气候变化领域集成服务门户(CCPortal): Mechanisms of Exchange Flow in an Estuary With a Narrow, Deep Channel and Wide, Shallow Shoals

CCPortal

DOI	10.1029/2020JC016092
	Mechanisms of Exchange Flow in an Estuary With a Narrow, Deep Channel and Wide, Shallow Shoals
	Geyer W.R.; Ralston D.K.; Chen J.-L.
发表日期	2020
ISSN	21699275
卷号	125 期号:12
英文摘要	Delaware Bay is a large estuary with a deep, relatively narrow channel and wide, shallow banks, providing a clear example of a “channel-shoal” estuary. This numerical modeling study addresses the exchange flow in this channel-shoal estuary, specifically to examine how the lateral geometry affects the strength and mechanisms of exchange flow. We find that the exchange flow is exclusively confined to the channel region during spring tides, when stratification is weak, and it broadens laterally over the shoals during the more stratified neap tides but still occupies a small fraction of the total width of the estuary. Exchange flow is relatively weak during spring tides, resulting from oscillatory shear dispersion in the channel augmented by weak Eulerian exchange flow. During neap tides, stratification and shear increase markedly, resulting in a strong Eulerian residual shear flow driven mainly by the along-estuary density gradient, with a net exchange flow roughly 5 times that of the spring tide. During both spring and neap tides, lateral salinity gradients generated by differential advection at the edge of the channel drive a tidally oscillating cross-channel flow, which strongly influences the stratification, along-estuary salt balance, and momentum balance. The lateral flow also causes the phase variation in salinity that results in oscillatory shear dispersion and is an advective momentum source contributing to the residual circulation. Whereas the shoals make a negligible direct contribution to the exchange flow, they have an indirect influence due to the salinity gradients between the channel and the shoal. © 2020. The Authors.
英文关键词	estuarine circulation; lateral circulation; tidal dispersion
语种	英语
来源期刊	Journal of Geophysical Research: Oceans
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/186555
作者单位	Department of Applied Ocean Physics and Engineering, Woods Hole Oceanographic Institution, Woods Hole, MA, United States; Department of Hydraulic and Ocean Engineering, National Cheng Kung University, Tainan, Taiwan
推荐引用方式 GB/T 7714	Geyer W.R.,Ralston D.K.,Chen J.-L.. Mechanisms of Exchange Flow in an Estuary With a Narrow, Deep Channel and Wide, Shallow Shoals[J],2020,125(12).
APA	Geyer W.R.,Ralston D.K.,&Chen J.-L..(2020).Mechanisms of Exchange Flow in an Estuary With a Narrow, Deep Channel and Wide, Shallow Shoals.Journal of Geophysical Research: Oceans,125(12).
MLA	Geyer W.R.,et al."Mechanisms of Exchange Flow in an Estuary With a Narrow, Deep Channel and Wide, Shallow Shoals".Journal of Geophysical Research: Oceans 125.12(2020).