Local Wind Simulation over Complex Terrain of Chongli Using WRF-LES

Abstract

Utilizing four nested domains of large eddy simulation with Weather Research and Forecasting Model （WRF-LES）， this paper carries out wind simulation test in Chongli area， where is one of the host locations of 2022 Beijing Winter Olympics.Based on surface and lidar data， a clear-sky case with high-pressure system is chosen to evaluate the performance of the model.STRM1 30 m topographic data， glc2015 27 m land use data， and China Meteorological Administration Land Data Assimilation （CLDAS） soil moisture data are introduced to improve the simulated results.In addition， sensitive tests are conducted to evaluate effects of different input data.Results show that： （1） Spatial and temporal changes of simulated winds reasonably agree with observations.The mean absolute error （MAE） of wind direction is 10°~60° and the wind speed is 0.8~2 m·s-1.For wind direction， errors of higher-elevation areas are less than that of lower-elevation areas.The errors are less during the developed period of valley-wind or slope-wind but grow higher when wind shifts.（2） Positive effects are concluded after the update of terrain， land use and soil moisture data.The improvements are most obvious for both wind direction and 2-meter temperature after using CLDAS soil moisture， with MAE values reduced by 4.26° and 0.84 °C， respectively.The wind speed is more sensitive to land use， and the error is reduced by 0.32 m·s-1.（3） The CLDAS soil moisture is obviously lower than that of ERA5.Lower soil moisture can create lower conductivity or lower heat capacity， this state can create stronger surface warming during daytime and cooling at night， and the vertical height of the stronger daytime warming can reach 700~900 m， while the intense nighttime cooling is below 200 m.An apparent wind increase is also noted in lower layers during daytime.These changes are more obvious in valleys and ravines.

Keywords

• wrf-les
• complex terrain
• wind simulation
• cldas soil moisture