气候变化领域集成服务门户(CCPortal): A Role for Gravity Currents in Cross-Sill Estuarine Exchange and Subsurface Inflow to the Southern Strait of Georgia

CCPortal

DOI	10.1029/2019JC015374
	A Role for Gravity Currents in Cross-Sill Estuarine Exchange and Subsurface Inflow to the Southern Strait of Georgia
	Thomson R.E.; Kulikov E.A.; Spear D.J.; Johannessen S.C.; Peter Wills W.
发表日期	2020
ISSN	21699275
卷号	125 期号:4
英文摘要	Multiyear current meter records from five sites are used to examine subsurface renewal processes in the southern Strait of Georgia. The lower layer inflow of dense oceanic-derived water over the ~100-m deep sill in Boundary Pass near the entrance to the strait reaches peak velocities during spring tides and rarely reverses direction. Corresponding changes in water density over the sill are inversely correlated with inflow velocity and, it is assumed, with temporal (t) variations in bottom layer thickness, h(t), arising from the fortnightly variations in tidal-mixing. The dense bottom water crossing the sill transforms into a gravity current whose velocity is dependent on both h and sill depth, H. Gravity flow velocities, which peak at h(t)/H ~ 0.3 and weaken for h → 0 (neap tides) and h → H (spring tides), modulate the cross-sill exchange with the strait. The density anomaly, Δρ, of the gravity flow determines its terminal depth and along-strait extent. Lower-density gravity flows generated during spring tides separate from the sloping bottom of the southern strait, but the higher-density flows formed during neap tides can penetrate over 100 km northward to the deep central basin. The most extensive bottom intrusions occur monthly near neap tides in summer, when the underlying estuarine circulation delivers dense upwelled water from the coast to the sill. These deep inflows are accompanied by strong middepth outflow. There are typically three to five monthly replacement episodes each summer, but fewer during strong El Niño years due to reduced coastal upwelling. ©2020. Her Majesty the Queen in Right of Canada Reproduced with the permission of the Minister of Fisheries and Oceans.
英文关键词	bottom-water renewal; coastal upwelling; estuarine circulation; gravity currents; Strait of Georgia; tidal mixing
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/186913
作者单位	Institute of Ocean Sciences, Fisheries and Oceans Canada, Sidney, BC, Canada; Shirshov Institute of Oceanology, Russian Academy of Sciences, Moscow, Russian Federation
推荐引用方式 GB/T 7714	Thomson R.E.,Kulikov E.A.,Spear D.J.,et al. A Role for Gravity Currents in Cross-Sill Estuarine Exchange and Subsurface Inflow to the Southern Strait of Georgia[J],2020,125(4).
APA	Thomson R.E.,Kulikov E.A.,Spear D.J.,Johannessen S.C.,&Peter Wills W..(2020).A Role for Gravity Currents in Cross-Sill Estuarine Exchange and Subsurface Inflow to the Southern Strait of Georgia.Journal of Geophysical Research: Oceans,125(4).
MLA	Thomson R.E.,et al."A Role for Gravity Currents in Cross-Sill Estuarine Exchange and Subsurface Inflow to the Southern Strait of Georgia".Journal of Geophysical Research: Oceans 125.4(2020).