Refined Assessment of Wind Environment over Winter Olympic Competition Zone Based on Large Eddy Simulation

Abstract

The near-surface wind field over complex terrain is highly non-uniform due to the influence of topographical fluctuations. Therefore, it is extremely difficult to carry out high-density observational experiments and refined assessment of wind environment in these areas. In this case, high-resolution wind field data from numerical simulations is essential for the evaluation and analysis of near-surface wind environment. A refined wind environment assessment is carried out for Xiaohaituo alpine skiing field, Yanqing competition zone of Beijing Winter Olympic Games. Firstly, the weather patterns over the alpine skiing field during the winter competition periods from 2009 to 2021 (every February and March) are divided into 5 main types according to the Lamb-Jenkinson (L-J) atmospheric circulation classification scheme, and further classified into 93 secondary circulation types according to the wind directions and speed at 700 hPa. Secondly, the coupled model system of mesoscale meteorology and large eddy simulation (RMAPS-LES) developed by Beijing Institute of Urban Meteorology is used to simulate the wind field at a horizontal resolution of 37 m for typical cases under 93 weather patterns. The comparison between the simulation results and observations at 11 automatic weather stations shows that the model simulation performs reasonably well. The results show that the average deviation of 2 m temperature is less than 2℃, which perfectly meets the accuracy requirements of weather forecast service demand. Although 10 m wind speed is slightly overestimated for the whole typical cases of different weather patterns, the average deviation is within 3 m·s-1, and the average deviation of 10 m wind direction simulation is 10.43°-12.36°, which shows a good prediction skill. Finally, based on the wind field simulation results of different weather patterns, a ten-year winter wind environment assessment is carried out to provide detailed spatial distribution characteristics of the wind field, risk ranges, locations of gale, and the risk probability of exceeding the wind speed thresholds of the sport events, so as to provide technical supports for the organization, time arrangement, track design and wind hazard protection of 2022 Beijing Winter Olympic Games. The method provides an effective way for wind energy assessment and forecast over complex terrain, as well as meteorological services for wind-sensitive activities, such as outdoor mega-events over complex terrain, small-scale environmental design for large-scale architectural complex over mountain terrain, mountain fire disaster prevention and mitigation, mountain pollution forecasting and nuclear proliferation assessment.

Keywords

• wind environment assessment
• large eddy simulation
• complex terrain
• refined numerical simulation