Ebb-Tide Dynamics and Spreading of a Large River Plume*
Ebb-Tide Dynamics and Spreading of a Large River Plume*
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DOI：
10.1175/2009jpo4061.1
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发表时间：
2009-11
影响因子：
3.5
通讯作者：
R. McCabe;P. MacCready;B. Hickey
中科院分区：
文献类型：
--
作者：
R. McCabe;P. MacCready;B. Hickey
摘要研究了一个大型潮汐脉冲河流羽流近场区的动量平衡。作者集中在一个单一的落潮的哥伦比亚河羽流，使用区域海洋模拟系统（ROMS）配置后向流条件在华盛顿州和俄勒冈州的货架和哥伦比亚河口。在落潮期间，羽流内部流向平衡主要在平流、压力梯度和摩擦力之间。在这个区域中的流法向平衡简化为离心力、横流压力梯度和科里奥利项（即，在河流卷流膨胀调查中通常假设的“梯度风”平衡）。时间导数在羽流前沿和退潮过程中最为重要。风很小，对力量平衡的贡献很小。Midebb应力和垂直盐通量是最大的中羽深度，分层和垂直剪切也很高，与剪切诱导的混合。内部应力减缓了烟羽的扩散。
Abstract Momentum balances in the near-field region of a large, tidally pulsed river plume are examined. The authors concentrate on a single ebb tide of the Columbia River plume, using the Regional Ocean Modeling System (ROMS) configured to hindcast flow conditions on the Washington and Oregon shelves and in the Columbia River estuary. During ebb, plume-interior streamwise balances are largely between advection, pressure gradient, and frictional forces. Stream-normal balances in this region reduce to centrifugal, cross-stream pressure gradient, and Coriolis terms (i.e., the “gradient wind” balance commonly assumed in river plume bulge investigations). Temporal derivatives are most important at the plume front and as the ebb progresses. Winds were light and contributed little to the force balance. Midebb stress and vertical salt flux were largest at a midplume depth, where stratification and vertical shear were also high, consistent with shear-induced mixing. Internal stress slows the spreading plume consi...