超强台风“威马逊”对南海西北海域海洋环境的影响

The impacts of super typhoon Rammasun on the environment of the northwestern South China Sea

2014年第9号超强台风"威马逊"(1409)过境南海并穿越琼州海峡进入北部湾,给海南、广东和广西造成了严重损失,并对南海西北海域海洋动力与生态环境产生了重要的影响。文章利用卫星遥感水色水温及风场数据,分析了台风前后海表温度、悬浮泥沙浓度、叶绿素浓度、初级生产力及上升流分布特征与变化。研究结果表明:超强台风"威马逊"诱发了强烈的混合夹卷和上升流,并加强了季节性上升流;海表温度最大降幅近2℃,相对台风路径呈显著的"右偏性",而台风引起的强降水却具强烈的"左偏性";台风后悬浮泥沙浓度平均升高51.4%,叶绿素浓度增幅达28%,且最大浓度有3d的延迟,初级生产力增加34%;上层水体混合加剧,混合层深度平均增长近10.4m。

Super Typhoon Rammasun (1409) in 2014 crossed the South China Sea and the Qiongzhou Strait, and then entered the Beibu Gulf. It caused great losses in Hainan, Guangdong and Guangxi, and had a great impact on the northern South China Sea. We analyzed distribution features and changes of sea surface temperature (SST), chlorophyll concentration, primary productivity, suspended sediment concentration, and upwelling before and after the typhoon, using the satellite remote sensing data of ocean color, SST and wind fields of the same period. We found that Super Typhoon Ramasun induced strong entrainment and upwelling, and strengthened the seasonal upwelling. The maximum cooling near 2℃ had a clear “righthand-side intensification,” while the heavy rainfall had significant “left-hand-side intensification” with respect to the typhoon track. After the typhoon, the average concentration of suspended sediment increased 51.4%, and then the chlorophyll concentration increased 28% with its maximum delayed by 3 d and the primary productivity increased by 34%. The upper layer mixing intensified with average mixed layer depth increase of nearly 10.4 m.