Diagnosing the Southern Ocean Overturning from Tracer Fields
Diagnosing the Southern Ocean Overturning from Tracer Fields
复制标题
从示踪场诊断南大洋翻转
DOI：
10.1175/2009jpo4052.1
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发表时间：
2009
影响因子：
3.5
通讯作者：
T. McDougall
中科院分区：
文献类型：
--
作者：
J. Zika;B. Sloyan;T. McDougall
摘要通过对南半球纬向翻转环流（SMOC）的示踪剂场和密度场的水文气候分析，发现SMOC的强度和结构与沿等密度线和垂直方向的混合系数有关。本文用沿等密度线（K）和沿贯向（D）的示踪扩散系数以及沿等密度线的位涡混合系数（KPV）表示绕极上层深水（UCDW）通过南极绕极流（ACC）的纬向输送。均匀的沿等密度线（<600 m2 s−1）和低垂直混合（10−5 m2 s−1）可以维持向南输送小于60 Sv（Sv = 106 m2 s−1）的UCDW穿过ACC，主要分布在南太平洋和东印度洋海盆。对于O（10−4 m2 s−1）或更大的垂直混合速率，推断的输送显著增强。从示踪剂和密度分布推断的输运表明，特别是在较深的层中，K与D的比值为O（2 × 106）。
Abstract The strength and structure of the Southern Hemisphere meridional overturning circulation (SMOC) is related to the along-isopycnal and vertical mixing coefficients by analyzing tracer and density fields from a hydrographic climatology. The meridional transport of Upper Circumpolar Deep Water (UCDW) across the Antarctic Circumpolar Current (ACC) is expressed in terms of the along-isopycnal (K) and diapycnal (D) tracer diffusivities and in terms of the along-isopycnal potential vorticity mixing coefficient (KPV). Uniform along-isopycnal (<600 m2 s−1) and low vertical mixing (10−5 m2 s−1) can maintain a southward transport of less than 60 Sv (Sv = 106 m2 s−1) of UCDW across the ACC, which is distributed largely across the South Pacific and east Indian Ocean basins. For vertical mixing rates of O(10−4 m2 s−1) or greater, the inferred transport is significantly enhanced. The transports inferred from both tracer and density distributions suggest a ratio K to D of O(2 × 106) particularly on deeper layers...