Meteorological drought analysis based on rainfall data of coastal odisha

Abstract

A 20-year analysis (1990–2009) of rainfall data of Cuttack district of coastal Odisha indicated an average annual rainfall of 1,649.8mm with a standard deviation of 375.9mm. The standard deviation of rainfall is higher in the monsoon months, whereas the coefficient of variation is higher in the non-monsoon months. The rainfall data was analyzed to study the monthly and yearly drought of the study area. Out of the 20 years, there were three drought years with the year 1996 being the most severe drought year wherein only an annual rainfall of 797mm was received. The dry spell and wet spell analysis by the Markov chain model was done, and it was found that there is a high probability of availability of assured water for irrigation water during the 24th to 38th week. The probability analysis of the monthly rainfall data indicated that the two-parameter log-normal distribution was found to be best fit to the rainfall data of January, February, March, and December; Pearson type III distribution for April and November; log-Pearson type III distribution for May, June, August, and October; Gumbel type 1 extremal distribution for the month of July; and normal distribution for the month of September.