Effect of lake surface temperature on the summer precipitation over the Tibetan Plateau

Abstract There are numerous lakes on the Tibetan Plateau (TP), but the role of lake temperature in precipitation over the TP remains unclear. Here the W eather Research and Forecasting (WRF) model was used to detect the impact of lakes on summer rainfall. Three test cases w ere used to evaluate the effect of lakes surface temperature (LSTs) on precipitation variability. The three cases used different methods to determine initial LSTs, including using sea surface temperature data (SST), the W RF inland water module (avg_tsfc), and a lake model. Results show that when precipitation was stimulated over the TP, LSTs cannot be initialized using SST, which led to large discrepancies of precipitation. Compared with the simulations, the simulated precipitation were improved obviously with LSTs using avg_tsfc, indicating that LSTs have an considerable influence on determining precipitation over the TP. Due to a lack of observational data, the lake scheme does not improve on rainfall simulation, but does effectively simulate precipitation pattern over lakes, such as rainfall over the lakes was dominated by convection during the nighttime. Though the simulated precipitation using SST to initialize LSTs caused large discrepancies, it suggested that precipitation increase especially convective precipitation with increase in LSTs, which confirmed that the moisture from lakes cannot be neglected over the TP. Generally, it was necessary to monitor the LSTs for accurate weather and climate prediction over the TP.

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