Tidal Currents in Juan de Fuca Strait

1954 ◽  
Vol 11 (6) ◽  
pp. 799-815 ◽  
Author(s):  
R. H. Herlinveaux
Keyword(s):  
Surface Current ◽  
Geodetic Survey ◽  
Tidal Currents ◽  
Bottom Surface ◽  
Strait Of Georgia ◽  
Juan De Fuca ◽  
Northern Shore ◽  
The Difference ◽  
Flood Current ◽  
Juan De Fuca Strait

Three series of direct current observations taken in Juan de Fuca Strait in 1952 have been analysed. A linear relationship between the difference in sea level on the ocean coast and the Strait of Georgia and tidal currents has been shown. This relation holds from the surface to the lower depths. The current velocities in a cross-section can be predicted at any time. These sections show that the ocean water tends to intrude along the bottom on the flood, expanding upward and favouring the southern shore. The ebbing water is first noticed in the middle of the strait, then it expands down and across favouring the northern shore. The ebb current is stronger at the surface, and the flood current stronger near the bottom. Surface current predictions are shown to be comparable to the U.S. Coast and Geodetic Survey tidal predictions. From this it is reasonable to believe that the predicted tidal currents at the lower depths should also be valid.

Surface Tidal Currents in Juan de Fuca Strait

1954 ◽  
Vol 11 (1) ◽  
pp. 14-31 ◽  
Author(s):  
R. H. Herlinveaux
Keyword(s):  
Pacific Ocean ◽  
Sea Level ◽  
Surface Current ◽  
Linear Functions ◽  
Strait Of Georgia ◽  
The Pacific ◽  
Juan De Fuca ◽  
The Pacific Ocean ◽  
The Difference ◽  
Juan De Fuca Strait

Surface-current measurements were made at half-hour intervals throughout thirty-hour periods at three positions in Juan de Fuca Strait. These were repeated during spring and neap ranges of the tide in spring, summer and late autumn during 1952. The currents are linear functions of the difference of sea level between the Pacific Ocean and the Strait of Georgia. A rule is given for predicting the currents from data in the Tide Tables.

Offshore Characteristics in the Deep Waters of the Strait of Georgia as Indicated by Bathypelagic Fish

1954 ◽  
Vol 11 (5) ◽  
pp. 501-506
Author(s):  
W. E. Barraclough ◽  
M. Waldichuk
Keyword(s):  
Deep Water ◽  
Fraser River ◽  
Strait Of Georgia ◽  
Deep Waters ◽  
Juan De Fuca ◽  
Bottom Waters ◽  
Chemical Conditions ◽  
Physical And Chemical ◽  
Juan De Fuca Strait ◽  
Inflowing Water

An attempt is made from oceanographical observations to explain the occurrence of certain bathypelagic species of fish which have been captured in the bottom waters of the southern Strait of Georgia. It is noted that there is a considerable seaward surface Sow of water from the Fraser River. The water from intermediate depths over the continental shelf forms the inflowing deep water of Juan de Fuca Strait mixing with the Fraser River water in the turbulent channels of the San Juan Archipelago. This mixture forms the deep inflowing water of southern Strait of Georgia and the outflowing surface water of the Juan de Fuca Strait as shown by salinity distribution and current measurements. The net inward movement of deep water is suggested as an agent of transport or a directive factor for the occurrence of these fish in this region. Physical and chemical conditions of the deep water in the Strait of Georgia are shown to be only slightly different from those found in the intermediate offshore water. It is probable that a combination of factors provides conditions suitable for survival of these species in the deep water of the southern Strait of Georgia.

Late Pleistocene history and geomorphology, southwestern Vancouver Island, British Columbia

1979 ◽  
Vol 16 (9) ◽  
pp. 1645-1657 ◽  
Author(s):  
Neville F. Alley ◽  
Steven C. Chatwin
Keyword(s):  
British Columbia ◽  
Continental Shelf ◽  
Late Pleistocene ◽  
Vancouver Island ◽  
Glacial Lakes ◽  
Small Lakes ◽  
Strait Of Georgia ◽  
Coast Mountains ◽  
Juan De Fuca ◽  
Juan De Fuca Strait

The major Pleistocene deposits and landforms on southwestern Vancouver Island are the result of the Late Wisconsin (Fraser) Glaciation. Cordilleran glaciers formed in the Vancouver Island Mountains and in the Coast Mountains had advanced down Strait of Georgia to southeastern Vancouver Island after 19 000 years BP. The ice split into the Puget and Juan de Fuca lobes, the latter damming small lakes along the southwestern coastal slope of the island. During the maximum of the glaciation (Vashon Stade), southern Vancouver Island lay completely under the cover of an ice-sheet which flowed in a south-southwesterly direction across Juan de Fuca Strait, eventually terminating on the edge of the continental shelf. Deglaciation was by downwasting during which ice thinned into major valleys and the strait. Most upland areas were free of ice down to an elevation of 400 m by before 13 000 years BP. A possible glacier standstill and (or) resurgence occurred along Juan de Fuca Strait and in some interior upland valleys before deglaciation was complete. Glacial lakes occupied major valleys during later stages of deglaciation.

