Guangdong Key Laboratory of Ocean Remote Sensing, State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences; Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, China; University of Chinese Academy of Sciences, Beijing, China.
Marine Hydrophysical Institute, Russian Academy of Sciences, 299011 Sevastopol, Russia.
Sci Total Environ. 2020 Nov 1;741:140290. doi: 10.1016/j.scitotenv.2020.140290. Epub 2020 Jun 18.
New evidences provided that the tropical cyclone (TC) Linfa in 2015 induced looping path of Kuroshio invasion into the northeastern South China Sea (NESCS) through the northwestern Luzon Strait (LS), based on the in-situ measurements, satellite data and model output data. This TC-enhanced Kuroshio invasion with low nutrients and denser waters suppressed the TC "Wind Pump" induced upwelling and nutrients uptake, and therefore inhibited the Chlorophyll a concentration (Chl-a) increase from surface to ~50 m in the open ocean of the NESCS. The TC-induced Kuroshio invasion promoted the generation of the strong cyclonic eddy to its left side where weak Ekman Pumping Velocity was observed. This enhancing cyclonic eddy then dominated the nutrients uplift and increased the surface and subsurface (0-50 m) Chl-a through eddy pumping rather than Ekman Pumping. The TC-declined anti-cyclonic eddy, which shoaled the Mixed Layer Depth (MLD), benefited to the nutrient uptake through TC-induced upwelling and thereby increased the surface Chl-a and raised the Chl-a Maximum Layer (CML) to ~20 m over the southwestern LS. The temporal Chl-a variations were also influenced by TC intensities and biochemical processes. The air-sea heat budget analysis indicated that, the air-sea heat exchange contributed to nearly 80% of the sea surface cooling (SST cooling) over the northwestern LS with Kuroshio invasion, while eddy-induced upwelling dominated the SST cooling over the western LS, and the wind-driven upwelling (and mixing) controlled the SST cooling over the southwestern LS. These different formations of SST cooling then played important role in Chl-a variations. This study is the first case of TC "Wind Pump" induced Chl-a variations considering air-sea heat exchange, Kuroshio invasion and mesoscale eddies over LS, which would help to evaluate the influence of TCs over the other major heat transport arteries of the world ocean: The Gulf Stream area.
新的证据表明，2015 年的热带气旋“林发”通过西北吕宋海峡（LS）将黑潮入侵的环流向东北南海（NESCS）诱导，这是基于现场测量、卫星数据和模型输出数据得出的。这种热带气旋增强的黑潮入侵带来了低营养和高密度的水，抑制了热带气旋“风泵”引起的上升流和营养物质的吸收，因此抑制了 NESCS 开阔海域表层到约 50 米深度的叶绿素 a 浓度（Chl-a）的增加。热带气旋引起的黑潮入侵促进了其左侧强气旋性涡旋的产生，在那里观察到较弱的 Ekman 抽吸速度。这个增强的气旋性涡旋通过涡旋抽吸而不是 Ekman 抽吸来支配营养物质的上升，从而增加了表层和次表层（0-50 米）的 Chl-a。热带气旋减弱的反气旋性涡旋，使混合层深度（MLD）变浅，有利于通过热带气旋引起的上升流吸收营养物质，从而增加表层 Chl-a，并将 Chl-a 最大层（CML）提高到 LS 西南部约 20 米。Chl-a 的时间变化也受到热带气旋强度和生化过程的影响。海气热收支分析表明，在黑潮入侵的情况下，LS 西北海域的海气热交换对近 80%的海面冷却（SST 冷却）有贡献，而涡旋引起的上升流主导了 LS 西部的 SST 冷却，风驱动的上升流（和混合）控制了 LS 西南部的 SST 冷却。这些不同形式的 SST 冷却在 Chl-a 的变化中起着重要作用。本研究首次考虑了 LS 上的海气热交换、黑潮入侵和中尺度涡旋，研究了热带气旋“风泵”引起的 Chl-a 变化，这将有助于评估热带气旋对世界海洋其他主要热输送动脉的影响：墨西哥湾流区。
