Atmospheric drivers of major flood producing storms in India

There is a general increase in the frequency and severity of flood events in India, becoming new normal and, likely to increase further in a warmer climate. Each flood event has a unique rainfall signature in terms of moisture sources, pathway, intensity, duration, and spatial extent. To understand this, we analyze the rainfall signatures that caused major floods in the Narmada basin, using it as a test-bed. We find that along with atmospheric characteristics, catchment and other river-system drivers also impact the flood characteristics. However, we focus only on atmospheric drivers in this study. We use the Variable Infiltration Capacity (VIC) model to simulate streamflow at different locations in the basin and identify major flood events. For this, backtracking algorithms will be used to identify the moisture sources and tracks that deliver it to cause the floods. Tropical Rainfall Measurement Mission Precipitation Radar (TRMM PR) data will be used to identify the location of the centre of storms, and the spatial extent of the storm. The Variable Infiltration Capacity (VIC) model will be employed to simulate the major flood events, incorporating the atmospheric information. We will also investigate the catchment and river-system controls that modulate the precipitation signature in producing the floods. Identifying the linkage between the atmospheric and land characteristics and, floods can help in establishing effective flood early warning systems to enhance resilience.