Abstract

Rainfall records of 52 years (1944-95) of Parbhani station located in the assured rainfall zone of Maharashtra state were critically examined for establishing the long term averages of monthly rainfall and its temporal variability by deploying appropriate statistical techniques. The deviations in normal time(s) of onset and withdrawal of monsoon, depths of monthly rainfall and their distribution were defined as aberrations. The results revealed that the average monsoon rainfall (monthly total) of 849.96 mm was distributed in the proportion of 18.13, 26.94, 25.28, 21.61 and 7.93 per cent during June to October, respectively. The variabilities in normal rainfall during crucial months of August (67.69 %) and October (119.48 %) were relatively higher than remaining monsoon months. The probabilities of normal onset (25th MW) and withdrawal (39th MW) were 44.23 and 50 per cent, respectively. The corresponding probabilities of aberrations were 55.77 and 50 per cent. The per cent probabilities of aberrations in seasonal (June to October) amount of rainfall was 56.54 per cent, with higher proportion of below normal (39.23) than its above normal (27.31) rainfall during June to October. The per cent probabilities of recupation of preceeding deficiency in succeeding months decreased with the advancement of time of occurrence of deficiency.

Keywords: Weather parameters, Average, Variability, Onset, Withdrawal, Spells