1979-2018年长江口及邻近海域风速和波高的分布特征与变化趋势

Distribution and variation trend of wind speed and wave height in the Yangtze Estuary and adjacent seas from 1979 to 2018

本文基于欧洲中期天气预报中心(ECMWF)的ERA5与ERA-Interim再分析资料,提取长江口及其邻近海域1979-2018年间共40年的风场和海浪场数据,探讨该海域风浪和波高的时空变化特征,EOF经验正交函数分解法分析结果显示风速与波高的数值在外海普遍高于近岸,且符合长江口所在东海海域受盛行东亚季风影响的特征。Mann-Kendall检验法分析结果显示,在1979-2018年间该海域海表面年均风速呈增长趋势,平均增长速率为0.228 cm/(s·a),累计增长1.6%;年均有效波高呈增长趋势,平均增长速率为0.120 cm/a,累计增长5.4%;年风速和波高的极端值也呈不同程度的增长趋势。

Based on ERA5 and ERA-Interim Reanalysis data of ECMWF, sea surface wind and wave field datasets in the Yangtze Estuary and adjacent seas from 1979 to 2018 are extracted out. By using EOF method, the spatial distribution of wind speed and significant wave height and statistical of their seasonal variation are analyzed. Results found that wind speed and wave height in open seas were generally higher than in nearshore areas, and were consistent with the truth that climate of the East China Sea is controlled by the East Asian Monsoon circulation. The Mann-kendall is used to analyze the variation trend of wind speed and wave height. Results found that the sea surface wind speed in the research area had an obvious increasing trend as a whole by 1.6 % during the recent 40 years, of about 0.228 cm/(s·a) and significant wave height had an obvious increasing trend as a whole by 5.4 % during the 40 years, of about 0.120 cm/a. In addition, wind speed and wave height showed different levels of increasing trend in extreme conditions.