Lake-atmospheric Interaction and its Impact on the Local Precipitation over Nam co region

Nam Co Lake is the third largest salt lake in China. Nam Co Lake is a typical inland salt lake and a typical representative area of the complex topography of the Tibetan Plateau. In this study, the effects of Nam Co Lake on the short-term climate in the lake area are analyzed using the Weather Research and Forecasting (WRF) model in conjunction with field observation data for the Nam Co Lake area through a control experiment on the Nam Co Lake area and a sensitivity experiment on the same area without the presence of Nam Co Lake. Moreover, a backward water vapor transfer model is also employed to investigate the contribution of water vapor evaporation (transpiration) from this typical plateau lake and various types of surfaces to local precipitation. The following conclusions are derived: (1) After the removal of the lake, the sensible heat in the original lake area increases, whereas the latent heat decreases. The sum of the sensible and latent heat in the lake area simulated with and without the presence of the lake is 187.6 and 116.7 W·m^-2, respectively. (2)After the removal of the lake, precipitation in the central Nam Co Lake area increases significantly, generally by more than 20–30 mm. The presence of Nam Co Lake effectively reduces the height of the ABL over the lake during the day. (3) Approximately 76.93% of the total precipitation in the Nam Co Lake area is contributed by external water vapor sources. Evapotranspiration from grassland surfaces is the secondary water vapor source for precipitation in the study area and 18.34% of the total precipitation is contributed by this source. Approximately 2.46% of the total precipitation in the lake area is contributed by evaporation from Nam Co Lake.