Interannual Variations of the North Equatorial Current Across the Pacific Ocean

doi:10.1029/2023JC020174

IOCAS-IR > 海洋环流与波动重点实验室

	Interannual Variations of the North Equatorial Current Across the Pacific Ocean
	Liu, Xueqi1 ; Zhou, Hui 1,2,3; Liu, Hengchang 4,5
	2024-02-01
发表期刊	JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
ISSN	2169-9275
卷号	129 期号:2 页码:18
通讯作者	Zhou, Hui(zhouhui@qdio.ac.cn)
摘要	The interannual variation of the North Equatorial Current (NEC) across the North Pacific Ocean and the modulation of the Pacific Decadal Oscillation (PDO) are investigated based on both observations and reduced gravity model experiments. Results reveal that the interannual variation of the NEC is highly related to El Nino-Southern Oscillation (ENSO) with unsynchronized variations both in zonal and meridional structure. The tropical and subtropical gyre branches of the NEC (NEC-S and NEC-N) behave antiphase variation during El Nino events with the transport of the former being enhanced and the latter being weakened across the Pacific. The NEC axis in the western/eastern Pacific shifts northward/southward during El Nino events, consistent with the meridional shift of the zero-line of wind stress curl. Model experiments indicate that Rossby waves mainly modulate the NEC near the western boundary and the NEC-N, while Ekman pumping modulates NEC-S in the western basin. Meanwhile, the relationship between the interannual variation of the NEC and ENSO events is significantly modulated by different PDO phases. The PDO cold phase favors a much closer connection between the NEC and the Nino 3.4 index. The dynamics lie in that PDO-related wind stress curl and sea level anomalies are consistent with that of El Nino, favoring the enhanced correlation between NEC and El Nino. The reverse is true for the warm phase. These results will contribute to a better understanding of the behavior of the tropical Pacific Ocean circulation and its role in climate change. Serving as the boundary of tropical and subtropical gyres, the North Equatorial Current plays an important role in the exchanging of mass, heat, and salt between the mid- and low-latitude oceans. It is a very broad current and behaves quite differently in both zonal and meridional directions across the Pacific due to the phase lag of propagated Rossby waves. This study reveals that the interannual variation of the North Equatorial Current is highly related to El Nino-Southern Oscillation (ENSO) with unsynchronized variations in zonal and meridional structure. The tropical and subtropical gyre branches of the North Equatorial Current behave antiphase variation during El Ninos with the transport of the former is enhanced and the latter weakened across the Pacific. Rossby waves excited west of the dateline modulate the North Equatorial Current near the western boundary, while those excited in the eastern Pacific modulate the subtropical branches. Local Ekman pumping plays a dominant role in tropical branches in the western Pacific. Further analysis indicates that the ENSO-related air-sea state in the tropical Pacific Ocean is modulated by Pacific Decadal Oscillation phases. The cold phase favors a much closer connection between the North Equatorial Current and ENSO events. Interannual variation of the North Equatorial Current (NEC) is highly related to El Nino-Southern Oscillation (ENSO) with unsynchronized variations both in zonal and meridional structure Rossby waves mainly modulate the NEC near the western boundary and subtropical gyre branch, while Ekman pumping modulates the tropical gyre branch The relationship between the NEC and ENSO is nonstationary and significantly modulated by different phases of the Pacific Decadal Oscillation
关键词	North Equatorial Current Rossby waves interannual variation ENSO PDO
DOI	10.1029/2023JC020174
收录类别	SCI
语种	英语
资助项目	National Natural Science Foundation of China[42276012] ; National Natural Science Foundation of China (NSFC) project[LSKJ202202502] ; Science and Technology Innovation Project of Laoshan Laboratory[XDB42000000] ; Strategic Priority Research Program of the Chinese Academy of Sciences[42306002] ; NSFC project
WOS研究方向	Oceanography
WOS类目	Oceanography
WOS记录号	WOS:001166369300001
出版者	AMER GEOPHYSICAL UNION
WOS关键词	SOUTHERN-OSCILLATION ; DECADAL VARIABILITY ; MINDANAO CURRENT ; ROSSBY WAVES ; BIFURCATION ; TRANSPORT ; KUROSHIO ; THERMOCLINE ; MODULATION ; ADJUSTMENT
引用统计
文献类型	期刊论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/184575
专题	海洋环流与波动重点实验室
通讯作者	Zhou, Hui
作者单位	1.Chinese Acad Sci, Inst Oceanol, CAS Key Lab Ocean Circulat & Waves, Qingdao, Peoples R China 2.Univ Chinese Acad Sci, Beijing, Peoples R China 3.Laoshan Lab, Qingdao, Peoples R China 4.Beijing Inst Appl Meteorol, Beijing, Peoples R China 5.State Key Lab Geoinformat Engn, Xian, Peoples R China
第一作者单位	中国科学院海洋研究所
通讯作者单位	中国科学院海洋研究所
推荐引用方式 GB/T 7714	Liu, Xueqi,Zhou, Hui,Liu, Hengchang. Interannual Variations of the North Equatorial Current Across the Pacific Ocean[J]. JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS,2024,129(2):18.
APA	Liu, Xueqi,Zhou, Hui,&Liu, Hengchang.(2024).Interannual Variations of the North Equatorial Current Across the Pacific Ocean.JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS,129(2),18.
MLA	Liu, Xueqi,et al."Interannual Variations of the North Equatorial Current Across the Pacific Ocean".JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS 129.2(2024):18.