Probability distribution of rainfall and climate variability in Karnataka’s dry zones: Agricultural implications

Climate change and climatic variability pose significant challenges to rain-fed agriculture in Karnataka, particularly in its dry zones. These regions are characterized by erratic rainfall, recurrent droughts, and high dependence on climate-sensitive crops. Understanding rainfall variability and its probability distribution is essential for developing adaptive strategies. This study analyzed annual rainfall data (1979-2023) across five major dry zones North Eastern Dry Zone (NEDZ), Northern Dry Zone (NDZ), Central Dry Zone (CDZ), Eastern Dry Zone (EDZ), and Southern Dry Zone (SDZ) using probability distribution models to identify variability patterns and assess climatic risks. Rainfall data were sourced from the Karnataka State Natural Disaster Monitoring Cell (KSNDMC) and NASA POWER datasets. Probability distribution fitting was carried out using parameters such as shape, scale, and location to capture the central tendency and variability of rainfall across zones. The results revealed distinct rainfall characteristics across the zones. The NEDZ and NDZ are the most drought-prone, with Weibull and Gamma distributions capturing their high variability. The CDZ shows moderate stability, with rainfall clustering around 500-600 mm, though extreme wet years occur. The EDZ is marked by high inter-annual variability, best explained by a lognormal distribution, while the SDZ displays relatively stable rainfall following a normal distribution but remains vulnerable to both droughts and surpluses. Overall, the findings highlight the critical need for zone-specific adaptive measures such as drought-tolerant crops, efficient irrigation systems, water harvesting, and climate-informed crop planning. Integrating rainfall probability models into agricultural decision-making can significantly enhance resilience and sustainability in Karnataka’s dryland agriculture.