| 摘要: |
| 根据全球高分辨率的海洋环流模式(POCM)的数值模拟结果,发现北赤道流区上层海洋流的季节内变化是以准60天振荡为主,该准60天振荡的振幅有年际变化。利用2.5层海洋模式,确定了NEC区纬向Rossby波解的频散关系。该关系表明:北赤道流区行星波和波长小于570km的Rossby波都为稳定波;波长小于2000km,大于570km的Rossby为不稳定波;最不稳定波的相速度和波长分别为-0.145m·s-1和785km。斜压不稳定是北赤道流区上层海洋准60天振荡的主要形成机制。
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| 关键词: 北赤道流,长Rossby波,准60天振荡,斜压稳定性,形成机制 |
| DOI：10.11693/hyhz200301012012 |
| 分类号: |
| 基金项目:国家重点基础研究发展规划项目(中国近海环流形成变异机理、数值预测方法及对环境影响的研究) G1999043807号;国家自然科学基金资助项目:49976004号和海外杰出青年基金资助项目:40028605号 |
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| INTRASEASONAL OSCILLATION AND BAROCLINIC INSTABILITY OF UPPER LAYER OCEAN IN THE NORTH EQUATOR CURRENT |
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LIU Qin-Yu, PAN Ai-Jun, LIU Zheng-Yu
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Institute of Physical Oceanography, China Ocean University
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| Abstract: |
| Based on the numerical simulation output data of the global ocean model with high resolution (POCM), a quasi 60-day oscillation of the flow is mainly intraseasonal oscillation in the North Equator Current (NEC) region, and the amplitude of the quasi 60-day oscillation varies on an interannual time scale. Using the baroclinic 2.5 layer ocean model with dissipation, the dispersion relation for the Rossby wave is determined, which shows that in the NEC region the zonal planetary Rossby waves or the Rossby waves with shorter wavelength than 570km are stable; the Rossby waves with wavelengths longer than 570km and shorter than 2000km are instable waves. The phase speed and wavelengh of the most instable waves are -0.145m·s-1 and 785km, respectively. The baroclinic instability is the main formation mechanism of the quasi 60-day oscillation. The reason for the weaker quasi 60-day oscillation of the NEC in the west Pacific during 1997—1998 is discussed too.
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| Key words: North Equator Current, Quasi-60 day oscillation, Baroclinic Instability, Formationmechanism |
