Shelf sea tidal currents and mixing fronts determined from ocean glider observations
Shelf sea tidal currents and mixing fronts determined from ocean glider observations
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根据海洋滑翔机观测确定的陆架海潮流和混合锋
DOI：
10.5194/os-14-225-2018
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发表时间：
2017
期刊：
影响因子：
3.2
通讯作者：
B. Queste
中科院分区：
文献类型：
--
作者：
P. Sheehan;B. Berx;A. Gallego;R. Hall;K. Heywood;S. Hughes;B. Queste
抽象的。潮汐和潮汐混合锋对于
了解大陆架海洋动力学和生态系统。海洋滑翔机使
以高分辨率观测锋面和潮汐主导流。我们使用
2个月（2013年10月12日至12月2日）滑翔机的潜水平均海流
沿着北海西北部的带状水文剖面部署
精确测定M2和S2潮汐速度。的结果
基于滑翔机方法与海流测量的潮汐速度吻合良好
米和速度提取的TPXO潮汐模型。述的方法
提高了滑翔机作为海洋观测平台的实用性，特别是
在已知潮汐模型有限的区域中。然后我们使用
滑翔机得出的潮汐速度，以调查潮汐控制的位置
滑翔机反复观察的锋面。锋面向外海移动，
0.51公里/天。在部署的第一部分（从
10月中旬至11月中旬），一维模型的结果表明，
表面热通量和潮汐搅动之间的平衡是
对锋面位置的主要控制：由于热量损失到大气中，
全深度混合能够在逐渐加深的水中发生。在
部署后半期（11月中旬至12月初），
仅由热通量和潮汐搅动控制，
存在，但在观察中仍然存在一个前沿。我们分析水文
滑翔机收集的观测数据，
不同水团之间的边界，特别是
冷，盐水，南极起源水的存在，在更深的部分，
的部分。我们联合收割机结合这些结果提出，前面是一个混合
锋面：在夏季由热通量之间的局部平衡控制，
混合，在冬季作为水团之间的边界存在
从不同的源区平流到北海西北部。的
滑翔机的观测捕捉到了锋面转变的时期
从夏季到冬季的变化其他陆架海区的锋，
海洋的影响可能表现出类似的行为，
和地点每年都在变化。这些结果有一定的影响
陆架海的温盐环流。
Abstract. Tides and tidal mixing fronts are of fundamental importance to
understanding shelf sea dynamics and ecosystems. Ocean gliders enable the
observation of fronts and tide-dominated flows at high resolution. We use
dive-average currents from a 2-month (12 October–2 December 2013) glider
deployment along a zonal hydrographic section in the north-western North Sea
to accurately determine M2 and S2 tidal velocities. The results of
the glider-based method agree well with tidal velocities measured by current
meters and with velocities extracted from the TPXO tide model. The method
enhances the utility of gliders as an ocean-observing platform, particularly
in regions where tide models are known to be limited. We then use the
glider-derived tidal velocities to investigate tidal controls on the location
of a front repeatedly observed by the glider. The front moves offshore at a
rate of 0.51 km day −1 . During the first part of the deployment (from
mid-October until mid-November), results of a one-dimensional model suggest
that the balance between surface heat fluxes and tidal stirring is the
primary control on frontal location: as heat is lost to the atmosphere,
full-depth mixing is able to occur in progressively deeper water. In the
latter half of the deployment (mid-November to early December), a front
controlled solely by heat fluxes and tidal stirring is not predicted to
exist, yet a front persists in the observations. We analyse hydrographic
observations collected by the glider to attribute the persistence of the
front to the boundary between different water masses, in particular to
the presence of cold, saline, Atlantic-origin water in the deeper portion of
the section. We combine these results to propose that the front is a hybrid
front: one controlled in summer by the local balance between heat fluxes and
mixing and which in winter exists as the boundary between water masses
advected to the north-western North Sea from diverse source regions. The
glider observations capture the period when the front makes the transition
from its summertime to wintertime state. Fronts in other shelf sea regions with
oceanic influence may exhibit similar behaviour, with controlling processes
and locations changing over an annual cycle. These results have implications
for the thermohaline circulation of shelf seas.
影响因子：
--
作者：
F. Verspecht;T. Rippeth;M. J. Howarth;A. Souza;J. Simpson;H. Burchard
通讯作者：
F. Verspecht;T. Rippeth;M. J. Howarth;A. Souza;J. Simpson;H. Burchard