Evaluation of CMIP6 HighResMIP models in Simulating Precipitation over Tibetan Plateau

High Resolution Model Intercomparison Project (HighResMIP) from the Coupled Model Intercomparison Project 6 (CMIP6), for the first time, provides global high-resolution (25—50 km) multi-model ensemble simulations. Based on simulations of eight CMIP6 HighResMIP models, the performance of the state of the art global high-resolution models in simulating hourly precipitation and extreme precipitation in summer over the Tibetan Plateau is evaluated. The results show that CMIP6 high-resolution models overestimate (underestimate) the precipitation amount and frequency (intensity). The positive bias of precipitation amount is mostly contributed by the overestimated frequency, especially the frequency of weak precipitation (< 2 mm·h^-1). The simulation deviations are closely related to terrain elevation, and the areas with large bias are mainly located in the steep terrain on the south and east slopes of the plateau. The models fail to accurately reproduce the relationship between precipitation amount and elevation, with overestimation (underestimation) of the amount in high(low)-altitude areas. The models underestimate the rate of precipitation intensity decreasing with increasing elevation. In terms of diurnal variation, the models can simulate the late-afternoon and midnight peaks of precipitation over the Tibetan Plateau, but obviously underestimates the diurnal amplitude of precipitation. In terms of hourly extreme precipitation, the models underestimate the 95th percentile threshold of the area-average precipitation intensity in the plateau, which was only 57% of the observed value.