Climate Variable of Precipitation variation and its Drought Condition on Thoothukudi District, Tamil Nadu, India

Abstract

Abstract Precipitation variation study is one of the most important studies for monitoring the drought condition on the earth's surface. Climate change leads to excessive drought throughout the world. The present study has assessed the rainfall variation and monitored the drought condition in Thoothukudi district, Tamil Nadu, India. In this study, annual average rainfall and seasonal rainfall were estimated for 30 years. Moreover, monthly rainfall variation was computed through Standard Deviation (SD) and Coefficient of Variation (CV) for three decades from 1990 to 2019 and monitored the drought condition. The Thoothukudi district’s annual average rainfall varies more or less from year to year. During 1990–2007, significant rainfall variation was observed. Afterward, the variation was higher, and in 2008, the annual average rainfall was extreme. Seasonally, a high amount of rainfall was reported in the NE monsoon among four seasons for 30 years. The seasonal rainfall variability was less from 1990 to 2011. After that, the variation increased up to extreme than the state seasonal average except for summer. In the SW monsoon, rainfall has increased slightly, but it is below the state seasonal average due to changes in monthly rainfall. The monthly mean rainfall was less in the first two decades, while the third decade has high mean rainfall and varied from year to year. The first two decadal, April, May, August, September, October, and November, have < 100% of CV for mean rainfall, while January, February, March, and June have > 100% of CV for mean rainfall. In III-decade, mean rainfall has > 100% of CV for all decadal months except November. The precipitation variability leads to drought, either scanty or extreme. The study area has experienced scanty drought in the SW monsoon all the decades due to the lack of rainfall. Generally, excessive rainfall is recorded in the NE monsoon in Tamil Nadu. During III decades, excess rainfall has been reported in Kayalpattinam, Tiruchendur, Kulasekarapattinam, and Santhankulam, whereas scanty to deficient drought in the other two decades.