The shallow meridional overturning circulation in the South China Sea and the related internal water movement

doi:10.1007/s13131-016-0900-3

	The shallow meridional overturning circulation in the South China Sea and the related internal water movement
	Zhang Ningning 1; Lan Jian 1; Ma Jie 1; Cui Fengjuan 2
刊名	ACTA OCEANOLOGICA SINICA
	2016-07
卷号	35 期号:7 页码:1-7
关键词	South China Sea shallow meridional overturning circulation Ekman transport subduction upwelling
ISSN号	0253-505X
DOI	10.1007/s13131-016-0900-3
英文摘要	The structure of the annual-mean shallow meridional overturning circulation (SMOC) in the South China Sea (SCS) and the related water movement are investigated, using simple ocean data assimilation (SODA) outputs. The distinct clockwise SMOC is present above 400 m in the SCS on the climatologically annual-mean scale, which consists of downwelling in the northern SCS, a southward subsurface branch supplying upwelling at around 10A degrees N and a northward surface flow, with a strength of about 1x10(6) m(3)/s. The formation mechanisms of its branches are studied separately. The zonal component of the annual-mean wind stress is predominantly westward and causes northward Ekman transport above 50 m. The annual-mean Ekman transport across 18A degrees N is about 1.2x10(6) m(3)/s. An annual-mean subduction rate is calculated by estimating the net volume flux entering the thermocline from the mixed layer in a Lagrangian framework. An annual subduction rate of about 0.66x10(6) m(3)/s is obtained between 17A degrees and 20A degrees N, of which 87% is due to vertical pumping and 13% is due to lateral induction. The subduction rate implies that the subdution contributes significantly to the downwelling branch. The pathways of traced parcels released at the base of the February mixed layer show that after subduction water moves southward to as far as 11A degrees N within the western boundary current before returning northward. The velocity field at the base of mixed layer and a meridional velocity section in winter also confirm that the southward flow in the subsurface layer is mainly by strong western boundary currents. Significant upwelling mainly occurs off the Vietnam coast in the southern SCS. An upper bound for the annual-mean net upwelling rate between 10A degrees and 15A degrees N is 0.7x10(6) m(3)/s, of which a large portion is contributed by summer upwelling, with both the alongshore component of the southwest wind and its offshore increase causing great upwelling.
资助项目	Ministry of Education of China[113041A]
WOS关键词	NORTH-ATLANTIC ; DECADAL VARIABILITY ; OCEAN ; REANALYSIS ; VENTILATION ; PACIFIC ; HEAT
WOS研究方向	Oceanography
语种	英语
出版者	SPRINGER
WOS记录号	WOS:000380153000001
内容类型	期刊论文
源URL	[http://ir.fio.com.cn:8080/handle/2SI8HI0U/25027]
专题	自然资源部第一海洋研究所
通讯作者	Lan Jian
作者单位	1.Ocean Univ China, Coll Phys & Environm Oceanog, Phys Oceanog Lab, Qingdao 266100, Peoples R China 2.State Ocean Adm, North China Sea Branch, North China Sea Data & Informat Serv, Qingdao 266061, Peoples R China
推荐引用方式 GB/T 7714	Zhang Ningning,Lan Jian,Ma Jie,et al. The shallow meridional overturning circulation in the South China Sea and the related internal water movement[J]. ACTA OCEANOLOGICA SINICA,2016,35(7):1-7.
APA	Zhang Ningning,Lan Jian,Ma Jie,&Cui Fengjuan.(2016).The shallow meridional overturning circulation in the South China Sea and the related internal water movement.ACTA OCEANOLOGICA SINICA,35(7),1-7.
MLA	Zhang Ningning,et al."The shallow meridional overturning circulation in the South China Sea and the related internal water movement".ACTA OCEANOLOGICA SINICA 35.7(2016):1-7.