Precipitation trends analysis of North Karnataka for 1960–2018 using GIS modelling

Climate change, burgeoning population, rapid urbanization, and over-exploited use of natural resources—such alarming situations require immediate interventions to plan and manage water resources sustainably. In present study, the study area is comprised of eight districts covering five different agro-climatic zones of North Karnataka. The objective of this study is to investigate the spatial distribution of the long-term precipitation concentration index (PCI). In pursuit of these objectives, the methodology employed in this research involves utilizing the Mann–Kendall test and Sen’s slope estimator to identify trends in long-term rainfall patterns. The annual precipitation concentration index and seasonal precipitation concentration index were calculated based on Karnataka State Natural Disaster Mitigation Centre meteorological data. The estimation of rainfall distribution is compared in Regular intervals of time for different time series (1961–1989) and (1990–2018). The results show that the annual PCI values vary between 14 and 52. These values indicate the precipitation at annual scale is more of moderately irregular except in zone 9 which is a wet (hilly) zone dominated by a dry period of 8 months in a year. The findings of the study reveal significant variations in the distribution of precipitation across the North Interior Zones of Karnataka. The analysis of the Annual Precipitation Concentration Index highlights the localized variations in rainfall, reflecting the diverse climatic conditions within the study area. The trend analysis of the rainfall data indicates long-term changes in precipitation patterns, which could have implications for water resource management.