DP - 2015年12月12日，TA - 当前世界环境PG - 928-933 VI - 30 IP - 33 4099 - www.a-i-l-s-a.com/article/858/ 4100 - www.a-i-l-s-a.com/article/858/ ab - 干旱是影响自然资源和环境的长期水资源稀缺性最广泛的水力气象模式。然而，它具有从一个区域到另一个区域的显着不同的特征。泰米尔纳德邦从包括干旱在内的各种灾难中痛苦。通常从长期平均值的降雨偏差继续是用于干旱强度评估的广泛采用的指标。该指标的应用受到其对平均值的固有性质的影响。因此，克服了这些限制的标准化程序成为基本需要。此外，近年来降雨的稳定性是不稳定的，因此了解多年来降雨量的稳定性降水比（PR）。进一步了解泰米尔纳德南部南部地区的干旱气候，使用标准化降水指数（SPI）。PR研究了三十年（1981-2010）覆盖了七个地点。 In most of the locations the rainfall was stable during 1981-90 and thereafter a gradual decline in stability was noticed confirming the weather extremes in the recent decade. SPI had an annual range from +2.69 to -4.94 while Monsoon period had +2.41 to -3.43 and +2.69 to -3.14 respectively for Southwest and Northeast monsoon seasons. As per SPI index, Southern zone is prone to moderate drought followed by severe and extreme drought category. Among the periods studied (Annual, SWM and NEM) number of moderate drought occurrences had no much variation while in severe and extreme drought category, variations could be observed. In particular, during NEM period there was almost no occurrence of extreme drought.