Intensified turbulent mixing in the boundary current system of southern Greenland
Intensified turbulent mixing in the boundary current system of southern Greenland
复制标题
格陵兰岛南部边界流系统中的强化湍流混合
DOI：
10.1029/2007gl032785
复制
发表时间：
2008
影响因子：
5.2
通讯作者：
N. P. Holliday
中科院分区：
文献类型：
--
作者：
J. Lauderdale;S. Bacon;A. N. Naveira Garabato;N. P. Holliday
格陵兰南部深层西部边界流(DWBC)平流了北大西洋深水的主要组成部分。∼10−4m2 S−1的湍流昼夜混合率在赤道对流层中较为常见。这些扩散系数是用基于内波应变的参数估计的，由密度和溶解氧的预算独立确认。“中等”混合率(∼10−4 m2 S−1)在丹麦海峡至法雷韦尔角(∼1 000公里)之间的热带气旋路径(∼10−4 m2 S−1)上，通过昼夜夹带到更强(∼10−3 m2 S−1)的局地混合率，驱动着类似的净输送增加。因此，与丹麦海峡以南的DWBC有关的湍流混合对确定北大西洋经向翻转环流的量级起到了重要作用。在格陵兰东部和西部洋流中也可以看到混合速率的提高；这可能对伊尔明格盆地和拉布拉多盆地中间层的预适应季节性再分层具有重要意义。
The southern Greenland Deep Western Boundary Current (DWBC) advects major components of North Atlantic Deep Water. Turbulent diapycnal mixing rates of ∼10−4 m2 s−1 commonly occur in the DWBC. These diffusivities, estimated with an internal wave strain‐based parameterisation, are independently confirmed by budgets of density and dissolved O2. “Moderate” mixing rates (∼10−4 m2 s−1) over the DWBC path between Denmark Strait and Cape Farewell (∼1000 km) drive a similar net increase in volume transport by diapycnal entrainment to the more intense (∼10−3 m2 s−1), localised mixing rates found near the Denmark Strait overflow sill. Therefore turbulent mixing associated with the DWBC south of Denmark Strait is instrumental in establishing the magnitude of the North Atlantic Meridional Overturning Circulation. Elevated mixing rates are also seen in the East and West Greenland Currents; this may be significant in preconditioning seasonal restratification of the intermediate layers of the Irminger and Labrador basins.