Changing Rainfall Regimes in India: A District Level Appraisal

Background The south west monsoon plays crucial role in shaping the agriculture and economy of India, where majority is still dependent of agriculture for their livelihood. Changing spatio-temporal distribution of the rainfall affects both food and water security of the region which is further exacerbated by the climate change. So, this study aims to assess the changing trend and pattern of the rainfall at district level in India. Data and Method The present study utilized the daily total rainfall data acquired at district level from the Indian Meteorological Department (IMD) for the time period of 1960 to 2023. Further acquired rainfall data was processed and subjected to statistical analysis. The PBIAS is applied for assessing rainfall change between last two climatic cycle. The coefficient of variation (CV) is estimated for testing rainfall variability and, Mann-Kendall test & Sen’s slope estimator, to analyze trend and pattern in monthly, seasonal and annual rainfall. Result A decreased rainfall has been recorded across the districts of the Ganga-Brahmaputra River valley, while increased rainfall has been found in the districts of coastal region including the state of Rajasthan, Jammu & Kashmir, and Meghalaya during monsoon season. Increased variability was found across more districts during July and August while trend analysis result indicates some districts from northern plain are experiencing significant declining rainfall. These changes in rainfall were mostly occurs during the decade of 1980s to 2000. Conclusion Decreasing rainfall in the northern plain of India can deteriorate the existing condition of food security because of its huge population. Similarly increasing rainfall in districts of arid region of India provide new opportunities. Specific custom-made polices are needed to address the changing rainfall pattern for the overall socio-economic wellbeing.