Processes contributing to the evolution and destruction of stratification in the Liverpool Bay ROFI
Processes contributing to the evolution and destruction of stratification in the Liverpool Bay ROFI
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DOI：
10.1007/s10236-011-0402-y
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发表时间：
2011-05
期刊：
影响因子：
2.3
通讯作者：
E. Howlett;T. Rippeth;J. Howarth
中科院分区：
文献类型：
--
作者：
E. Howlett;T. Rippeth;J. Howarth
利物浦湾是一个受淡水影响的地区，受到半日和持续的层化周期的影响，是一个长期海岸天文台的所在地。天文台提供了一系列新的数据，其中包括声学多普勒海流剖面仪和高频雷达系统(提供表面海流测量)的垂直速度剖面。将这一数据集与利用淡水浮力项公式中的进展的分析势能模型结合使用，可以评估控制层结的过程。结果表明，计算分层时应采用深度分辨的淡水浮力项。除深度平均应变外，平流也是影响利物浦湾层结的一个重要过程。具体地说，当半日层结发生时，这两项是同相的，而当持久层结发生时，它们是异相的。平流分量的位相及其相对于深度-平均应变的影响被发现是水平密度梯度垂直变化的函数。
Liverpool Bay, a region of freshwater influence subject to semi-diurnal and enduring periods of stratification, is home to a long-term coastal observatory. The observatory provides a new array of data which include vertical profiles of velocity from an Acoustic Doppler Current Profiler and a high frequency radar system (which provides measurements of surface currents). Using this dataset in conjunction with an analytical potential energy model that uses advances in the formulation of a freshwater buoyancy term, the processes controlling stratification can be assessed. The results indicate that a depth-resolving freshwater buoyancy term should be used for the calculation stratification. Advection, in addition to depth-mean straining, is an important process affecting the stratification in Liverpool Bay. Specifically, when semi-diurnal stratification occurs, the two terms are in phase whilst when enduring stratification occurs, they are out of phase. The phase of the advective component, and thus its influence relative to depth-mean straining, was found to be a function of the vertical variation of the horizontal density gradient.