Decoding Rainfall Diversity: A Long-Term GIS Assessment of the Chikkamagaluru Region
DOI:
https://doi.org/10.12974/2311-8741.2025.13.07Keywords:
Rainfall variability, Kriging, Chikkamagaluru, Trend analysis, Mann–Kendall, Sen’s slope, Western ghats, GISAbstract
This study analyses long-term rainfall variability across Chikkamagaluru, Mudigere and Belur taluks using a 47-year continuous dataset (1977–2024). Spatial interpolation (Ordinary Kriging, 1 km × 1 km resolution) and temporal trend diagnostics (Mann–Kendall, Sen’s slope) were used to quantify seasonal patterns and windward–leeward gradients. Mean annual rainfall across the region is 1769 mm, with monsoon rainfall contributing 80–86% of yearly totals. Windward stations such as Kottigehara and Hosakere receive 3–4 times more rainfall (up to 4170 mm) than leeward stations such as Kalasapura (~680 mm). Trend analysis indicates weak but notable seasonal trends: monsoon rainfall shows non-significant decreasing tendencies at most leeward stations, while pre-monsoon rainfall shows slight increasing trends (Sen’s slope +1.8 to +3.2 mm/year). Spatial rainfall maps and trends align strongly with Western Ghats orography and established monsoon climatology. These findings enhance hydro-climatic understanding and provide actionable insights for watershed planning, agriculture, and hazard mitigation.
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