基于CCMP风场的中国近海18个海区海面大风季节变化特征分析

Seasonal Variation Analysis of Sea Surface Winds in China Sea Areas with CCMP Wind Field Data

利用1988—2010年CCMP(Cross Calibrated Multi-Platform)高时空分辨率10m风场分析了我国近海海区的大风(6级以上)日数和大风风速的空间分布特征,并且按照中央气象台对近海海区的划分,分析了近海18个海区大风的季节变化特征。我国近海大风日数高值中心及大风风速高值中心都集中于巴士海峡、台湾海峡和南海东北部海域,在巴士海峡和南海东北部海域交界处最高可达140天以上,平均大风风速达到13m/s以上。从季节变化来看,大风日数和大风风速充分体现了东亚季风冬强夏弱的特点。冬半年,大风日数及风速高值中心一直位于东海东北部、台湾海峡、巴士海峡、南海东北部以及南海西南部海域,12月是一年之中大风日数和强度的峰值时期。从4月开始,南海西南部的高值中心消失,而以北海域的高值区的分布基本不变,这种情况一直持续到9月。近海18个海区的季节变化呈现出不同的区域差别,南海中部和南部的4个海域大风日数呈双峰型变化,冬季的12月至次年1月出现最高值,夏季西南季风时期的7—8月出现次高值。除琼州海峡外,包括南海北部海域的其余13个海区高值均在冬季12月至次年1月,低值出现在夏季6—7月。

The spatial patterns of sea surface strong wind （beyond Beaufort wind scale 6） in the China Sea are analyzed through adopting the high resolution Cross Calibrated Multi-Platform （CCMP） wind data. According to the definitions of the China costal sea-areas by the National Meteorological Center （NMC）, the seasonal variations of the strong wind days in these 18 sea areas are also examined. The analysis results show that the highest values of strong wind days and speed are centering around the Bashi Channel, Taiwan Strait and the Northeast part of South China Sea （SCS）. The seasonal variations in coastal China seas can obviously reflect that the East Asia monsoon is strong in winter and weak in summer. In winter, the centers of strong wind days and speed always locate in the northeast part of ECS, Bashi Channel, Taiwan Strait, and the northeast part of SCS, and the maximum days and strongest speed appear in December; while in summer, these centers disappear. The center locating in the southwest part of SCS disappears from April. However, the seasonal changes of the strong wind days in these eighteen sea areas are different. Those in the middle and south parts of SCS have two peaks： one occurring from December to January, and the other from July to August. While in other thirteen sea-areas, the high value of the strong wind days appears from December to January and the low one from June to July.