Observations and modeling of tidally generated high-frequency velocity fluctuations downstream of a channel constriction

IF 4.1 3区地球科学 Q2 METEOROLOGY & ATMOSPHERIC SCIENCES

Ocean Science Pub Date : 2023-11-29 DOI:10.5194/os-19-1633-2023

Håvard Espenes, P. Isachsen, O. Nøst

引用次数: 0

Abstract

Abstract. We investigate data from an acoustic Doppler current profiler deployed in a constricted ocean channel showing a tidally dominated flow with intermittent velocity extrema during outflow from the constriction but not during inflow. A 2D numerical ocean model forced by tides is used to examine the spatial flow structure and underlying dynamical processes. We find that flow-separation eddies generated near the tightest constriction point form a dipole pair which propagates downstream and drives the observed intermittent flow variability. The eddies, which are generated by an along-channel adverse pressure gradient, spin up for some time near the constriction until they develop local low pressures in their centers that are strong enough to modify the background along-channel pressure gradient significantly. When the dipole has propagated some distance away from the constriction, the conditions for flow separation are recovered, and new eddies are formed.

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河道收缩下游潮汐产生的高频速度波动观测与建模

摘要我们研究了部署在一个收缩洋道中的声学多普勒海流剖面仪的数据，该数据显示潮汐主导的海流在从收缩洋道流出时具有间歇性极值速度，而在流入时则没有。我们利用潮汐作用下的二维数值海洋模型来研究空间流动结构和潜在的动力学过程。我们发现，在最紧收缩点附近产生的分流漩涡形成了一个偶极对，并向下游传播，推动了观测到的间歇性流动变化。由沿通道不利压力梯度产生的漩涡会在收缩点附近旋转一段时间，直到在其中心形成足以显著改变沿通道背景压力梯度的局部低压。当偶极子传播到离收缩处一段距离后，水流分离的条件恢复，新的漩涡形成。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Ocean Science 地学-海洋学

CiteScore

5.90

自引率

6.20%

发文量

审稿时长

6-12 weeks

期刊介绍： Ocean Science (OS) is a not-for-profit international open-access scientific journal dedicated to the publication and discussion of research articles, short communications, and review papers on all aspects of ocean science: experimental, theoretical, and laboratory. The primary objective is to publish a very high-quality scientific journal with free Internet-based access for researchers and other interested people throughout the world. Electronic submission of articles is used to keep publication costs to a minimum. The costs will be covered by a moderate per-page charge paid by the authors. The peer-review process also makes use of the Internet. It includes an 8-week online discussion period with the original submitted manuscript and all comments. If accepted, the final revised paper will be published online. Ocean Science covers the following fields: ocean physics (i.e. ocean structure, circulation, tides, and internal waves); ocean chemistry; biological oceanography; air–sea interactions; ocean models – physical, chemical, biological, and biochemical; coastal and shelf edge processes; paleooceanography.