Citation