Study on three dimensional structure of high and mid-latitude ocean circulation under idealized situation

理想情况下中高纬度海洋环流三维结构研究

• 批准号: 12640416
• 负责人: KUBOKAWA Atsushi
• 金额: $ 1.6万
• 依托单位: HOKKAIDO UNVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12640416/
• 关键词: Ocean circulation; Ventilated thermocline; Eastern boundary; Vertical density diffusion; Planetary waves; Oceanic response; 海洋循環; 海洋水温躍層; 東岸境界層; 海洋循環の応答; 惑星波動

Numerical experiments using an idealized OGCM were carried out to investigate the three dimensional structure of ocean circulation. The model ocean was driven by both wind and surface buoyancy forcing, and deep water formation in the southern hemisphere was included. The results show that the eastern boundary is a source of subsurface water : the water subducted at the eastern boundary flows equatorward along the boundary and then turns westward into the oceanic interior region. This equatorward flow occurs without wind forcing. The analysis based on the potential vorticity balance suggests that the vertical density diffusion is important for generating this current. Sensitivity study of the model results to the vertical diffusion and a theoretical study based on a linear model were also carried out to confirm this idea.In addition to the above work, linear planetary wave dynamics in a 2.5-layer ventilated thermocline model was theoretically investigated to consider the oceanic thermocline variability. After describing the local properties of the waves, wave propagation in a oceanic gyre and oceanic response to atmospheric forcings were discussed. Effects of finite wave length on the wave properties and stabilities were also studied.

利用一个理想化的OGCM模式进行了数值试验，研究了海洋环流的三维结构。海洋模型由风和表面浮力驱动，包括南半球的深水形成。结果表明，东边界是地下水的来源：在东边界俯冲的水沿边界向赤道沿着流动，然后转向向西进入海洋内部。这种向赤道的流动在没有风强迫的情况下发生。基于位涡平衡的分析表明，垂直密度扩散是产生该流的重要原因。为了验证这一观点，还对模式结果对垂直扩散的敏感性进行了研究，并对线性模式进行了理论分析，在此基础上，对2.5层通风温跃层模式中考虑海洋温跃层变化的线性行星波动力学进行了理论分析。在描述了波的局部特性之后，讨论了海洋环流中的波传播和海洋对大气强迫的响应。研究了有限波长对波的性质和稳定性的影响。

项目成果

Kubokawa A., S.P.Xie: "Steady response of a ventilated thermocline to enhanced Ekman pumping"Journal of Oceanography. 58(印刷中). (2002)

Kubokawa A.，S.P.Xie：“通风温跃层对增强 Ekman 抽吸的稳定响应”海洋学杂志 58（出版中）。

Kubokawa A., M. Nagakura: "Linear planetary wave dynamics in a 2.5-layer ventilated thermocline model"Journal of Marine Research. 60(印刷中). (2002)

Kubokawa A.，M. Nagakura：“2.5 层通风温跃层模型中的线性行星波动力学”海洋研究杂志 60（出版中）。

Kubokawa, A., M.Nagakura: "Linear planetary wave dynamics in a 2.5-layer ventilated thermocline model"Journal of Marine Research. 60(印刷中). (2002)

Kubokawa, A., M. Nagakura：“2.5 层通风温跃层模型中的线性行星波动力学”海洋研究杂志 60（出版中）。

Sumata, H., A.Kubokawa: "Numerical study of eastern boundary ventilation and its effects on the thermocline structure"Journal of Physical Oceanography. 31. 3002-3019 (2001)

Sumata，H.，A.Kubokawa：“东部边界通风及其对温跃层结构影响的数值研究”物理海洋学杂志。

Kubokawa A., S. P. Xie: "Steady response of a ventilated thermocline to enhanced Ekman pumping"Journal of Oceanography. 58, (in press). (2002)

Kubokawa A.，S.P. Xie：“通风温跃层对增强埃克曼泵的稳定响应”海洋学杂志。