一种概率方法在沿海海岛台风阵风预报中的应用试验

利用2004—2013年浙江影响台风及9个沿海海岛气象站风力资料,分析了各站阵风系数总体特征,及其与站点纬度、海拔高度和海岸线距离等因子的关系。结果表明,随着平均风速的增大,对应的阵风系数有减少趋势;距离海岸线近的站点和海拔高度小的站点其阵风系数也相对要大些。分析台风参数与阵风系数关系,得出阵风系数与台风7级风圈半径和站点离台风中心距离的比值具有最好相关。利用分位数回归方法建立概率预报模型,试报表明大部分站点阵风的50%和90%概率范围的击中率都符合预期,其波动范围一般在3%以内,模型表现比较稳定,对业务有一定的指导价值。

Application Test of a Probability Method in Forecasting Coastal Gusts of Tropical Cyclones in Zhejiang

Using the data of typhoons influencing Zhejiang from 2004 to 2013 and the corresponding winds of 9 coastal meteorological stations, the characteristics of gust ratio and its relationship with the latitude, altitude, and distance from coast to stations are analyzed. The results show that with the increasing of average wind, the gust ratio has decreasing tendency. The gust ratios of stations with less distance away from coast or less altitude are relatively larger. The relationship between typhoon parameters and gust ratio is analyzed. The ratio of the radius of grade 7 wind circle to the distance of the station from typhoon center is well correlated with gust ratio. Based on the quantile regression, the probability forecast models are developed. The forecast tests show that the hit rates of 50% and 90% are obtained for most stations, and its variation is generally within a range of 3%.