渤海湾大风的特征及其预报

利用1988—2011年渤海湾两个站的大风资料,对渤海湾多年大于17m/s强风特点进行分析,发现冬季以西北风为主,春、夏、秋季以东北风为主,偶尔会出现偏南风。渤海湾海面大于10级的强风主要出现在10月、11月和12月。强风年分布特征呈两峰两谷型,最多月份是11月,最少月份是8月。根据天气学原理和因子统计筛选,发现强风的极大风速与当日最大风速有较好的相关性;对不同下垫面(海面、陆面)分别建立了极大风速与当日最大风速的预报方程。预报方程通过了α=0.01的显著性检验。方程回代拟合率达到75%~94%。将WRF数值预报计算出当日的最大风速值进行订正、代入预报方程、快速计算出强阵风,为灾害性大风预报提供了客观、有效的预报手段。

Characteristics and Forecasting of Strong Wind Gusts in Bohai Bay

Using the wind data of two stations in the Bohai Bay from 1988 to 2010, the characteristics of over 17 m/s strong wind are analyzed. The analysis concludes that in winter, the prevailing wind direction for strong wind is northwest, and in spring, summer, and autumn, the prevailing wind direction is northeast, occasionally south wind; over the Bohai Sea, strong wind of grade 10 plus mainly appears in October, November, and December; the annual distribution of strong wind exhibits a two-peak and two- valley pattern, most frequently in November and least in August. According to the principles of synoptic meteorology and statistic screening, it is found that the extreme wind speed of strong wind has good correlation with the maximum wind speed of the day. The regression prediction equations of the extreme wind speed and the maximum wind speed of the day on the different underlying surface （sea, land surface） are established. The forecast equations passed the test of a=0.01, with a fitting rate of 75% to 94%. The method is used to revise the WRF numerical forecast wind, substituted into the regression equation to calculate strong wind quickly.