南海海表风速、波高的变化趋势

Variation Trend of Surface Wind Speed and Wave Height of South China Sea

文章以ERA-40资料为基础,利用EOF方法分析南海海面风速、波高的两个模态空间分布,系统计算1957—2002年南海海表风速、波高的空间分布特征、长期变化趋势和突变现象。分析结果显示,南海海面风、浪场的第一模态具有很好的相似性,第二模态已表现出不同的特征;第一模态的时间系数也表明风场和波高的变化特征具有明显的正相关性,而且波高的响应具有一定的滞后性;南海风速场和海浪场在1973—2002年都存在下降趋势,海浪场的下降趋势更为显著。

Based on ERA-40 data,this paper analyzed the spatial distribution of two modes of wind and wave height of the South China Sea by EOF method,which calculated the spatial distribution,long-term trends and mutation phenomenon of surface wind speed and wave height of South China Sea during 1957—2002.The results showed that the first mode of wind and wave field of South China Sea has a good state of similarity,the second mode has shown different characteristics.Analysis of the first mode of time coefficient also showed that wind and wave height variation has a significant positive correlation and the response of the wave height has certain hysteresis.Wind and wave field during 1973—2002had a downward trend,but the downward trend of wave field was more obvious.