Comprehensive evaluation of satellite and reanalysis precipitation products over the eastern Tibetan plateau characterized by a high diversity of topographies

Abstract

Quantitative evaluation of the performance of satellite and reanalysis precipitation datasets is challenging but indispensable for hydroclimate research on poorly gauged regions. This study comprehensively assesses satellite precipitation products (IMERG_E, IMERG_L, IMERG_F, CHIRPS, TRMM_3B42, TRMM_3B42RT) and reanalysis product (ERA-Interim) over the eastern Tibetan Plateau from 2008 to 2019. Each dataset's accuracy features are evaluated based on gauge observations (184 rain gauges) at various temporal scales (i.e., daily, monthly, and annual), elevations and precipitation intensities. Especially, on the topography's influence on precipitation, the spatial consistency is analyzed based on the extended triple collocation (ETC) approach along with the gauge-based gridded precipitation dataset. The results show that: (1) IMERG_F is more consistent with gauge observations and achieves the best overall performance. All products overestimate precipitation amounts, they present lower CCs (CC: 0.13–0.42) with gauge observations at daily scale, whereas show higher (CC:0.68–0.93) and acceptable CCs (CC: 0.49–0.79) at monthly and annual scale, respectively. (2) Seven products have ability to detect precipitation occurrence and extreme precipitation, the probability of detection is higher for tiny and light precipitation events and the false alarm rate is larger for extreme precipitation events. In addition, the ability of precipitation products to reproduce heavy precipitation events, both in terms of the occurrence date or precipitation amount, needs to be improved. (3) The accuracy of precipitation products varies with elevation, which has relatively good performance in high elevations. (4) The ETC analysis suggests that the accuracies are increased abruptly from the eastern edge of the Tibetan Plateau to the Sichuan Basin because of the sudden drop of terrain. ERA-Interim exhibits better performance than others, indicating reanalysis product has excellent potential in complex terrain regions. This study demonstrates new findings on the uncertainties of various precipitation products over topographical complex mountainous.