Ocean circulation under idealized conditions and effects of meso-scale eddies

为了了解理想构形下的海洋环流动力学，我们进行了以下三个方面的研究：1.涡分辨模式中的海洋环流--采用反对称Ekman泵驱动的两层准地转模式，当惯性边界层厚度为实际厚度，粘性西部边界层为粘性时，不是很薄，以及一个单一的东射流沿着的涡旋间边界的解决方案。双急流解的偏东急流纬度对参数不敏感，强烈依赖于风强迫的纬向廓线。2.理想海洋GCM中的上层海洋结构--”以混合层深度锋（MLD）为研究对象，研究了MLD的分布和低PV水的俯冲作用。发现MLD锋沿着一条曲线出现，在该曲线上，上层地转流平行于露头流动。在MLD前缘俯冲的水不穿过露头，不同于通风温跃层理论的预期。还研究了季节变化强迫对MLD分布的影响。3.海底地形的影响：结果表明，在高纬斜坡上，西边界流的质量输送在弱风季节与年平均Sverdrup输送基本一致，而在强风季节与瞬时Sverdrup输送基本一致;如果我们将输运定义为从海岸到水流方向改变点的综合水流。研究了一维周期地形上的Rossby波。

In order to understand the ocean circulation dynamics in idealized configurations, we carried out the following three studies.1.Ocean circulation in an eddy-resolving model-Adopting a two-layer quasigeostrophic model driven by anti-symmetric Ekman pumping, a numerical solution with double eastward jets which are prematurely separated from the western boundary was obtained when the inertial boundary layer thickness is realistic and viscous western boundary layer is not very thin, as well as a solution with a single eastward jets along the inter-gyre-boundary. The latitude of the eastward jet of double-jet solution is insensitive to parameters, and strongly depends on the meridional profile of the wind forcing. A parameter region where both the single-jet and double-jet solutions coexist was found.2.Upper-layer ocean structure in an idealized ocean GCM-" Focusing on the mixed-layer depth (MLD) front, we investigated the MLD distribution and subduction of low PV water. It was found that the MLD front occurs along a curve where the upper-layer geostrophic current flows parallel to outcrops. The water subducted at the MLD front does not cross the outcrop, different from that expected from the ventilated thermocline theory. The effect of seasonally variable forcing on the MLD distribution was also investigated.3.Effects of bottom topography: It was found that the mass transport of a western boundary current over a slope in high latitude almost coincides with the annual mean Sverdrup transport in a weak wind season, while it coincides with instantaneous Sverdrup transport in strong wind season, if we define the transport as the integrated current from the coast to a point where the current direction changes. Rossby waves over a one-dimensional periodic topography were also investigated.