Change point detection and trend analysis of rainfall and temperature series over the vellar river basin

Abstract

Rainfall and temperature have been extensively considered as an initial point toward the apprehension of climate change progressions, establishing one of the important constituents of the hydrological cycle. The purpose of the present study is to examine the variability of rainfall and temperature for better understanding of the hydrological environment of the river basin located in northern Tamil Nadu. Mann-Kendall and Sen’s slope tests were employed for monthly, seasonal, and annual temperatures, and also for annual maximum daily rainfall, seasonal, and annual rainfall statistics. A change point detection test was applied for annual maximum and minimum, mean temperature, and annual precipitation series. The results revealed that all the monthly, seasonal, and annual maximum, minimum, and mean temperatures have a significant greater rising trend. The magnitude of increasing trends in NEM (northeast monsoon) and SWM (southwest monsoon) are greater than that of summer and winter seasons for almost all the rain gauge stations. The maximum temperature and minimum temperature change points are identified in the years 1985 and 2001 and 1987 and 2013, respectively. From the mean annual temperature, it is seen that the change point is present in 1983-88 and 2000-04 at 100% confidence interval.