A new criterion for identifying breaks in monsoon conditions over the Indian subcontinent

Abstract

The presence or absence of prolonged breaks over the Indian subcontinent during the mid monsoon months of July and August decides the fate of the monsoon rainfall. Using a new criterion for identifying the breaks, we have catalogued them for the period 1901 to 2002. We refer to a situation as a break, if the all India rainfall is less than 9 mm/day and the condition persists for a minimum of three days and if it occurs in the mid monsoon months of July and August. The majority of the breaks in the months of July and August were of 3–4 days duration (49%). Breaks identified by our method were in general consistent with those identified by the conventional methods. Further, the correlation between the seasonal monsoon rainfall and break (active) days identified by the present criteria is −0.80 (0.38) which is more robust than that of the previous studies.