நீரியல்: தற்போதைய ஆராய்ச்சி

Analysis of Climate Variability and Drought Frequency Events on Limpopo River Basin, South Africa

Abstract

Sintayehu Legesse Gebre and Yitea Sineshaw Getahun

This study has analyzed the climate variability and meteorological drought events over Limpopo River Basin. The Limpopo Basin is shared by four countries, Botswana, South Africa, Zimbabwe, and Mozambique. The total catchment is approximately 408,000 km2. The main governing factor for rainfall patterns in the basin is the movement of the Inter-tropical Convergence Zone (ITCZ). In this study the drought event has been analyzed using standardized precipitation index (SPI). The SPI quantifies the precipitation deficit for multiple time scales and reflects the impact of droughts on the availability of water resources. The long year`s daily average monthly precipitation for the whole area indicates that the precipitation is variable and there is no any clear trend. The relative percentage change of average monthly precipitation of the 1992-2001 compared to 1961-1991 period using WATCH Climate data of the River basin indicates that, a positive value increase in percentage change is observed for the whole months of the year. High magnitude deviation in maximum and minimum temperature in the month of July 2001 observed with respect to 1961-2000 period. 5.2 and 7.9 degree centigrade respectively. The long term SPI analysis indicates that there was an extended accumulated sever dry condition that is prolonged from 1991 up to 1992 over the basin. Generally, this study indicates that there is a frequent meteorological drought events and unpredictable climate variability in the basin. Therefore farmers should take a precaution to adjust their farming system and to overcome drought events for better agricultural productivity.