Unravelling the dynamics of rainfall patterns in Bihar, India: A comprehensive spatiotemporal analysis

Abstract

Climate change, resulting from anthropogenic activities, poses a substantial global challenge, inducing discernible shifts in hydro-climatic variables such as temperature, precipitation, river discharge, and extreme weather events. Its implications extend to India’s natural resources and agricultural sectors. This research rigorously examines the long-term spatial and temporal changes in rainfall patterns in Bihar, India, utilising high-resolution daily rainfall gridded data from the India Meteorological Department, which includes data from a total of 133 grid points. Coefficient variation analysis reveals low monsoon and annual rainfall variability but substantial variations in the pre-monsoon, post-monsoon, and winter seasons, indicating pronounced changes in Bihar’s precipitation patterns. Trend analysis offers nuanced insights, using Modified Mann–Kendall (MMK) and Innovative Trend Analysis (ITA). Pre-monsoon rainfall exhibits a statistically significant increasing trend (Z = 3.252), with an annual increment of 0.748 mm. In contrast, a persistent decline characterises monsoon (Z =  − 0.598), post-monsoon (Z =  − 0.112), winter (Z =  − 0.297), and annual (Z =  − 0.219) precipitation patterns over 72 years. Change point analysis identifies pivotal shifts in 1982 (annual), 2007 (monsoon), 2012 (pre-monsoon), 1954 (post-monsoon), and 1997 (winter). Spatial–temporal analysis indicates regional shifts post-1982, with maximum annual rainfall significantly decreasing from 2769 to 2453 mm. The findings underscore the necessity to reassess water resource management, employing diverse analytical approaches for robust climate adaptation, resource planning, and disaster preparedness. This research enhances the scientific understanding of long-term climate dynamics, offering insights into sustainable practices in Bihar’s agriculture and environmental ecosystems.