Satellite Rainfall Error Analysis with the Use of High-Resolution X-Band Dual-Polarization Radar Observations Over the Italian Alps

Abstract

Flash floods are associated with heavy precipitation events often induced by rough topography. The accuracy and reliability of hydrological modeling studies depend on the quality and availability of precipitation estimates. Current operational rainfall monitoring systems based on national weather radar or rain gauges networks cannot provide an accurate estimation of the high variability of precipitation in complex terrain. Satellite-based precipitation measurements are quasi-global and high resolution, and can potentially be used for filling this observational gap. During the last decade, an impressive progress has been made in the application of satellite rain retrievals products by tuning the space and time resolution of satellite products to satisfy the needs of operational hydrology. However, these products have uncertainties, like the requirement for bias adjustment, which necessitate the use of correction procedures against more accurate ground-based rainfall measurements. This study makes a preliminary evaluation of satellite rainfall estimates from satellite passive microwave measurements and the more recently deployed GPM dual-polarization precipitation radar against high spatial and temporal resolution rainfall estimates obtained with a dual-polarization X-band mobile radar during a field experiment which took place in the time period August and September 2014 in North-East Italian Alps.