Meridional overturning circulation of the deep Pacific estimated assuming the vertical advective‐diffusive balance
Meridional overturning circulation of the deep Pacific estimated assuming the vertical advective‐diffusive balance
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DOI：
10.1029/2007gl030027
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发表时间：
2007-06
影响因子：
5.2
通讯作者：
T. Endoh;T. Hibiya
中科院分区：
文献类型：
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作者：
T. Endoh;T. Hibiya
假定垂直对流扩散平衡，我们根据观测到的密度场计算了深太平洋的纬向翻转环流。除了密度跃层中穿透扩散率的全球分布外，还考虑了随深度服从高斯分布的底部强化混合。当密度跃层中的透圆扩散率均匀地延伸到底部时，低层绕极深层水（LCDW）穿过赤道向北的输送量仅为1 Sv。当考虑底部强化混合时，垂直翻转环流的增加、减少甚至逆转取决于底辟扩散系数的垂直梯度。向北运输的LCDW穿越赤道成为可比的估计从以前的电流计系泊以及水文调查，只有当混合延伸到粗糙的海底以上，因此，垂直梯度的diapycnal扩散率是小的。
Assuming the vertical advective‐diffusive balance, we calculate the meridional overturning circulation of the deep Pacific based on the observed density field. In addition to the global distribution of diapycnal diffusivity in the pycnocline, bottom‐intensified mixing that follows a Gaussian distribution with depth is taken into account. When diapycnal diffusivity in the pycnocline is assumed to extend uniformly to the bottom, the northward transport of the Lower Circumpolar Deep Water (LCDW) across the equator is only 1 Sv. When the bottom‐intensified mixing is incorporated, the meridional overturning circulation increases, decreases, or even reverses depending on the vertical gradient of diapycnal diffusivity. The northward transport of the LCDW crossing the equator becomes comparable to the estimates from previous current meter moorings as well as hydrographic surveys only when the mixing extends well above the rough ocean bottom and hence the vertical gradient of diapycnal diffusivity is small.