Block-level long-term rainfall variability using trend analysis in a state of central India

Rainfall is the key weather element which regulates the hydrological cycle, availability of water resources and crop production. In this study, spatial and temporal variability of rainfall has been investigated on seasonal and annual time scales of the 149 blocks of Chhattisgarh State using 120 years (1901–2020) of rainfall data. Non-parametric, and Theil and Sen's slope estimator were used to identify possible trends and ascertain the variability in the magnitude. The results revealed that there exists a well-marked spatial variability in rainfall over Chhattisgarh on annual and seasonal time scales. Out of 149 blocks, a significant negative rainfall was noticed in 105 blocks. Annual rainfall showed a significant positive trend in a few blocks like Bhopalpattnam, Bijapur, Usur, and Konta. A similar pattern of trend was noticed in the monsoon season. The results of the study demand the urgent need to formulate policies and strategies for water resource management and planning. The blocks which showed the positive rainfall trends can be identified to intensify the cultivation of more water-requiring crops based on the suitability for that region. The findings of this study can be used as valuable information for crop planning, policy-making and preparation of contingency plans. HIGHLIGHTS Significant shift change point identified as 1961, signifying a shift in rainfall patterns.; The monsoon season demonstrated the highest positive trends, contrasting with negative trends in winter during 1901–1961.; Positive trends in the monsoon season persisted, while negative trends continued in the winter during 1962–2020.; The Theil–Sen slope method indicated an overall decline in annual rainfall for most blocks.; The present study highlights the comprehensive micro-level study of the 149 blocks of Chhattisgarh State, and it could be helpful for agro-advisory and policy-making for the state.;