Onset Variation of Northeast Monsoon and Successive Rainfall over Tamilnadu

Abstract

The onset of monsoon plays an important role in agriculture and economy. The northeast monsoon onset dates changes every year; the climatological monsoon onset date is 20th October. In this paper, we analysed the monsoon onset dates in relation to rainfall variations during 1971 to 2016. With respect to the onset dates there's a version of monsoon rainfall in monsoon months (OND) and also with the average seasonal rainfall. In this study period we identified that delayed onset resulted in rainfall deficit and early onset provided above average rainfall in most years, but some years the monsoon onset did not affect the rainfall pattern. As it's far widely known, the worldwide phenomena like El Nino/La Nina also affecting the delay or improve in the monsoon onset and also in subsequent rainfall. Detailed discussions approximately the onset dates and the outcomes rainfall in the course of the monsoon months are given.