Eddy formation and surface flow field in the Luzon Strait area during the summer of 2009  

作　　者：刘泽 侯一筠 谢强 

机构地区：[1]Key Laboratory of Ocean Circulation and Waves,Institute of Oceanology,Chinese Academy of Sciences [2]State Key Laboratory of Tropical Oceanography,South China Sea Institute of Oceanology,Chinese Academy of Sciences [3]Sanya Institute of Deep-Sea Science and Engineering,Chinese Academy of Sciences

出　　处：《Chinese Journal of Oceanology and Limnology》2015年第5期1320-1333,共14页中国海洋湖沼学报（英文版）

基　　金：Supported by the National Natural Science Foundation of China(Nos.41306019,U1133001);the open grant of LTO SCSIO/CAS(No.LTO201305);the Sanya and CAS Cooperation Project(No.2013YD77);the NSFC Innovative Group(No.41421005);the NSFC-Shandong Joint Fund for Marine Science Research Centers(No.U1406401);the Pilot Strategic Project of CAS(No.XDA11020101);the Knowledge Innovation Engineering Frontier Project of SIDSSE(No.SIDSSE-201205)

摘　　要：The formation of mesoscale eddies and the structure of the surface flow field in the Luzon Strait area were examined using in-situ CTD data, Argo float data, and multi-satellite remote sensing data collected from May to August 2009. The results show that vigorous water exchange between Kuroshio water and South China Sea （SCS） water began to emerge over the 200 m water column throughout the strait. Based on an objective definition of surface currents, float A69 tracked an anti-cyclonic eddy southwest of Taiwan Island under a Lagrangian current measurement. The salinity inside the anti-cyclonic eddy was higher than in typical SCS water but lower than in Kuroshio mainstream water, indicating that this eddy was induced by Kuroshio frontal intrusion through the Luzun Strait and into the SCS. From hydrographic data, we propose that continuous horizontal diffusion with high-salinity characteristics in the subsurface layer could extend to 119°E or even further west. The high-temperature filament, large positive sea level anomaly and clockwise geostrophic current all confirmed the existence of this warm eddy in May and June. A strongly negative wind stress curl maintained the eddy until it died. The surface flow field during July and August was rather complicated. Float A83 described an east-west orientated shuttle run in the 20°N section that was not reported by previous studies. At the same time, float A80 indicated a Kuroshio bend into the north-central region of Luzon Strait but it did not cross 120.5°E. The water mass rejoining the Kuroshio mainstream from the southern tip of Taiwan Island was less saline, indicating an entrainment of water from SCS by the Kuroshio bend.The formation of mesoscale eddies and the structure of the surface flow field in the Luzon Strait area were examined using in-situ CTD data,Argo float data,and multi-satellite remote sensing data collected from May to August 2009. The results show that vigorous water exchange between Kuroshio water and South China Sea(SCS) water began to emerge over the 200 m water column throughout the strait. Based on an objective definition of surface currents,float A69 tracked an anti-cyclonic eddy southwest of Taiwan Island under a Lagrangian current measurement. The salinity inside the anti-cyclonic eddy was higher than in typical SCS water but lower than in Kuroshio mainstream water,indicating that this eddy was induced by Kuroshio frontal intrusion through the Luzon Strait and into the SCS. From hydrographic data,we propose that continuous horizontal diffusion with high-salinity characteristics in the subsurface layer could extend to 119°E or even further west. The high-temperature filament,large positive sea level anomaly and clockwise geostrophic current all confirmed the existence of this warm eddy in May and June. A strongly negative wind stress curl maintained the eddy until it died. The surface flow field during July and August was rather complicated. Float A83 described an east-west orientated shuttle run in the 20°N section that was not reported by previous studies. At the same time,float A80 indicated a Kuroshio bend into the north-central region of Luzon Strait but it did not cross 120.5°E. The water mass rejoining the Kuroshio mainstream from the southern tip of Taiwan Island was less saline,indicating an entrainment of water from SCS by the Kuroshio bend.

关 键 词：mesoscale eddy surface flow field hydrographic data Argo trajectory Argo profile Luzon Strait 

分 类 号：P731.2[天文地球—海洋科学]