Mean diurnal cycle of monsoon precipitation: Unified model NCUM

Abstract

It is an essential component of the operational weather forecast agencies to capture the diurnal behavior of the rainfall on the spatiotemporal scale by numerical models for its accurate prediction. In this study, the mean diurnal cycle of precipitation is investigated with (i) atmospheric model-based predictions, (ii) space-based estimates, and (iii) ground-based rainfall observations during the active phase of Indian monsoon. Further, high-resolution precipitation data are used to identify the characteristics features of the model forecasts. The variability of mean diurnal variations in rain rate and frequency of rain is analyzed to determine the characteristics feature of precipitation. It is found that precipitation activity over Western Ghats, Bay of Bengal regions, is maximum during late afternoon. The time of peak rain rate is advanced during day time. The active phase of monsoon has the highest amplitude of diurnal variation in precipitation. The variability in the specific humidity is increased during this active period. The numbers of rainy hours are highly varying in nature for the space-based rainfall estimation than the model.