Relationship between a function of the northward pressure gradient and the Pacific Equatorial Undercurrent

CHEN Xuan; ZHENG Chongwei; WU Hui; YOU Xiaobao; LI Xunqiang; WANG Huipeng

doi:10.1007/s13131-018-1262-9

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CHEN Xuan, ZHENG Chongwei, WU Hui, YOU Xiaobao, LI Xunqiang, WANG Huipeng. Relationship between a function of the northward pressure gradient and the Pacific Equatorial Undercurrent[J]. Acta Oceanologica Sinica, 2018, 37(9): 22-28. doi: 10.1007/s13131-018-1262-9

Citation:

CHEN Xuan, ZHENG Chongwei, WU Hui, YOU Xiaobao, LI Xunqiang, WANG Huipeng. Relationship between a function of the northward pressure gradient and the Pacific Equatorial Undercurrent[J]. Acta Oceanologica Sinica, 2018, 37(9): 22-28. doi: 10.1007/s13131-018-1262-9

Citation:

CHEN Xuan, ZHENG Chongwei, WU Hui, YOU Xiaobao, LI Xunqiang, WANG Huipeng. Relationship between a function of the northward pressure gradient and the Pacific Equatorial Undercurrent[J]. Acta Oceanologica Sinica, 2018, 37(9): 22-28. doi: 10.1007/s13131-018-1262-9

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Relationship between a function of the northward pressure gradient and the Pacific Equatorial Undercurrent

doi: 10.1007/s13131-018-1262-9

1.
The 75839 Army, People's Liberation Army, Guangzhou 510510, China;State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China;Beijing Institute of Applied Meteorology, Beijing 100029, China
2.
State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China;Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China;State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, the Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China;Beijing Institute of Applied Meteorology, Beijing 100029, China
3.
State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China
4.
Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China;Beijing Institute of Applied Meteorology, Beijing 100029, China
5.
College of Meteorology and Oceanography, National University of Defense Technology, Nanjing 211101, China
6.
The 75839 Army, People's Liberation Army, Guangzhou 510510, China

Received Date: 2017-03-11

Abstract

Abstract

The Equatorial Undercurrent (EUC) plays an important role in ocean circulation and global climate change. Near the equator, as the Coriolis parameter goes to 0, equatorial currents cannot be described by geostrophy in which the pressure gradient force term is balanced by the Coriolis force term. Many previous studies focus on the relationships between the EUC and El Niño-Southern Oscillation (ENSO), the thermocline, sea surface topography, the distribution of equatorial wind stress and other atmosphere-ocean factors. However, little attention has been paid to the northward pressure gradient (NGT), which may also be important to the EUC. The pressure can be regarded as a complex nonlinear function of terms including temperature, salinity and density. This study attempts to reveal the connection between a function of the northward pressure gradient (FNP) and the EUC. The connection is derived from primitive equations, by simplifying the equations with using scaling analysis, and shows that the beta effect may be the main reason why the FNP is important to the EUC. The vertical structure of the EUC can be partially described by the FNP. The NGT has an obvious influence on the EUC while the eastward pressure gradient has a relatively smaller effect.
- Equatorial Undercurrent,
- northward pressure gradient,
- beta effect

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References(29)

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