Decomposition of Vertical Velocity for Nutrient Transport in the Upper Ocean
Decomposition of Vertical Velocity for Nutrient Transport in the Upper Ocean
复制标题
上层海洋营养物输送的垂直速度分解
DOI：
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发表时间：
2019
影响因子：
3.5
通讯作者：
A. Mahadevan
中科院分区：
文献类型：
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作者：
M. Freilich;A. Mahadevan
在密度跃层中，其中的穿透混合被抑制，无论是垂直运动（隆起）的等密度面和向上运动沿着倾斜的等密度线提供营养物质的真光层，但这些机制的相对重要性是未知的。本文提出了一种在拉格朗日坐标系中将垂直速度w分解为两个分量的方法：沿沿着倾斜等密面的垂直速度和等密面的绝热垂直速度。我们表明，其中是等密度线斜率，是流动的几何纵横比，并且对于代表中纬度密度跃层的等密度线斜率，它占总垂直速度w的10%-25%。我们进行分解的w在一个过程中的研究模式的中纬度涡旋流场产生的等密度线的斜率范围。速度分量的谱分解表明，虽然是垂直速度的最大贡献者，在水平尺度小于约10公里，也就是说，在中尺度下，是相当的大小。增加模型的水平网格分辨率已知会增加垂直速度;这种增加不成比例地归因于更好的分辨率，如这里通过比较1公里和4公里分辨率的模型运行所示。沿等密度线的垂直输送可以是一个重要的贡献者的示踪剂，包括氧气，营养物质和叶绿素的垂直通量，虽然我们发现弱协方差之间的垂直速度和营养异常在我们的模型。
Within the pycnocline, where diapycnal mixing is suppressed, both the vertical movement (uplift) of isopycnal surfaces and upward motion along sloping isopycnals supply nutrients to the euphotic layer, but the relative importance of each of these mechanisms is unknown. We present a method for decomposing vertical velocity w into two components in a Lagrangian frame: vertical velocity along sloping isopycnal surfaces and the adiabatic vertical velocity of isopycnal surfaces . We show that , where is the isopycnal slope and is the geometric aspect ratio of the flow, and that accounts for 10%–25% of the total vertical velocity w for isopycnal slopes representative of the midlatitude pycnocline. We perform the decomposition of w in a process study model of a midlatitude eddying flow field generated with a range of isopycnal slopes. A spectral decomposition of the velocity components shows that while is the largest contributor to vertical velocity, is of comparable magnitude at horizontal scales less than about 10 km, that is, at submesoscales. Increasing the horizontal grid resolution of models is known to increase vertical velocity; this increase is disproportionately due to better resolution of , as is shown here by comparing 1- and 4-km resolution model runs. Along-isopycnal vertical transport can be an important contributor to the vertical flux of tracers, including oxygen, nutrients, and chlorophyll, although we find weak covariance between vertical velocity and nutrient anomaly in our model.
影响因子：
16.6
作者：
Su Z;Wang J;Klein P;Thompson AF;Menemenlis D
通讯作者：
Menemenlis D