Wet bias of summer precipitation in the northwestern Tibetan Plateau in ERA5 is linked to overestimated lower-level southerly wind over the plateau

Abstract The Tibetan Plateau (TP), also called the Third Pole, is considered to be “the world water tower”. northwestern TP (NWTP), which has an average elevation higher than 4800 m, arid region where summer precipitation largely overestimated by ERA5 global reanalysis product. We hypothesize that this wet bias mainly caused unrealistic lower-level winds trigger strong convection over region; it can reduced using a high-resolution regional climate model with large domain allows realistically representing interactions between Westerlies and Asian monsoons. Here, downscaling Weather Research Forecasting (WRF) driven was conducted (8°‒50° N, 65°‒125° E) at 9 km for period 1979‒2019 (WRF9km). Precipitation values from WRF9km were evaluated against satellite observations; compared ERA5, captured climatological NWTP much-reduced bias. overestimation excessive convective precipitation, likely linked vertical motions induced southerly wind.