中文摘要：

采用高分辨率卫星资料研究了我国近海6级以上大风的分布特征,并对台湾岛地形对四季的大风的影响进行了数值模拟研究。资料分析表明,冬季大风分布与冬季平均风速分布相似,高频区出现在台湾海峡、巴士海峡和越南东南沿海,黑潮锋暖侧的风频明显大于其冷侧的风频。春季大风频率显著下降,最大值依然出现在台湾海峡,巴士海峡、台湾岛东南角和黑潮锋暖侧也是春季近海风频较大的区域。夏季是近海大风出现最少的季节,风频最大值在10°N附近的南海西部,由西南向东北减少,台湾岛周围的风频呈现东南、西北大,西南、东北小的近似轴对称分布,大风方向为绕岛逆时针环流。秋季大风风频迅速增大,基本呈现出冬季的形态。数值模拟表明,不同季节地形对大风的影响程度不同,冬季台湾岛地形对其周围海区大风的形成有重要贡献,去除地形后,台湾海峡和岛屿东南角的大风消失,风速变为由南向北递减。夏季去除地形后,岛屿周围的大风几乎没有改变,本文将从大风产生的原因对其进行解释。

英文摘要：

This work investigates the distribution of high winds at scale 6 or above in off shore zones of China using high-resolution satellite measurements.A numerical experiment is carried out in order to find out the effects of Taiwan island on the formation of strong winds.The analysis indicates that the distribution of high winds occurrence is similar to that of the average wind velocity in winter.High winds tend to be anchored in special topographical regions such as the Taiwan Strait,the Bashi Channel and the southeast coast of Vietnam.High winds occur much more frequently over the warmer than the colder flank of Kuroshio front as it meanders from Taiwan to Japan.The frequency of high winds decreases drastically in spring.The Taiwan Strait maintains largest of high wind occurrence.Besides,high winds remain frequent in the Bashi Channel,the southeast tip of Taiwan island and the warmer flank of Kuroshio front.In summer,high winds generally occur infrequently except over a broad region off the southeast coast of Vietnam near 10 °N and the frequency there decreases from southwest to northeast.High winds around Taiwan island present near axisymmetric distribution with larger frequency along southeast-northwest direction and smaller frequency along southwest-northeast direction.The dominant direction of high winds exhibits a counterclockwise circulation surrounding the island.The frequency of high winds increases rapidly in autumn and almost represents the distribution that appears in winter.The simulation results suggest that the effects of Taiwan island orography on high winds vary with seasons.In winter,orography is the major cause of high winds in the surrounding oceanic zones.High winds both in the Taiwan Strait and in the southeast corner of the island disappeared and the frequency decreased gradually from south to north when the terrain was removed.However,in summer,high wind frequencies which derived from two simulations with and without terrain are almost identical.We attribute this phenomenon to the factors wh