江苏沿海近地层风阵性及台风对其影响

为了研究风阵性特征，尤其是在受台风影响时湍流特征对安全开发利用风能资源的影响，利用江苏沿海5座测风塔2009年6月—2012年11月的梯度风观测数据，分析了近地层风阵性基本特征，并筛选了7个对江苏产生较大影响的台风，包括罕见的正面登陆台风达维（1210），分析台风影响下风阵性特征。研究发现:江苏沿海地区低层的风脉动性比高层强，10 m高度的年平均阵风系数和湍流强度分别为1.50和0.20；海陆分布明显影响风阵性，离岸风的湍流强度明显大于向岸风；当风速等级小于6级时，风阵性随风速增大而一致性减小，之后则稳定少变；在台风中心附近，受风速、风向快速多变的影响，湍流强度和阵风系数均远大于台风外围和没有台风影响的情况，湍流强度和阵风系数在30~50 m高度之间增加，在6~7级风时出现风阵性的局部峰值区。

The Wind Turbulence of the Near-surface Layer of Jiangsu Coastal Area and Its Response to Typhoon

In order to study the influence of wind turbulence characteristics on the rational and safe development and utilization of wind energy resources, long-term wind gradient observations are carried out in Jiangsu with five wind towers along the beach. Based on the wind speed and wind direction observations for 42 consecutive months from June 2009 to November 2012, temporal and spatial variation characteristics of the surface layer wind gust factor and turbulence intensity are analyzed. Variation characteristics of gust factor and turbulence intensity with wind speed, the influence of land and sea distribution on gust factor and turbulence intensity are then discussed. Seven typhoons that have great impacts on Jiangsu are selected, including the rare typhoon Damrey in 2012 that landed in Jiangsu, and the typhoon''s influence on the wind is discussed. Results show that the gust factor and turbulence intensity are strong at the height of 10 meters, in the coastal areas of Jiangsu. The annual average gust factor of 10 m and 70 m heights in the coastal areas of Jiangsu are 1.50 and 1.24; the turbulence intensities are 0.20 and 0.11, respectively. The frequency distribution of gust factor and turbulence intensity is unimodal. At lower observation heights, the frequency distribution is wider, the peak is lower, and the peak is biased toward the high value area. The influence of sea and land distribution is obvious. The turbulence intensity of offshore wind is significantly greater than that of onshore wind. The wind speed has a significant impact on gust factor and turbulence intensity, which decrease with the increase of wind speed. When a wind greater than strong breeze happens, the gust factor and turbulence intensity are basically stable and less variable. Near the typhoon center, the wind speed has a bimodal change of increasing-subtracting-increasing, and the wind direction changes rapidly in a short time. The turbulence intensity at 10 m and 70 m heights are 0.25 and 0.14, the gust factor at 10 m and 70 m heights are 1.65 and 1.33, much larger than the value around typhoon and without typhoon. During the passage of the typhoon center, the turbulence intensity and gust factor do not decrease with height and they increase between 30 m and 50 m. When the wind speed increases, the turbulence intensity and gust factor decrease overall, but local peaks may occur when the wind is strong breeze to moderate gale while the typhoon center passes, threatening the safety of the turbine.