Study of trend of rainfall data: A case study of Koraiyar basin, Tamil Nadu

1772-1778Rainfall is an vital hydro-climatic element at the helm of that heads the hydrological cycle and water availability in a specific region. In current years, significant deviances have been observed in rainfall patterns on a global as well as local scale. Several analyses have established that any study of hydro-climatic variables must be handled and executed on different micro-scales rather than regional scale because the trends and their effects may differ widely from station to station. In the current investigative study, the urban rainfall variation in the Koraiyar basin between the years 1975-2010 is examined to study the trend of precipitation. The non-parametric test is used in this study because the data outliers can be avoided easily. The Mann-Kendall (M-K) method is adopted to analyze the trend, and Sen’s slope is used to estimate the linear trend. To detect the change in trends, the CUSUM test is applied. The coefficient of variance (CV) is applied for variability analysis. From the analysis, it is noted that there is an unpredictable increasing and decreasing trend in the yearly and periodic rainfall patterns in the basin