Freshening of Subsurface Waters in the Northwest Pacific Subtropical Gyre: Observations and Dynamics

CORC > 南海海洋研究所 > 中国科学院南海海洋研究所 > 热带海洋环境国家重点实验室(LTO)

	Freshening of Subsurface Waters in the Northwest Pacific Subtropical Gyre: Observations and Dynamics
	[Yan, Youfang ; Qi, Yiquan] Chinese Acad Sci, State Key Lab Trop Oceanog, Guangzhou 510301, Guangdong, Peoples R China ; [Yan, Youfang ; Qi, Yiquan] Chinese Acad Sci, South China Sea Inst Oceanol, Guangzhou 510301, Guangdong, Peoples R China ; [Chassignet, Eric P.] Florida State Univ, Ctr Ocean Atmospher Predict Studies, Tallahassee, FL 32306 USA ; [Chassignet, Eric P. ; Dewar, William K.] Florida State Univ, Dept Earth Ocean & Atmospher Sci, Tallahassee, FL 32306 USA
刊名	JOURNAL OF PHYSICAL OCEANOGRAPHY
	2013
卷号	43 期号:12 页码:2733-2751
ISSN号	0022-3670
通讯作者	youfangyan@scsio.ac.cn
中文摘要	Subsurface salinity anomalies propagating between mid- and low latitudes along isopycnal surfaces have been shown to play an important role in modulating ocean and climate variability. In this study, a sustained freshening and southwestward propagation of subsurface salinity anomalies in the northwest Pacific subtropical gyre and its dynamical mechanism are investigated using observations, numerical outputs, and a predictive model. Analyses of the observations show a pronounced subsurface freshening with salinity decreasing about 0.25 PSU near the 24.5-sigma surface in the northwest Pacific subtropical gyre during 2003-11. This freshening is found to be related to the surface forcing of salinity anomalies in the outcrop zone (25 degrees-35 degrees N, 130 degrees-160 degrees E). A predictive model based on the assumption of salinity conservation along the outcrop isopycnals is derived and used to examine this surface-forcing mechanism. The resemblance between the spatial structures of the subsurface salinity derived from the predictive model and from observations and numerical outputs suggests that subsurface salinity anomalies are ventilated over the outcrop zone. A salinity anomaly with an amplitude of about 0.25 PSU generated by the surface forcing is subducted in the outcrop zone and then propagates southwestward, accompanied by potential vorticity anomalies, to the east of Luzon Strait (similar to 15 degrees N) in roughly one year. When the anomalies reach 15 degrees N, they turn and move gradually eastward toward the central Pacific, associated with an eastward countercurrent on the southern subtropical gyre.
学科主题	Oceanography
资助信息	We thank the JPL ECCO team for providing the Kalman filter assimilation product. Thanks are also given to the anonymous reviewers for their constructive and helpful comments. This work is partly supported by the National Basic Research Program of China (2011CB403504; 2013CB430301) and the National Natural Science Foundation (NSF) of China (41276025). EPC is supported by ONR Contract N00014-09-1-0587. WKD is supported by NSF Grants OCE-100090 and OCE-100743. This work was performed at COAPS on a Chinese Academy of Science Overseas Fellowship.
原文出处	AMER METEOROLOGICAL SOC
语种	英语
WOS记录号	WOS:000327812900015
公开日期	2015-01-14
内容类型	期刊论文
源URL	[http://ir.scsio.ac.cn/handle/344004/10866]
专题	南海海洋研究所_热带海洋环境国家重点实验室(LTO)
推荐引用方式 GB/T 7714	[Yan, Youfang,Qi, Yiquan] Chinese Acad Sci, State Key Lab Trop Oceanog, Guangzhou 510301, Guangdong, Peoples R China,[Yan, Youfang,et al. Freshening of Subsurface Waters in the Northwest Pacific Subtropical Gyre: Observations and Dynamics[J]. JOURNAL OF PHYSICAL OCEANOGRAPHY,2013,43(12):2733-2751.
APA	[Yan, Youfang.,Qi, Yiquan] Chinese Acad Sci, State Key Lab Trop Oceanog, Guangzhou 510301, Guangdong, Peoples R China.,[Yan, Youfang.,Qi, Yiquan] Chinese Acad Sci, South China Sea Inst Oceanol, Guangzhou 510301, Guangdong, Peoples R China.,[Chassignet, Eric P.] Florida State Univ, Ctr Ocean Atmospher Predict Studies, Tallahassee, FL 32306 USA.,...&Dewar, William K.] Florida State Univ, Dept Earth Ocean & Atmospher Sci, Tallahassee, FL 32306 USA.(2013).Freshening of Subsurface Waters in the Northwest Pacific Subtropical Gyre: Observations and Dynamics.JOURNAL OF PHYSICAL OCEANOGRAPHY,43(12),2733-2751.
MLA	[Yan, Youfang,et al."Freshening of Subsurface Waters in the Northwest Pacific Subtropical Gyre: Observations and Dynamics".JOURNAL OF PHYSICAL OCEANOGRAPHY 43.12(2013):2733-2751.