Assessment of long-term variability in rainfall trends over Damodar River Basin, India

Abstract

Understanding rainfall is vital for analyzing river basins as it is an integral part of its hydrological cycle. This paper has focused on examining annual and seasonal precipitation variation from the year 1901 to 2021 along with maximum and minimum temperatures from the year 1951 to 2021 within the Damodar River Basin. Serial dependence is determined initially by calculating lag-1 autocorrelation coefficient on the time series dataset before removing impacts of serial correlation by applying pre-whiteness processing ahead of conducting Mann–Kendall tests. The non-parametric Mann–Kendall test alongside Sen's slope estimator have helped ascertain extreme precipitation and temperature presence and size magnitudes while Sequential Mann–Kendall (SQMK) tests have aided us in detecting sudden change within these trends. The average annual maximum and minimum temperatures have exhibited declining and increasing trends, according to a careful review of the data, the maximum and minimum temperature during the monsoon have shown an increasing tendency. The annual and monsoon rainfall are both trending downward by – 0.582 mm/year and – 0.355 mm/year, respectively. While the annual minimum temperature showed an increasing trend (0.0028 °C), the annual maximum temperature for the observed time showed a low warming or falling trend of (– 0.0019 °C). At a 5% level of significance, the annual minimum temperature result was found to be statistically significant, but the annual maximum temperature trend result was not. The SQMK approach demonstrates periodic trend fluctuation, which is particularly apparent during the pre-monsoon and monsoon season. This investigation makes use of a thorough examination of the shifting trends in rainfall patterns seen in hydro-meteorological data collected within the Damodar River Basin. The results of this study have a great deal of promise for use in managing water resources and promoting sustainable agriculture in the basin's environs. Graphical Abstract: [Figure not available: see fulltext.] © 2023, The Author(s), under exclusive licence to Springer Nature Switzerland AG.