Accuracy of satellite precipitation products in data-scarce Inner Tibetan Plateau comprehensively evaluated using a novel ground observation network

Study region: Inner Tibetan Plateau (ITP) is the largest plateau in the world, with only four national basic stations covering an area of 5.76 x 105 km2.Study focus: Satellite precipitation products (SPPs) have widely been evaluated on a regional scale. However, a comprehensive quantitative evaluation of SPPs using multiple indices has not been reported. Here, 16 SPPs were quantitatively and comprehensively evaluated for precipitation occurrence and time series using an improved rank score (RS) method. The new observation network, which had more than the number of national stations, was applied for evaluating SPPs to increase the reliability of results.New hydrological insights for the region: Integrated Multi-satellite Retrievals for the Global Pre-cipitation Measurement (IMERG)-Early and IMERG-Late runs showed the best overall perfor-mance, with an RS value of 0.91. The optimal SPPs varied according to the evaluation indices but mostly belonged to IMERG-Early, IMERG-Late, Multi-Source Weighted-Ensemble Precipitation (MSWEP), Global Satellite Mapping of Precipitation near-real-time (GSMaP-NRT), and Precipi-tation Estimation from Remotely Sensed Information Using Artificial Neural Networks (PER-SIANN) Dynamic Infrared Rain Rate near-real-time (PDIR-Now). Overall, most SPPs detected precipitation; however, the SPPs poorly measured the precipitation time series but adequately detected precipitation in the range of 10-25 mm in terms of the three indices of precipitation occurrence. The proposed improved RS method can be used to comprehensively evaluate other products and models.