Application of Noah-MP in Numerical Forecast in North China: case study

Noah land surface model is applied in the Rapid-refresh Multi-scale Analysis and Prediction System-Short Term (RMAPS-ST) that is used for the numerical forecast for North China. Noah-MP is a land surface model with multi-physical processes based on Noah. It is worthwhile to investigate how well Noah-MP can be applied in the RMAPS-ST. Therefore, we selected individual case of sunny, cloudy, snowy, and rainy days to conduct numerical experiments and mechanism analysis in North China. The results are shown below. (1) Compared with Noah, Noah-MP has some advantages in the RMAPS-ST. The improvement of wind speed forecast in North China is more significantly than that of air temperature and specific humidity by applying Noah-MP land surface model. (2) The application of Noah-MP has more obvious improvement in the forecast performance of air temperature on sunny days, specific humidity during snowfall, and wind speed on cloudy days. The forecast accuracy of wind speed on cloudy days is increased by about 50.43%. (3) The application of Noah-MP has improved air temperature forecast mainly in the middle and south of Shanxi Province, the middle and south of Hebei Province, and Shandong Province. The improvement of specific humidity forecast is mainly concentrated in the middle and north of Shanxi Province and the north of Hebei Province. The improvement of wind speed forecast is mainly concentrated in the vicinity of mountains. (4) For Beijing, Noah-MP with Chen97 option for surface layer drag coefficient (SFC) and SIMGM option for runoff and groundwater (RUN) has a better effect on the simulation of surface energy fluxes and air temperature, while the options for radiation transfer (RAD), runoff and groundwater (RUN) do not have a significant effect on the forecast results of specific humidity and wind speed.