Annual rainfall analysis of historical and projected weather for South Interior Karnataka, India

Abstract

The interannual and intraseasonal variations in the ISMR expand has the significant impact on agriculturalsector.The daily gridded rainfall data for the past 40 years (1981-2020) and the climatic projections for the next 20 years(2021- 2040) were analysed at district level across South Interior Karnataka (SIK). Basic statistics such as maximum,minimum, mean, standard deviation (SD), coefficient of variation (CV), and percentage (%) contribution to yearly rainfallwere computed. Further, the Mann-Kendall test was used to find the trend in rainfall (RF) and rainy day (RD). The resultsindicated that RF and RD have a positive trend in the both historical and projected periods. In the past 40 years, the highestannual means of RF and RD were observed in Kodagu district (2031.95 mm and 121) followed by Mandya district (1115.97 mmand 71), and the lowest means of RF and RD were observed in Chitradurga district (482.37 mm and 36) followed byChikkaballapur district (590.20 mm and 41). For the projected 20 years, the highest annual mean RF is expected in Kodaguand Hassan districts (1693.88 mm) and the lowest in Chitradurga, Chikkaballapur and Tumukur districts (1308.12 mm).High number of RD is expected in Bengaluru Rural, Bengaluru Urban, Chamarajanagar, Kodagu, Hassan, Kolar, Mandya,Mysore, Ramanagar districts (127) and low RD in Chikkamagaluru, Davangere and Shivamogga districts (118)