Probability analysis of rainfall distribution in Sambalpur district of Odisha

Abstract

The distribution of rainfall has great variation over time. This results in drought, abnormal and normal rainfall in different years. The statistical study of rainfall probability is of utmost importance due to the random nature of rainfall pattern. This study can be of much utility for crop planning. The probability distribution of drought, normal and abnormal rainfall at Sambalpur district in western Odisha is studied monthly and seasonally from rainfall data for period of 24 years (1993-94 to 2016-17). The month having monthly rainfall less than half of mean monthly rainfall is regarded as drought month, more than twice the mean monthly rainfall is regarded as abnormal month and in between half and twice of the mean monthly rainfall is regarded as normal month. The probability of normal rainfall remains high during kharif season (June – September) with very low probability occurrences of drought months. The probability of drought months remains high in rabi season, whereas, in summer season the probability of abnormal months remain high. The C.V. of rainfall is less in months having more rainfall and increases in dry months. December, the driest month is having highest C.V. and August, the wettest month is having second lowest C.V. Thus the wet months are consistent in rainfall and the drier months are having high uncertainty of rainfall.