SURFACE MIXED AND MIXING LAYER DEPTHS
SURFACE MIXED AND MIXING LAYER DEPTHS
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DOI：
10.1016/0967-0637(95)00068-h
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发表时间：
1995-09-01
影响因子：
2.4
通讯作者：
GREGG, MC
中科院分区：
文献类型：
--
作者：
BRAINERD, KE;GREGG, MC
为了了解表面混合层内热储存的日循环，有必要区分混合层和混合层，混合层是由混合历史形成的相对均匀的水的区域，混合层是目前活跃的区域。我们比较表面层定义的基础上密度（或温度）与湍流测量，以评估他们的技能，找到混合和混合层的深度，使用的定义的基础上从表面的密度增加，密度梯度。这两种类型的定义都能够找到混合层深度，并根据当地条件进行调整。然而，这两种定义都不能给出与湍流测量一致的混合层深度，尽管密度差给出了更稳定的结果。湍流耗散率或翻转长度尺度的测量通常会得到一致的混合层深度估计，但也有翻转长度给出明显更好的结果的情况下。我们的结论是，倾覆长度尺度给出了最可靠的测量混合层深度，虽然传统的船载CTD很少能够充分解决倾覆。
In order to understand the daily cycle of heat storage within the surface mixed layer it is necessary to distinguish between the mixed layer, the zone of relatively homogeneous water formed by the history of mixing, and the mixing layer, the zone in which mixing is currently active. We compare surface layer definitions based on density (or temperature) with turbulence measurements to evaluate their skill in finding mixed and mixing layer depths, using definitions based on density increase from the surface, and on density gradients. Both types of definition are capable of finding the mixed layer depth, with some tuning for local conditions. Neither definition, however, gives mixing layer depths consistently matching the turbulence measurements, although density differences give more stable results. Measurements of turbulent dissipation rates or overturning length scales often yield consistent estimates of mixing layer depths, but there are cases where overturning lengths give distinctly better results. We conclude that overturning length scales give the most reliable measure of mixing layer depth, although conventional shipborne CTDs are seldom capable of sufficiently resolving the overturns.