Spatiotemporal Rainfall Variability and Trend Analysis of Shimsha River Basin, India

Abstract

The current study aims to determine the variability and trend in rainfall data. From 1989 to 2018, daily rainfall data was gathered for the Shimsha basin, a sub-basin of the Cauvery basin in Karnataka, India, and aggregated into annual, seasonal, and monthly rainfall totals as well as the number of rainy days. In this study, the time series are subjected to statistical methods to examine rainfall variability and trend. The mean, standard deviation, skewness, kurtosis, coefficient of variation (CV), and Standardized Anomaly Index (SAI) are all used in the preliminary and variability analysis. To understand the rainfall distribution characteristics, Kurtosis and skewness were used. To identify homogenous and serially independent series, homogeneity and serial correlation tests were used. Mann-Kendall (MK) and Spearman's rank correlation (SRC) tests were performed to identify the trend in the homogenous and serially independent series. Sen's slope (SS) technique is applied to quantify the amount of the trend, and the Sequential Mann-Kendall (SQMK) test was used to assess the trend change point. The statistical tests indicated in this work were performed using open-source R packages such as "trend," "modifiedmk" and "trendchange". The study area's average rainfall was 801.86 mm, and CV ranges from 43.3% to 22.27%. The basin receives the highest rainfall in southwest monsoon season (SWM) followed by post-monsoon, summer, and winter seasons, respectively.Out of 162 series, 11-time series were found to be non-homogeneous and were omitted. Then out of 151 homogeneous series, 21 series showed a significant increasing trend while 99 and 31 series showed a little rising and declining trend, respectively. The study's results will help in water resource management, agricultural planning and socioeconomic development in the area.

Spatiotemporal analysis and predicting rainfall trends in a tropical monsoon-dominated country using MAKESENS and machine learning techniques

“…According to this phenomenon, Monsson rains appear to occur earlier than expected in a calendar year. Identical changes in monsoon rainfall patterns were also observed in neighboring countries 16 , 86 , 133 . This fluctuation is evident in the changing rainfall pattern over the year, promoting the meteorological drought 134 .…”

“…There are many different temporal and geographical scales at which precipitation variability as a component of climate change occurs. Worldwide studies have shown increasing rainfall variability on a global scale 14 , 15 , and the Indian Sub-continent, including India 16 and Pakistan 17 , 18 . Many studies 19 – 21 have examined the spatiotemporal patterns of rainfall in climatic zones across the world 22 – 25 .…”

The significance of morphometric analysis of Shimsha River, Karnataka, India to understand the hydrological and morphological characteristics

“…The mean rainfall varies from 600 and 800 mm in semiarid areas. The major rainfall seasons in the area are south‐west monsoon (Bharath, Maddamsetty, Manjunatha, et al, 2023; Bharath, Maddamsetty, & Uttam, 2023).…”

“…Morphometry is the measurement and mathematical analysis of the configuration of the land surface, shape, and dimensions of its landforms (Clarke, 1966; Pareta & Pareta, 2011; Strahler, 1964). The estimations of morphometric parameters like stream order, stream length, bifurcation ratio, channel length, relative relief, drainage density, stream frequency, form factor, shape factor, texture ratio, elongation ratio, circularity ratio, and compactness constant are dependent on the formulae proposed by (Bharath, Maddamsetty, Manjunatha, et al, 2023; Bharath, Maddamsetty, & Uttam, 2023; Gautam et al, 2023; Gautam et al, 2020; Horton, 1945; Kumar et al, 2018; Miller, 1953; Schumm, 1956; Strahler, 1964). The gradient of drainage and slope of the fluvial systems is the important component of morphometric characteristics of the river basin (Nautiyal, 1964; Strahler, 1964).…”

“…The Shimsha River is a significant river in Peninsular India, primarily flowing through Karnataka. It is a left tributary of the Cauvery River (Bharath, Maddamsetty, Manjunatha, et al, 2023; Bharath, Maddamsetty, & Uttam, 2023). In this study, river morphometry plays an important role in the modern perspective by providing insights into various aspects of river systems and their management such as flow characteristics, flood risk assessment, floodplain mapping, erosion control, habitat assessment, sediment dynamics, land use planning, and water resource management.…”