The role of turbulence in the sedimentation loss of pelagic aggregates from the mixed layer
The role of turbulence in the sedimentation loss of pelagic aggregates from the mixed layer
复制标题
湍流在混合层中上层聚集体沉降损失中的作用
DOI：
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发表时间：
1996
期刊：
影响因子：
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通讯作者：
J. Ruiz
中科院分区：
文献类型：
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作者：
J. Ruiz
提出了一种简单的方法来模拟湍流对混合层中上层颗粒的沉降损失的影响。这种方法是通过将平流扩散方程的解分成两个函数来确定湍流如何影响它们的垂直分布，一个函数用于混合层中的颗粒浓度，另一个函数反映颗粒浓度分布的形状。结果表明，当湍流水平较低时，如果假定混合层中颗粒均匀分布，则会严重低估沉降通量。在许多情况下，在不解决混合层中的垂直尺度的情况下，可以对这种低估进行修正。文中用无量纲数对不能进行修正的情况进行了界定。结果还表明了在颗粒动力学模型中解析垂直尺度的重要性，并进一步支持了湍流是导致海洋中团聚体每日循环的机制的假说。
A simple approach is presented to model the effect that turbulence has on the sedimentation loss of pelagic particles from the mixed layer. The approach consists in determining how turbulence affects their vertical distribution by splitting the solution of the advection-diffusion equation into two functions, one for the concentration of particles in the mixed layer and the other one reflecting the shape of the profile of particle concentration. The results of the paper indicate that the sedimentation flux is seriously underestimated if a uniform distribution of particles is assumed in the mixed layer when turbulence levels are low. A correction to this underestimation is possible in many situations without resolving the vertical scale in the mixed layer. The cases in which the correction cannot be applied are delimited in the paper in terms of dimensionless numbers. The results also demonstrate the importance of resolving the vertical scale in models of particle dynamics and add further support to the hypothesis of turbulence as the mechanism responsible for daily cycles of aggregates in the sea.