Observations and numerical simulations of large‐eddy circulation in the ocean surface mixed layer
Observations and numerical simulations of large‐eddy circulation in the ocean surface mixed layer
复制标题
海面混合层大涡环流观测与数值模拟
DOI：
10.1002/2014gl061637
复制
发表时间：
2014
影响因子：
5.2
通讯作者：
B. Cervantes
中科院分区：
文献类型：
--
作者：
M. Sundermeyer;E. Skyllingstad;J. Ledwell;B. Concannon;E. Terray;Daniel A. Birch;S. Pierce;B. Cervantes
使用扫描、深度分辨率的机载激光雷达，在时间上绘制了两个近表面染料释放的地图，时间尺度为几分钟到几小时，水平方向为1 公里，垂直方向为1-20 米。在这两种情况下，染料演变成一系列卷轴，其主轴大致与风和/或近地表电流对齐。在这两种情况下，滚柱间距也是混合层深度的5-10倍，比朗缪尔环流预期的1-2宽高比要大得多。相似强迫下的大涡数值模拟显示出相似的特征，即使没有斯托克斯漂移强迫。其中一例是由微风驱动的惯性切变引起的大展弦比大涡环流。在第二阶段，先前存在的横向混合层密度梯度提供了主要的强迫。在这两种情况下，大涡结构的增长和由此产生的弥散的强度都高度依赖于强迫的类型。
Two near‐surface dye releases were mapped on scales of minutes to hours temporally, meters to order 1 km horizontally, and 1–20 m vertically using a scanning, depth‐resolving airborne lidar. In both cases, dye evolved into a series of rolls with their major axes approximately aligned with the wind and/or near‐surface current. In both cases, roll spacing was also of order 5–10 times the mixed layer depth, considerably larger than the 1–2 aspect ratio expected for Langmuir cells. Numerical large‐eddy simulations under similar forcing showed similar features, even without Stokes drift forcing. In one case, inertial shear driven by light winds induced large aspect ratio large‐eddy circulation. In the second, a preexisting lateral mixed layer density gradient provided the dominant forcing. In both cases, the growth of the large‐eddy structures and the strength of the resulting dispersion were highly dependent on the type of forcing.