Assessment of the Two Successive GPM-Based V3 and V4 GSMaP Precipitation Products at Multiple Temporal and Spatial Scales Over China

Since the beginning of the global precipitation measurement (GPM) era, the global satellite mapping of precipitation (GSMaP) products underwent a major upgrade on January 2017, when the newest Version 4 (V4) GSMaP products were formally released. In this study, for the first time ever, the error characteristics of the successive Version 3 (V3) and V4 GSMaP products were evaluated at multiple temporal and spatial scales by comparing them to the China daily Precipitation Analysis Products from March 2014 to February 2017. The GSMaP products include the V3 and V4 standard products (MVK_V3 and MVK_V4), the gauge-adjusted standard products (GAU_V3 and GAU_V4), and the V3 near-real-time product (NRT_V3). Both versions of the gauge-adjusted datasets exhibit improvements over their corresponding unadjusted counterparts. With regard to the three-year daily mean precipitation, both gauge-adjusted products have similar spatial precipitation patterns, and the GAU_V4 provides higher precipitation estimates than the GAU_V3 over China. The MVK_V4 generally outperforms the MVK_V3 over the high-altitude Qinghai-Tibetan plateau, the deserts, and the moist southern regions. Elsewhere, the MVK_V4 has a lower performance than the MVK_V3. Based on the seasonal statistics, the V4 GSMaP products are superior to the V3 GSMaP products over China in the winter and the MVK_V4 provides higher precipitation estimates than the MVK_V3 in most areas of China (except for the Qinghai-Tibetan plateau and the deserts) in spring, summer, and autumn. The daily statistics show that the MVK_V4 significantly corrects for the precipitation bias of the MVK_V3 in the western, arid, and high-altitude regions.