WRF numerical simulation of summer precipitation and its application over the mountainous southern Tibetan Plateau based on different cumulus parameterization schemes

Abstract

The extreme scarcity of meteorological observation data caused by harsh natural environments greatly limits our understanding of precipitation and related atmospheric processes over the mountainous regions of the southern Tibetan Plateau and its surrounding areas (hereafter mountainous southern TP). Precipitation simulation has been challenging in this region due to the complex topography and large elevation differences. Considering the high sensitivity of precipitation to the choice of cumulus parameterization scheme (CPS) over the TP, this study systematically evaluated the precipitation simulation performance of 11 CPSs in July 2018 using the WRF model. The characteristics of atmospheric circulation and gradient variation of precipitation were also revealed based on the optimal CPS over this region. The results indicated that the scale-aware schemes (KIAPS SAS [KSAS] and multi-scale Kain–Fritsch [MSKF]) demonstrated excellent potential for precipitation simulations. Due to the reasonable expression of atmospheric stability and the resulting accurate simulation of the timing and amount of regional heavy precipitation events, the KSAS scheme was superior to the MSKF scheme. The output of the KSAS-configured experiment revealed two main water vapor transport channels for the mountainous southern TP in summer, namely the southern monsoonal channel and the western westerly channel. Based on the precipitation profiles along the typical paths of these two channels (longitudinal path of 95.5°E and latitudinal path of 29.5°N), two precipitation belts and one precipitation belt existed on the southern and western slopes of the TP, respectively.