Association of Agrometeorologists

A modified approach for determination of onset and withdrawal of monsoon

A.K.KOTHARI, VIRENDRA KUMAR, P.M.JAIN, and R.C.PUROHIT

Onset of monsoon is an important rainfall characteristic for drought management and crop planning. Morris and Zandstra method for onset was compared with observed values for a period of 20 years, which revealed a mismatch in the Bhilwara region in 40 per cent of years. The criteria for rainfall accumulation for both onset and withdrawal was modified in such a way that the determined and observed onset of monsoon showed a significant match. For early and late onset of monsoon and intermittent low /nil rainfall weeks. Withdrawals were adjusted and length of growing period for Bhilwara region was determined.

Onset of monsoon, withdrawal of monsoon, length of rainy season, crop planning