An algorithm for objective forecasting of gust winds at 100 m horizontal resolution based on a gust coefficient model

The rapid development of economy and culture in Beijing-Tianjin-Hebei region has a higher requirement for instantaneous strong wind forecasts. Correctly estimating and predicting instantaneous strong winds on the ground level in winter, especially accurate high-resolution grid-point forecasting of gusts under complex terrain condition, is of great significance for improving the service for major Winter Olympics events, the safe operation in the capital and surrounding cities, and disaster prevention and mitigation capabilities. This study establishes a relationship between the gust coefficient and wind speed, wind direction and terrain height based on long-term series of observation data in Beijing-Tianjin-Hebei. Combined with objective statistical analysis method, gust observation data fusion technology and grid point deviation correction technology, an objective gust forecast method is developed, which not only retains the model physical parameters and local climate characteristics, but also utilizes the grid point deviation correction technology. The results of batch verification and case analysis during the Winter Olympics show that the average absolute errors in the Zhangjiakou competition area and the Yanqing competition area are below 2.3 m/s and 3.0 m/s, respectively. The forecast score of gust wind speed above level 8 in the Yanqing competition area is above 0.5. It solves the bottleneck problem of large gust prediction errors and meets the on-site service requirements of major Winter Olympic activities.