District Wise Comparative Analysis of Rainfall Trends in Konkan-Goa and Marathwada Meteorological Subdivision of India

Abstract

District-wise monsoon (June - September) rainfall trends over Konkan-Goa and Marathwada meteorological subdivisions of India were analyzed in this study using rainfall data for the period 1951-2018. Mean monsoon rainfall is the highest over Konkan-Goa and the lowest over the Marathwada subdivision in the state of Maharashtra, India. Linear regression, Mann-Kendall test, and Sequential Mann-Kendall were used to identify trends in rainfall. Higher variability in the rainfall trends was noticed over the districts of Marathwada (-25% to +25%). The total number of below and above normal rainfall years (20 to 25) were comparatively equal for both the subdivisions; however, the number of deficient and excess rainfall years was more for the districts of Marathwada. Most of the districts in Marathwada showed declining trends in the summer monsoon rainfall. Significant decreasing trends were noticed in June month over Latur (-11 mm/decade) and Osmanabad (-7mm/decade) districts of Marathwada. The decadal rate of change in the overall monsoon rainfall for the Konkan-Goa subdivision varies between -15mm (Mumbai City) to -59mm (Raigad) and +2mm (Beed) to -30mm (Nanded) over the districts of Marathwada. The study has been carried out to understand the behavior of rainfall patterns post 1980, but the results were similar to the overall 68 years’ rainfall trends. In general, insignificant mixed seasonal trends and insignificant negative trends were observed over most of the districts of both the subdivisions, which decline the consideration of monsoon vagaries and droughts due to rainfall change as a manifestation of climate change.