Waiting Time and Clustering of Indian Summer Monsoon Daily Precipitation Extremes

ABSTRACT The characterisation of temporal variability of Indian summer monsoon precipitation events in a warming world is critically important for the densely populated and predominantly agrarian Indian region due to obvious socio‐economic impacts. In this study, the temporal distribution of Indian summer monsoon daily precipitation events is analysed in terms of waiting time between events and serial clustering of events. The fractional Poisson exponent and extremal index are used as the quantifiers for this purpose, respectively. It is demonstrated that the waiting time between extreme precipitation events is power‐law distributed with long‐range dependence. This indicates that there is a finite probability of recurrence of rarer extreme events within a season. The waiting time between extreme precipitation events is becoming shorter in central India, western India and northeast India due to global warming. The extremal index analysis of extreme precipitation events suggests that there is a strong tendency of serial clustering of precipitation extremes over India. Our results also suggest that barring southern peninsular India, there will be an overall increase in the tendency of serial clustering of extreme precipitation events in a warming climate. Our findings of temporal variability of extreme precipitation over India due to climate change may exacerbate the already serious urban flooding problem due to human activity.