Analysis of Seasonal and Annual Rainfall variability and Trends for Selected Stations of Tripura, India

Agriculture is the primary livelihood for most of the people in Tripura state falling under northeast, India. The type and pattern of farming in the state are significantly influenced by rainfall distribution, which varies greatly over time and across different locations. Understanding long-term seasonal and annual rainfall variability and trend patterns are essential for effective water resource management, optimizing the use of rainwater for the drinking, domestic and agricultural use. This study used non-parametric tests, notably Mann-Kendall and Sen slope estimator to determine trends in seasonal and annual rainfall data in Tripura state. Monthly meteorological data from 2000 to 2019 was used from fifteen stations across the state. The seasonal and annual rainfall time series were used for analyzing rainfall variability and detection of trend pattern. The findings revealed that the coefficients of variation for the monsoon season ranged from 15.36% to 83.95%. Kamalpur recorded the largest coefficient of variation during the northeast season (78.31%), while Kanchanpur had the lowest (42.38%). No significance trend was observed for in any of the stations during the monsoon season; however, there were indications of significance for other periods. Similarly, no significance trend was observed in any of the stations throughout the winter and summer season, except for Sabroom in summer, which showed a considerable decrease in slope. Notably, Bishalgarh experienced a significant decrease in annual rainfall (Z = -2.64, B = -84.1), while other stations did not show any significant trends. Findings of the study highlighted the need for improved rainwater harvesting, climate-resilient agricultural practices, and enhanced water storage infrastructure to mitigate risks from rainfall variability.