The coupled estuarine‐shelf response of a river‐dominated system during the transition from low to high discharge
The coupled estuarine‐shelf response of a river‐dominated system during the transition from low to high discharge
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河流主导系统从低流量向高流量转变期间的河口-陆架耦合响应
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
R. Collini
中科院分区：
文献类型：
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作者：
B. Dzwonkowski;Kyeong Park;R. Collini
当阿拉巴马州沿海地区从低水期过渡到洪水河流量条件时，机会主义观测捕捉到了河口与陆架的耦合相互作用。重点关注期为2011年2月18日至4月10日，在此期间，现场（水位、盐度和速度）和遥感（海洋颜色）数据的结合提供了有关主要河流排放事件之前、期间和之后河口和陆架环境的信息，捕获了排放羽流响应不断变化的强迫条件的结构演化的相对罕见的空间概要视图。泄洪事件使水文条件发生了重大变化，并迫使河口和陆架发生反应。由此产生的表面平流羽流被观察了大约两周，在此期间，观察到的陆架循环差异与排放羽流直接相关，并且在整个事件中有时发现具有反气旋循环的羽流隆起。羽流暴露在一系列调节表面结构的风力条件下：下降风拉长羽流结构，上升风反转并加宽羽流。由于羽流的浅而宽的特征，即使在风力非常低（<3.75 m s−1）和大流量（∼7000 m3 s−1）条件下，风力强迫的影响也是显而易见的。仅在少数系统中发现了反气旋隆起区域，并且阿拉巴马陆架上这一特征的出现对该区域河流排放的运输和命运具有重大影响。
Opportunistic observations captured the coupled estuarine-shelf interactions as the Alabama coastal region transitioned from a period of low to flood river discharge conditions. The period of focus was 18 February to 10 April 2011 during which time a combination of in situ (water level, salinity and velocity) and remote sensing (ocean color) data provided information on the estuarine and shelf environment prior to, during, and post a major river discharge event that captured a relatively rare spatially synoptic view of the structural evolution of a discharge plume in response to changing forcing conditions. The discharge event generated major changes in the hydrographic conditions and forcing responses within the estuary and on the shelf. The resulting surface advected plume was observed for approximately two weeks, during which time the observed differences in shelf circulation were directly linked to the discharge plume and a plume bulge with anticyclonic circulation was identified at times throughout the event. The plume was exposed to a range of wind conditions which modulated the surface structure: downwelling winds elongated the plume structure and upwelling winds reversed and widened the plume. The influence of wind forcing, even during very low wind (<3.75 m s−1) and large outflow (∼7000 m3 s−1) conditions, was apparent, as a result of the shallow and wide characteristics of the plume. Anticyclonic bulge regions have only been identified in a few systems and the occurrence of this feature on the Alabama shelf has significant implications on transport and fate of river discharge in this region.