Hydrologic Validation and Flood Analysis

Hydrologic validation centers on examining the utility of satellite rainfall products for applications that concern terrestrial waters. In this chapter the authors focus on streamflow and flood forecasting. As basin response to rainfall is a complex interaction of runoff generation and water transport in the drainage network, satellite rainfall products should be evaluated in that context. This basin-centric view of the validation problem provides new performance metrics that can guide satellite product developers. The authors outline a spatio-temporal framework for studies of satellite-rainfall products. The framework involves a ground-based rainfall reference product available at the basin scale as well as a hydrologic model that can faithfully mimic the basin response to rainfall. As rainfall generated runoff propagates through river network so do the product uncertainties. The authors discuss a statistical analysis of the dependency scale of the river “transported” discrepancies. The results indicate that errors propagate through much longer distances than what a traditional geostatistical analysis would reveal.