Topographic Influences on the Wind-Driven Exchange between Marginal Seas and the Open Ocean
Topographic Influences on the Wind-Driven Exchange between Marginal Seas and the Open Ocean
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DOI：
10.1175/jpo-d-21-0058.1
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发表时间：
2021-12-01
影响因子：
3.5
通讯作者：
Spall, Michael A.
中科院分区：
文献类型：
--
作者：
Guo, Haihong;Spall, Michael A.
利用数值和解析模式研究了边缘海和开阔洋之间复杂洋脊和岛屿的风驱动交换。该模型被迫由一个稳定的，空间上均匀的北向风应力，旨在代表大规模的，低频风模式的典型的季节性季风在西太平洋。边缘海有一个向东的Ekman输运，边缘海有一个向西的地转流。埃克曼运输和岛链之间的相互作用产生强烈的斜压流沿着岛屿边界与垂直深度的比例与惯性边界层厚度的斜压变形半径。在间隙的通流的特点是最大的运输中心间隙和减少运输向南部和北方的岛链的尖端。一个扩展的岛屿规则理论表明，通流是由集体之间的平衡粘性的边界和东侧边界的岛屿。外流运输主要是平衡的浅电流，进入边缘海沿着其赤道边界。这些岛屿可以阻止一些直接的交换，并导致在边缘海内的风驱动的翻转单元，但这是补偿周围的南部和北方尖的岛链向东纬向急流。岛屿周围的深斜坡、山脊或浅陆架等地形改变了水流的路径，但最终无法限制边缘海和公海之间的总风力交换。
The wind-driven exchange through complex ridges and islands between marginal seas and the open ocean is studied using both numerical and analytical models. The models are forced by a steady, spatially uniform northward wind stress intended to represent the large-scale, low-frequency wind patterns typical of the seasonal monsoons in the western Pacific Ocean. There is an eastward surface Ekman transport out of the marginal sea and westward geostrophic inflows into the marginal sea. The interaction between the Ekman transport and an island chain produces strong baroclinic flows along the island boundaries with a vertical depth that scales with the ratio of the inertial boundary layer thickness to the baroclinic deformation radius. The throughflows in the gaps are characterized by maximum transport in the center gap and decreasing transports toward the southern and northern tips of the island chain. An extended island rule theory demonstrates that throughflows are determined by the collective balance between viscosity on the meridional boundaries and the eastern side boundary of the islands. The outflowing transport is balanced primarily by a shallow current that enters the marginal sea along its equatorward boundary. The islands can block some direct exchange and result in a wind-driven overturning cell within the marginal sea, but this is compensated for by eastward zonal jets around the southern and northern tips of the island chain. Topography in the form of a deep slope, a ridge, or shallow shelves around the islands alters the current pathways but ultimately is unable to limit the total wind-driven exchange between the marginal sea and the open ocean.