关键词: WRF, 大涡模拟, 辐射雾

Abstract:

A wide range of radiation fog shrouded North China at 18:00 on January 21, 2013. Based on mesoscale model of WRF (the Weather Research and Forecasting Model) V3.5.1, the predictability of this case is discussed, through comparison between different horizontal resolution of the boundary layer scheme (BLS) and large eddy simulation (LES) scheme. The results indicate that there exists a certain capability to simulate this fog through the BLS, but also exists a delay of 3 hours; however, through LES, both of the occurrence time and distribution of fog can be well simulated. More accurate results can be obtained by improving the horizontal resolution, which makes the occurrence time and distribution closer to the observation. Further analysis shows that, compared with BLS, LES simulates lower temperature of the surface, more water vapor, higher relative humidity and earlier occurrence of the temperature inversion. As a result, in this example, LES is capable of significantly improving the forecast skill of the mesoscale model for radiation fog in North China.

Key words: WRF, large eddy simulation, radiation fog