摘要
介绍了北赤道流分叉点、南海北部环流的一些研究成果,并就黑潮对南海的影响所作的研究进行了回顾。北赤道流分叉点的位置对于北赤道流系水体疏运变化及在黑潮和MC之间水体、热量、盐度输运的分配中起着重要的作用。北赤道流分叉点位置约在14.6°N上,分叉点位置随深度增加而北移。分叉点有明显的季节变化和年际变化,在春、夏季向南移动,而在秋、冬季则向北移动。年际变化与ENSO现象相关紧密,在El Ni^no事件NEC分叉纬度处于最北端,在La Ni^no事件处于最南端。对于分叉点位置的定量化研究,仍然需要更多的观测结果进行研究。季风和黑潮是影响南海北部环流的两种主要因素。南海北部上层流场主要由广东沿岸流、黑潮入侵流套、东沙海流、南海暖流和吕宋海流组成。除海盆、次海盆尺度环流外,受季风、黑潮和地形等因素的影响,南海表现出多涡结构。通过近些年的卫星观测和数值模拟的结果,人们对南海中尺度涡的认识大大加深,但要想模拟出风应力形成涡的机制,还需要提高风场和模式的分辨率。由于观测资料的限制,对南海流场的垂直结构、以及春-秋季季风转相时期的流场结构等还研究得较少。吕宋海峡水交换是西太平洋对南海影响的主要途径。黑潮在吕宋海峡附近的形变一直是有争议的热点问题,目前对于黑潮入侵有3种观点:(1)认为黑潮经过吕宋海峡形成流套结构,并分离出中尺度涡影响南海流场、水团结构;(2)认为黑潮有一直接分支分离出来进入南海形成黑潮分支;(3)认为吕宋海峡水交换不属于以上两种情况,西太平洋对南海的水团输送另有机制。北赤道流分叉点在对黑潮的水体、热量、盐度输运的分配中起着重要的作用,黑潮对南海北部环流的影响可能与NEC的分叉点位置有关,但目前对NEC的分叉点位置与南海北部环流相关性的研究甚少。最后提出了对未来加强该方面研究的一些展望。
Some achievements from the study of the North Equatorial Current （NEC） bifurcation and the northern circulation of the South China Sea （SCS） are introduced, and the studies on the Kuroshio＇s impact on the SCS are retrospected.
The position of the NEC bifurcation plays an important role in the variability of water transportation of the North Equatorial Current System and the distribution of water mass, heat and salinity between Kuroshio and Mindanao Current （MC）. The bifurcation is located at about 14. 6°N and moves northward with the increasing depth. It shows obvious seasonal and inter-annual variation, shifting southward in spring and summer, and northward in autumn and winter. Its inter-annual variation is closely associated with ENSO events. NEC bifurcation latitude is located at the northernmost during El Nino event, and at the southernmost during La Nina event. More observation is needed for the quantitative research of NEC bifurcation.
The Northern SCS circulation is mostly affected by the monsoon and the Kuroshio. The upper flow field is made up of Guangdong Coastal Current, Loop current, Dongsha Current, SCS Warm Current and Luzon Coastal Current. Besides the basin and sub-basin scale gyres, many mesoscale eddies are resulted in the SCS from the effects of monsoon, Kuroshio and bed topography. Satellite altimetry and numerical simulation in recent years greatly improve the knowledge of the SCS mesoscale eddy. However, to stimulate the eddy formation mechanism by wind stress, the wind field and model resolution should be improved. Because of the limitation of observation, the study on the vertical current structure and current field during the change ofmonsoon in spring-autumn is rather few.
The water exchange of the Luzon Strait （LS） is the main way that the West Pacific influences the SCS. The deformation of the Kuroshio near the LS is a hot issue of dispute. There are three points of view on the Kuroshio intrusion into the SCS. （1） The Kuroshio flows through the LS in the form of a ＂loop＂, which separates mesoscale eddy influencing the structure of the flow field and water mass of the SCS. （2） A branch of the Kuroshio {lows westward into the SCS, which is called the SCS Kuroshio Branch. （3） The water exchange in the LS does not belong to the above two situations, there is another mechanism still unknown. The intrusion of Kuroshio has obvious seasonal variation. The present study believes that the Kuroshio＇s intrusion mainly occur in the winter, its intrusion pattern is affected by its inflow angle, flux, position and the local wind stress. Both local and global numerical model studies have revealed in a varying degree the impact of the Kuroshio on the SCS circulation and even on the world ocean thermohaline circulation. These arguments need more observations to verify.
The North Equatorial Current bifurcation plays an important role in the distributions of the Kuroshio water, heat and salinity, so the impact of the Kuroshio on the northern SCS circulation may be related to the position of NEC divariction. But at present the study on the relation between the NEC bifurcation position and the northern SCS circulation is rather few. Finally, some prospects of future corresponding study are discussed.
出处
《海洋学研究》
2009年第3期74-84,共11页
Journal of Marine Sciences
基金
国家重点基础研究发展计划项目Argo973课题(2007CB816003)
国家自然科学基金资助项目(40976009)
国家科技支撑计划资助项目(2006BAB19B01)
中国大洋矿产资源研究开发协会资助项目(DYXM-115-02-4-02)
关键词
北赤道流
南海环流
黑潮
分叉点
North Equatorial Current
South China Sea circulation
Kuroshio
bifurcation
作者简介
何映晖（1984-），男，湖南道县人，硕士研究生，主要从事物理海洋方面的研究工作。
通讯作者：蔡树群，研究员，Email：caisq@scsio．ac．cn
