Dynamical features of incessant heavy rainfall event of June 2013 over Uttarakhand, India

Abstract

The southward penetration of mid-latitude westerlies and their interaction with monsoon current are harbinger of intense rainfall activity over northern and central India. Such synoptic condition prevailed during June 14–17, 2013, and unleashed relentless rainfall over the state of Uttarakhand. Observational aspects of this event have been explored using surface, satellite and reanalysis data. Precipitation features have been explored using data from Precipitation Radar Onboard TRMM satellite in conjunction with TRMM-TB42, Automatic Weather Station and Automatic Rain Gauge Station data. The ERA interim dataset has been used to explore prevalent synoptic conditions, and Modern-Era Retrospective Analysis for Research and Applications reanalysis fields revealed that prevalent synoptic features led to moisture flux convergence in lower troposphere. Vertically integrated water vapor transport over the India and adjoining oceanic region is evaluated to gain an insight into the dynamical mechanism of rainfall activity over Uttarakhand. Results reveal that interplay between movement of monsoon low along the monsoon trough resulting in strong low-level convergence and constant feeding of moisture from Arabian Sea and Bay of Bengal and strong upper-level divergence owing to southward intrusion of mid-latitude westerly trough resulted in heavy rainfall activity over Uttarakhand.