Are the Latest GSMaP Satellite Precipitation Products Feasible for Daily and Hourly Discharge Simulations in the Yellow River Source Region?

Global Satellite Mapping of Precipitation (GSMaP) products, as important satellite-based precipitation products (SPPs) of Global Precipitation Measurement (GPM) mission, have provided hydrologists with critical precipitation data sources for hydrological applications in gauge-sparse or ungauged basins. This study statistically and hydrologically evaluated the latest GPM-era GSMaP SPPs in real-, near-real- and post-real-time versions at daily and hourly temporal scales in the sparsely gauged Yellow River source region (YRSR) in China. It includes the five latest GSMaP SPPs, namely, gauge-adjusted product (GSMaP-Gauge), microwave-infrared reanalyzed product (GSMaP-MVK), near-real-time product (GSMaP-NRT), near-real-time product with gauge-based adjustment (GSMaP-NRT-Gauge), and real-time product (GSMaP-Now). The statistical assessment showed that among all five GSMaP SPPs, GSMaP-Gauge presented the best overall performance in daily and hourly precipitation detections in YRSR, followed by GSMaP-Now. GSMaP-NRT-Gauge was ranked the third, whereas GSMaP-MVK and GSMaP-NRT had relatively inferior performance. Given that GSMaP-Gauge demonstrated the best quality among all evaluated GSMaP SPPs, GSMaP-Gauge displayed the best hydrological feasibility in daily streamflow simulation. Both GSMaP-MVK and GSMaP-NRT presented inferior hydrological capability, with a considerable overestimation of the total streamflow. In contrast, GSMaP-Now and GSMaP-NRT-Gauge displayed basically acceptable hydrological performance in daily discharge simulations. In terms of hourly flood simulations, the performance of GSMaP-Gauge slightly worsened but was comparable to the rain-gauge-based precipitation data set. Following GSMaP-Gauge, GSMaP-Now and GSMaP-NRT-Gauge obtained certain predictability of flood events. In general, GSMaP-MVK and GSMaP-NRT barely had hydrological utility for flood-event simulations.