台风“彩虹”对粤西近岸海表温度和叶绿素浓度的影响

Impacts of Typhoon Mujigea on Sea Surface Temperature and Chlorophyll-a Concentration in the Coastal Ocean of Western Guangdong

利用高分辨率的海表面温度(SST)和叶绿素a浓度数据,分析2015年超强台风"彩虹"对粤西近岸海洋动力环境的影响。结果表明:"彩虹"过境后,粤西海域SST总变化为降温,且台风路径右侧降温高于左侧,最大热损失达到-9×10~6 J/m^3。"彩虹"引起的降温幅度以及最大降温出现时间在不同海区有所不同。珠江口附近海域、珠江口外海200 m等深线附近以及阳江至东海岛沿岸区域在台风登陆后2―4 d形成3个降温中心,最大降温均为-2℃左右。对台风路径两侧近岸、陆架和深水六个区域对比分析发现,近岸SST变化幅度最大,且两侧最大降温时间相同,而陆架和深水区则是左侧降温低于右侧。台风路径左侧雷州半岛以东约100 km和海南岛以东近海的叶绿素a浓度显著增加,最大增幅达5 mg/m^3。

This study analyzes the influence of the super typhoon Mujigea on the coastal ocean of the western Guangdong by using the high-resolution sea surface temperature(SST)data and the chlorophyll-a concentration data.The results indicate that the SST in the studied area generallydecreased after Mujigea passed by.The maximum thermal loss was-9×106J/m3on the right side of the typhoon track.The amplitudes of SST variation and the maximum cooling dates vary in different regions.Three cooling centers with the maximum cooling of-2℃appear in regions near the Parl River estuary,the200m isobaths in the edge of continental shelf off the Pearl River and the coastal areas from Yangjiang to Donghai Island.The maximum cooling appears2-4d after Mujigea’s passage.The SST variation in six regions distributed in near shore,the shelf and the deep water on two sides of the typhoon track are compared.The results show that the decreases of the near-shore SST are the greatest,and the maximum cooling on two sides of typhoon track occurred on the same day.In the shelf and deep waters,the SST variations on the right side of the typhoon track are larger than that on the left side.The maximum cooling on two sides occurred on different dates.The maximum increase of chlorophyll-a concentration caused by typhoon appears in the shelf sea100km east of Leizhou Peninsula and Hainan Island on the left side of typhoon track.The maximum increase reaches5mg/m3.