Wave-Driven Inner-Shelf Motions on the Oregon Coast*
Wave-Driven Inner-Shelf Motions on the Oregon Coast*
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俄勒冈海岸波浪驱动的内陆架运动*
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
J. Barth
中科院分区：
文献类型：
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作者：
A. Kirincich;S. Lentz;J. Barth
S. Lentz等人最近的研究表明，由于与哈塞曼波应力（Stokes - Coriolis力）相关的波浪驱动回流，大陆架内部的海上运输。利用俄勒冈州中部海岸的观测资料，对该分析进行了扩展，以确定存在的波浪驱动回流，并量化由未解决的波浪驱动环流引起的风驱动跨大陆架交换的潜在偏差。利用声学多普勒电流剖面仪（ADCP）在水深为13 ~ 15 m的6个站点进行测量，观测到的平均深度和跨大陆架速度通常与建议回流的理论估计相关。在最小风强迫时期，跨大陆架速度剖面垂直剪切，在水柱测量部分的顶部附近有较强的速度，并且随着显著波高的增加而增加，与哈塞曼波应力引起的环流一致。然而，速度震级和垂直剪切比线性波理论预测的更强，更类似于S. Lentz等人描述的分层“夏季”速度剖面。此外，还发现了波浪驱动回流的大量时空变异性，这可能是由于风和波条件的变化以及当地的水深变异性。尽管发现了波浪驱动环流，但从观测到的跨大陆架速度中减去返回流的估计，对夏季俄勒冈海岸这些水域的沿大陆架风强迫导致的跨大陆架交换的估计没有显著影响。
Recent work by S. Lentz et al. documents offshore transport in the inner shelf due to a wave-driven return flow associated with the Hasselmann wave stress (the Stokes‐Coriolis force). This analysis is extended using observations from the central Oregon coast to identify the wave-driven return flow present and quantify the potential bias of wind-driven across-shelf exchange by unresolved wave-driven circulation. Using acoustic Doppler current profiler (ADCP) measurements at six stations, each in water depths of 13‐15 m, observed depth-averaged, across-shelf velocities were generally correlated with theoretical estimates of the proposed return flow. During times of minimal wind forcing, across-shelf velocity profiles were vertically sheared, with strongervelocitiesnearthetop of themeasuredportionofthe watercolumn,andincreasedin magnitudewith increasing significant wave height, consistentwith circulation due to the Hasselmann wave stress. Yet velocity magnitudes and vertical shears were stronger than that predicted by linear wave theory, and more similar to the stratified ‘‘summer’’ velocity profiles described by S. Lentz et al. Additionally, substantial temporal and spatial variability of the wave-driven return flow was found, potentially due to changing wind and wave conditions as well as local bathymetric variability. Despite the wave-driven circulation found, subtracting estimates of the return flow from the observed across-shelf velocity had no significant effect on estimates of the across-shelf exchange dueto along-shelfwind forcing at these waterdepths along the Oregoncoast during summer.