Resource to risk: inter-decadal and sub-seasonal rainfall modulation over Saurashtra region in Western India

Abstract

Climate change, recognized as the long-term change in atmospheric conditions is one of the most evident feature of 21st century. Limited studies on Saurashtra's rainfall variability underscore the need to explore temporal and spatial patterns, vital for sustainable water resource management and agricultural planning in the region. This study examines seasonal and sub-seasonal rainfall trends (1981–2020) using high-resolution IMD data, applying Z-score, Mann-Kendall test, Sen's slope estimator, and Rainfall Anomaly Index for analysis. The region has experienced increased variability in rainfall, particularly at the upper extremes. Statistical analysis shows a significant increase in mean rainfall during 2001–2020, with distinct trends compared to earlier decades. Notably, September exhibits the largest upward trend in rainfall at +1.53 mm/year. Seasonal RAI highlights a shift from predominantly negative rainfall anomalies (1981–2000) to positive anomalies in the later period (2001−2020). These findings emphasize studying atmospheric dynamics to understand future rainfall changes.