Precipitation analysis for the East and South districts of Sikkim, India

Abstract

This study emphasizes the rainfall analysis in the state of Sikkim located in the north east region of India, which covers up an area of 7097 km2. The rainfall analysis of the two districts East Sikkim and South Sikkim for a period of 118 years (1901-2018) are computed. Various tests depicting the trends, homogeneity, slope and statistical data reveals the monthly, seasonally and annual rainfall pattern in these districts of Sikkim. For the annual rainfall, the coefficient of variance varies from 13% to 19% whereas the coefficient of variance for seasonal rainfall varies from 14% to 81% which indicates that seasonal variability is more than the annual variability. Southwest monsoon contributes 79% to the annual rainfall followed by pre-monsoon which contributes 14% to the annual rainfall. The trend analysis depicts an insignificant increasing trend annually but a significantly decreasing trend for the south west monsoon with a negative slope justifying the downward trend. The homogeneity test points out the specific year the trend of the rainfall begins which was found to be in the year 1955.