Spatiotemporal Analysis of Rainfall and Temperature Over Pennar River Basin, India

Abstract

The purpose of the current study is to identify the temporal trends in rainfall and temperature trends in Peninsular India's Pennar Basin. Rainfall data were taken for a period of 1971–2020 (50 years) at 0.25º × 0.25º and temperature data were taken for a period of 1996–2020 (25 years) at 1º × 1º resolution, respectively, from IMD, Pune, and are analyzed at annual, monsoon seasonal and daily peak time scales. Trends in the rainfall and temperature are detected by non-parametric modified Mann–Kendall (MMK) and Spearman’s correlation ratio (SCR) tests, and their change in magnitude with time is reported using Sen’s slope estimator. A graphical method ‘Innovative Trend analysis’ is also used to obtain the nature of the pattern for the respective time series data at different time scales. The annual rainfall data have shown a significantly positive trend across most of the grids. The monsoon seasonal rainfall data have shown a mix of both positive and negative trends, while the daily peak rainfall data have shown more of a negative trend. The maximum and minimum temperature data in all the time scales show either negative trend or no trend. These trends have been confirmed by non-parametric tests and a graphical method used in the study.