Estimating rainfall variability over five districts of northern hill zone of Chhattisgarh state

Abstract

An attempt has been made to study the variability for long term (40 year) rainfall data of five district of northern hill zone of Chhattisgarh state viz. Balrampur, Jashpur, Korea, Surajpur and Surguja. Maximum rainfall and highest rainy days was found at Jashpur (1396.5 mm) followed by Surguja (1360.4 mm). The coefficient of variation of rainfall shows bellow 50 % in all the five districts. The coefficient of variation has been found highest 28.06 % in Surajpur district with least amount of rainfall while it was least (18.20 %) in Jashpur district and it was almost similar in Balrampur 26.89 % Korea 27.02 and Surguja 26.12% in general the annual CV varried from 18-29 %. In case of decadal rainfall variability Jashpur shows maximum rainfall during 1987-96 with lowest (14.83 %) of CV while it was highet 19.9 % during 1997-2006. CV was highest during the decades 2004-2013 (34.7%) and lowest 23.9 during 1994-2003 in Korea but in Surajpur district CV values for annual rainfall was around 30% for all decades except during 1983-1992 which had a of 11%. In Surguja the decade 2001-2010 was drier year over other decades. Whereas the CV was highest (32.8 %) while lowest CV (24.0%) was found during decade of 1991-2000.