Simulation on the Afternoon Convective Precipitation Triggered by Soil Moisture over the Tibetan Plateau

The Tibetan Plateau has an average elevation over 4000 m and it is known as the world's "third pole". Under the background of global warming, the soil moisture over the Tibetan Plateau has changed. Since the soil moisture performs as a key factor in the land surface process and the feedback between the soil moisture and the precipitation is an important part in the land-atmosphere interaction, this research focuses on investigating the influences of soil moisture change on triggering and inhibiting afternoon convective precipitation over the Tibetan Plateau by designing sensitive experiments using WRF model and the CTP-HI_low framework. The results show that the WRF model can reproduce the spatial distribution of the precipitation. To some extent, there are improvements of the precipitation on the west part of the Tibetan Plateau when soil moisture decreases in the numerical simulation. In general, the status of atmosphere dominates the occurrence of convective precipitation process over the Tibetan Plateau, which accounts for about 60% to 90%. But, when the soil moisture dominates, there are more positive cases than negative cases. The amount of convective precipitation triggered by negative process accounts for greater proportion in the northwest arid part of the Tibetan Plateau with the center value up to 80% or more. In addition, by comparing the values of CTP and HI_low, they vary in different years.