Comprehensive evaluation of satellite-based precipitation products at hourly scale in Beijing

With the increase of short-duration rainstorms, accurate precipitation data with higher temporal resolution, such as hours or even minutes, has been required for urban hydrological modeling and forecasting. As a potential data source, hourly or half-hour satellite-based precipitation products (SPPs) perform differently in different metropolitan regions, so evaluation is necessary before their application. Based on the observations of 20 meteorological stations from 2015 to 2018 over a typical metropolitan region, Beijing, a comprehensive evaluation of four widely used SPPs at hourly scale was conducted. Results showed that IMERG and GSMaP had the best performance, followed by CMORPH, while PERSIANN performed worst at hourly scale; it was suggested to use data series composed of wet hours for evaluation at hourly scale with more consistent spatial distribution characteristics and reliable results; IMERG, GSMaP and CMORPH performed better during 9:00-12:00 for accuracy and 5:00-9:00 and 20:00-21:00 for detection capability while PERSIANN didn't show obvious diurnal variation. In addition, the short-duration extreme precipitation in Beijing was defined as an event with an hourly precipitation >20 mm. Overall, hourly or half-hour SPPs still need a lot of progress and our study would provide some significant references for developers and potential users.