Spatial Distribution of Diffusivity Coefficients and the Effects on Water Mass Modification in the North Pacific
Spatial Distribution of Diffusivity Coefficients and the Effects on Water Mass Modification in the North Pacific
复制标题
北太平洋扩散系数的空间分布及其对水体变化的影响
DOI：
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
S. Kouketsu
中科院分区：
文献类型：
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作者：
S. Kouketsu
基于ARGOfi燕麦阵列在中性密度(C)表面获得的长期平均盐度分布(2001年至2015年)，估计了三维速度、昼夜混合和等天混合fl场。估计的强等天混合与黑潮延伸、副热带边界和北美西海岸有关，而估计的日混合与伊豆-小川脊线和夏威夷海脊有关，这两个海脊是内部造波点。混合系数fi的分布模式与以前用其他方法估计的一致。我们使用混合系数ficientfi场来揭示等水平层上体积输送和盐度收支的空间格局。与厚度扩散率相关的相对较大的涡旋输送对体积输送的空间格局有贡献，而空间变化对昼夜混合的贡献很小。昼夜混合的空间变化对盐度的影响很大，特别是在北太平洋fic中层(26.5-27.0c和27.0-27.5c)附近，而等天混合的空间变化对所有层的水团Modifi阳离子都是重要的。这一分析表明，由于局部强烈的昼夜混合和等天混合，沿黑潮延伸区域形成的明显盐度最低值减弱。尽管研究结果支持利用水体性质的空间分布来推断水团Modifi阳离子的效用，但仍需要基于混合的直接测量和fi尺度参数的评估来澄清混合对水团Modifi阳离子的局域效应，因为本研究的反演误差不足以检测高分辨率的空间变化。
Three-dimensional velocity, diapycnal mixing, and isopycnal mixing fields were estimated based on long-term mean (2001–2015) salinity distributions obtained with Argo float arrays on neutral-density ( c ) surfaces. Strong estimated isopycnal mixings were associated with the Kuroshio Extension, subtropical boundary, and the west coast of North America, and strong estimated diapycnal mixing was associated with the Izu-Ogasawara and Hawaiian ridges, which are internal wave-generation spots. Patterns of the mixing coefficient distributions were consistent with previous estimates by other methods. We used the mixing coefficient fields to reveal the spatial patterns of volume transports and salinity budgets on isopycnal layers. Whereas relatively large eddy transports associated with thickness diffusivity contributed to the spatial patterns of volume transports, the contributions of spatial changes in diapycnal mixing were small. Spatial changes of diapycnal mixing strongly affected those of salinity, especially in the layers around North Pacific Intermediate Water (26.5–27.0 c and 27.0–27.5 c ), whereas spatial changes of isopycnal mixing were important for water mass modification in all layers. This analysis suggests that the clear salinity minimum formed regionally along the Kuroshio Extension decays because of locally strong diapycnal mixing as well as isopycnal mixing. Although the results support the utility of using the spatial distributions of water properties to infer water mass modifications, assessments based on direct measurements of mixing and finescale parameterization are needed to clarify the localized effects of mixing on water mass modifications because the inversion errors in this study were not small enough to enable detection of high-resolution spatial changes.
影响因子：
0.5
作者：
Badin G
通讯作者：
Badin G