Subtidal circulation in a deep‐silled fjord: Douglas Channel, British Columbia
Subtidal circulation in a deep‐silled fjord: Douglas Channel, British Columbia
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深槽峡湾的潮下环流：不列颠哥伦比亚省道格拉斯海峡
DOI：
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
S. Dosso
中科院分区：
文献类型：
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作者：
D. Wan;C. Hannah;M. Foreman;S. Dosso
道格拉斯海峡是加拿大不列颠哥伦比亚省西海岸的一个深水峡湾，是峡湾系统中的主要水道，连接基蒂马特镇和夏洛特女王湾和赫卡特海峡。一个200米深的岩床将道格拉斯海峡分为外海盆和内海盆。本研究根据2013-2015年部署的三个系泊系统收集的数据，研究了道格拉斯海峡的低频（从季节到气象波段）环流。深流主要由每年的更新，发生在5月/6月至9月初。厚100米的致密底层以0.1-0.2 m s−1的速度级联通过系统，这与重力流一致。河口流占主导地位的环流以上的窗台深度，和观察到的向陆地的净体积通量表明，它是必要的，包括整个复杂的通道网络，以充分了解河口环流系统。风强迫对潮下带环流的影响不仅表现在表层，而且表现在中层。顺槽风主导表层流速波动，海平面对风的响应在100-120 m处产生逆风向的流速信号。总的来说，在季节和气象带的环流是河口流，直接风驱动的流，和正压和斜压响应的风应力引起的表面压力梯度的变化的混合。
Douglas Channel, a deep fjord on the west coast of British Columbia, Canada, is the main waterway in the fjord system that connects the town of Kitimat to Queen Charlotte Sound and Hecate Strait. A 200 m depth sill divides Douglas Channel into an outer and an inner basin. This study examines the low-frequency (from seasonal to meteorological bands) circulation in Douglas Channel from data collected at three moorings deployed during 2013–2015. The deep flows are dominated by a yearly renewal that takes place from May/June to early September. A dense bottom layer with a thickness of 100 m that cascades through the system at the speed of 0.1–0.2 m s−1, which is consistent with gravity currents. Estuarine flow dominates the circulation above the sill depth, and the observed landward net volume flux suggests that it is necessary to include the entire complex channel network to fully understand the estuarine circulation in the system. The influence of the wind forcing on the subtidal circulation is not only at the surface, but also at middepth. The along-channel wind dominates the surface current velocity fluctuations and the sea level response to the wind produces a velocity signal at 100–120 m in the counter-wind direction. Overall, the circulation in the seasonal and the meteorological bands is a mix of estuarine flow, direct wind-driven flow, and the barotropic and baroclinic responses to changes to the surface pressure gradient caused by the wind stress.