Are Recent Satellite-Based Precipitation Products Useful for Flood Identification at Humid Basins?

Abstract:

The applicability of recent Global Satellite Mapping of Precipitation (GSMaP) products has been evaluated for heavy precipitation identification leading to basin scale flooding in South East Asia. GSMaP_MVK and GSMaP_Gauge series were compared to available ground rain gauge network observation. This study attempts to show feasibility of GSMaP family to enhance temporal and spatial precipitation patterns understanding to be used as input for basin scale hydrological processes simulation. It was used GSMaP for temporal downscaling from daily local rain gauge to sub-daily in order to detect flood timing and magnitude at higher resolution in Huong basin (1500 km²) in central Vietnam. After using as input to a distributed hydrological model it was possible to identify evolution of flood peaks in closer agreement to observed stream flow with GSMap_Gauge than GSMaP_MVK. The spatial pattern of these products was reproduced in Tone River (17000 km²) Japan when compared to high resolution local ground-based radar products. In this basin GSMaP_Gauge showed an inverse relationship between the precipitation intensity bias and elevation. Actually, precipitation was underestimated mountain regions and slightly overestimated at lowlands. So far the results indicate that both GSMaP products still underestimate daily precipitation intensities, but they were able to depict spatial patterns. GSMaP_Gauge showed better precipitation detection ability than GSMaP_MVK at both test basins in terms of statistical indicators such as Pearson’s correlation and probability of detection. In short, latest GSMap products were found useful to identify precipitation pattern in two steep highly vegetated basins and feasibility to simulate river flow. Satellite products can be support flood peak identification when combined with available local observed precipitation. This evaluation can provide feedback for parameterization of satellite products at basin scale which is expected to consider with the most recent product: Global Precipitation Measurement (GPM).