The zonal momentum balance in an eddy‐resolving general‐circulation model of the southern ocean
The zonal momentum balance in an eddy‐resolving general‐circulation model of the southern ocean
复制标题
南大洋涡旋大气环流模型中的纬向动量平衡
DOI：
10.1002/qj.49712354008
复制
发表时间：
1997
影响因子：
8.9
通讯作者：
V. Ivchenko
中科院分区：
文献类型：
--
作者：
D. Stevens;V. Ivchenko
利用一个涡旋分辨的海洋环流模式（即弗拉姆）对南大洋纬向无界区的动量平衡进行了研究。动量，这是输入在表面和加速南极绕极流，被转移到水柱和地形形状应力。底部摩擦和横向涡动粘性被发现是可以忽略不计的。东向动量的极向通量对动量再分配的影响很小。尽管如此，在风驱动的近地面层之下和地形之上，极向动量通量散度与行星涡度的非地转通量一起沿着提供了主要的平衡（尽管这些项的大小比风应力小一个数量级）。在Ekman层以下，立涡对流动产生阻力，而瞬变涡加速流动。然而，瞬态涡流的影响较小。动量的向下传递通过界面形状应力实现。这可以用极向密度（热）通量来理解。主要贡献来自于立涡，而瞬态涡的贡献较小。这两种捐款都有助于转移。来自邻近海洋（德雷克海峡纬度以北和以南）的密度（热量）通量影响纬向动量的深度穿透，特别是在1000米以上。推广了约翰逊-布莱登理论，给出了一个与Eliassen-Palm横截面相关的剩余环流的流函数成比例的附加项。
The momentum balance in the zonally unbounded region of the Southern Ocean is examined using an eddy‐resolving ocean general‐circulation model (namely FRAM). Momentum, which is input at the surface and accelerates the Antarctic Circumpolar Current, is transferred down the water column and removed by topographic form stress. Bottom friction and lateral eddy viscosity are found to be negligible. the poleward flux of eastward momentum has a small effect in redistributing momentum. In spite of this, below the wind‐driven surface layer and above the level of topography, the poleward momentum‐flux divergence provides the main balance along with the ageostrophic flux of planetary vorticity (although the magnitude of these terms is an order of magnitude smaller than the wind stress). Below the Ekman layer, standing eddies produce a drag on the flow whilst transient eddies accelerate the flow. However, the impact of transient eddies is smaller. the downward transfer of momentum is achieved by interfacial form stress. This can be understood in terms of a poleward density (heat) flux. the main contribution comes from standing eddies, with a smaller contribution from transient eddies. Both contributions assist the transfer. the flux of density (heat) from the neighbouring oceans (to the north and south of the Drake Passage latitudes) influences the depth penetration of zonal momentum, particularly in the upper 1000 m. the Johnson‐Bryden theory is generalized to give an additional term which is proportional to the stream function for the residual circulation associated with Eliassen‐Palm cross‐sections.