Weekly Rainfall Analysis using Markov-Chain Model for VC Farm Mandya District, Karnataka

Abstract

The present study has been carried out at Zonal Agricultural Research Station which is located at Mandya district in Karnataka state under agro-climatic zone 6 (Southern dry zone) having longitude of 76° 49.8’ E and latitude of 12°34.3’ N with an altitude of 697 meters above the mean sea level to find the probabilities of occurrence of wet week (Pw), dry week (Pd), wet week preceded by wet week (Pww), dry week preceded by dry week (Pdd), two and three consecutive wet and dry weeks (P2w, P2d, P3w and P3d) at a threshold rainfall limit of 20 mm week-1. Weekly rainfall data of 26 years (1991-2018) obtained from Agromet observatory, ZARS, Mandya, University of Agricultural Sciences, Bengaluru was studied for spell distribution using Markov Chain Model. For this purpose a week period was considered as the optimum length of time. The results revealed that, the probability of occurrence of wet weeks during the pre monsoon season starts effectively from 15th May to 15th June in the study area. The chance of occurrence of two or three consecutive wet weeks was high during rainy season, whereas, rest of the period during the year was more prone to have two or three consecutive dry weeks.