当前世界环境

The present study attempted to find out the relation between rainfall variability, trend and distribution in Dindigul district of Amaravathi basin for groundwater management. A detailed analysis of monthly, seasonal and spatial variation of rainfall (1971-2014) for the study area had carried out. The normal annual rainfall of the district varies from 700 to 1600 mm. The north east monsoon contributed the maximum rainfall of 439mm (50%), followed by South-west monsoon which contributed 254 mm (29%), summer which contributed 147 mm (16.8%) and winter contributed the minimum rainfall of 26.8 mm (2.8%).A high value of CV had observed in all the stations, which indicate the greater rainfall variability, and more chances of occurrence of drought. Higher variability of coefficient of variation was observed in central part of the district.Theresult of MMK z-test at 1% level indicates that the majority of stations showed non-significant trend in annual, summer and monsoon season of rainfall. Out of the 13 stations studied in the district, annual rainfall of only one station (Kuthiraiyar) showed significant decreasing trend in annual rainfall (-3.05 mm/year) and five stations recorded the significant decreasing trend in rainy days during southwest monsoon. Chatrapatti and Natham stations recorded the significant increasing trend during north east monsoon and Virupatchi station recorded the decreasing trend.