Statistical and probability analysis of rainfall for crop planning in a canal command

Abstract

In the present study, statistical and probability analysis of 40 years daily rainfall data for the period 1971-2010 were carried out on weekly, monthly and annual basis. Rainfall pattern in the area is also analyzed using thiessen polygon and Histogram technique. Probability analysis was done using two and three parameters probability distribution functions. The best distribution representing the command was identified using Chi-squared ( 2) test at different probability level. Amongst the nine distributions fitted in the Tawa canal command, Log-normal distribution and Weibull distribution (2) are found as the best fit distribution for annual and monthly rainfall data respectively. When the distributions depicting standard monsoon and non-monsoon weeks in the region are studied, it has been found that Beta and Weibull represents best in comparison to other distributions. Finally, the best fit distribution is employed for computing the minimum assured amount of rainfall at different probability levels for the command area.