Validation of space-borne radar precipitation retrievals using disdrometer data over Italy

Abstract

In spite of the high relevance of the satellite data for collecting information regarding precipitation at global scale, validating satellite retrievals with measurements collected by sensors at ground is still a challenging task. To date, the Dual-frequency Precipitation Radar (DPR) aboard the Core Satellite of the Global Precipitation Measurement (GPM) mission is the only one able to provide, at global scale, vertical profiles of rainfall rate, radar reflectivity, and Drop Size Distribution (DSD) parameters. In this study, we compare near surface GPM retrievals with almost 6 years of DSD parameters estimated by a laser disdrometer in Rome (Italy) since the launch of GPM mission. The comparison shows limited difference in performances of the different GPM algorithms, also with reference to the dual frequency algorithm with respect to the single frequency one. Furthermore, the agreement between satellite and ground based data depends on the considered precipitation variable as well as on the spatial and temporal scale matching constrains.