A Model Study of the Salish Sea Estuarine Circulation*

2011 ◽  
Vol 41 (6) ◽  
pp. 1125-1143 ◽  
Author(s):  
David A. Sutherland ◽  
Parker MacCready ◽  
Neil S. Banas ◽  
Lucy F. Smedstad
Keyword(s):  
Puget Sound ◽  
Exchange Flow ◽  
Salish Sea ◽  
Strait Of Georgia ◽  
Model Study ◽  
Juan De Fuca ◽  
Residence Time Distributions ◽  
The Difference ◽  
First Time ◽  
Volume Transports

Abstract A realistic hindcast simulation of the Salish Sea, which encompasses the estuarine systems of Puget Sound, the Strait of Juan de Fuca, and the Strait of Georgia, is described for the year 2006. The model shows moderate skill when compared against hydrographic, velocity, and sea surface height observations over tidal and subtidal time scales. Analysis of the velocity and salinity fields allows the structure and variability of the exchange flow to be estimated for the first time from the shelf into the farthest reaches of Puget Sound. This study utilizes the total exchange flow formalism that calculates volume transports and salt fluxes in an isohaline framework, which is then compared to previous estimates of exchange flow in the region. From this analysis, residence time distributions are estimated for Puget Sound and its major basins and are found to be markedly shorter than previous estimates. The difference arises from the ability of the model and the isohaline method for flux calculations to more accurately estimate the exchange flow. In addition, evidence is found to support the previously observed spring–neap modulation of stratification at the Admiralty Inlet sill. However, the exchange flow calculated increases at spring tides, exactly opposite to the conclusion reached from an Eulerian average of observations.

Clustering coupled biochemical-physical model results formalizes regional provinces in a coastal region

2021 ◽  
Author(s):  
Susan Allen ◽  
Tereza Jarnikova ◽  
Elise Olson ◽  
Debby Ianson
Keyword(s):  
Physical Model ◽  
Three Dimensional ◽  
Coastal Region ◽  
Sparse Sampling ◽  
Strait Of Georgia ◽  
Northeast Pacific ◽  
Juan De Fuca ◽  
Main Basin ◽  
Physical Variables ◽  
Juan De Fuca Strait

<p>Coastal regions by their very nature are dynamically diverse.  Within one geographical region there are often multiple areas dominated by substantially different dynamics that shape not only the physical characteristics but also the ecosystem.  The Salish Sea, in the northeast Pacific, is an excellent example with strongly tidally mixed regions, freshwater-dominated regions, and regions directly influenced by the open ocean.  These regions are generally well known and multiple disciplines refer to them with various boundaries and under various names.  Here we use unsupervised clustering on numerical model results to formalize these regional provinces.  The model is SalishSeaCast,  a three-dimensional real-time coupled bio-chem-physical model based on the NEMO framework.  We find that the regions clustered on ecosystem variables (phytoplankton biomass) spatially coincide with those clustered on physical variables, particularly the stratification as diagnosed by the halocline depth.  The clusters are robust across years with interannual variability manifesting mostly in changes in the size of the clusters.  As the clusters are dynamically distinct, they provide a natural framework on which to evaluate the model against observations.  We find that the model accurately simulates each of the major clusters.  The spatial and temporal resolution of the model can then characterize these different clusters more systematically than the observations, revealing biases associated with sparse sampling in the observations. Two examples will be given, one addressing a long-standing issue of the productivity gradient in the stratified main basin, the Strait of Georgia, and another concerning the seasonal cycle of productivity in the ocean-influenced Juan de Fuca Strait.</p>

Some Oceanographic Features of Juan de Fuca Strait

1961 ◽  
Vol 18 (6) ◽  
pp. 1027-1071 ◽  
Author(s):  
R. H. Herlinveaux ◽  
J. P. Tully
Keyword(s):  
Fresh Water ◽  
Brackish Water ◽  
San Juan ◽  
Ocean Water ◽  
Lower Zone ◽  
Strait Of Georgia ◽  
Deep Waters ◽  
Juan De Fuca ◽  
Juan De Fuca Strait ◽  
Flood Flow

The distribution and structure of dissolved oxygen, salinity, temperature and density, and their seasonal and tidal variations are summarized, and related to the tidal and estuarine mechanisms.Juan de Fuca Strait is a complex, deep, positive estuary. It is divided into inner and outer parts by a sill extending southward across the channel from Victoria, B.C. The Inner Strait is separated from the Strait of Georgia by the San Juan Archipelago. The water structure in the Strait of Georgia is highly stratified due to the shallow brackish upper zone maintained by the Fraser River discharge. This brackish water tends persistently seaward due to the estuarine mechanism. In the passages through the San Juan Archipelago the shallow and deep waters are mixed to near homogeneity by the turbulent tidal flows. In the Inner Strait the stratification is small. Part of this mixed water is fed back into the lower zone of the Strait of Georgia, and part escapes seaward in the upper zone of the outer part of Juan de Fuca Strait, where it overruns the intruding ocean water, creating a new stratification. The ebb flow is stronger than the flood in this upper zone, and the halocline is deepest on the northern side of the strait.The flood flow, augmented by the deep inflow required by the estuarine mechanism, is strongest in the lower zone. Here the ocean waters advance over the sill during the flood flow, but do not retreat during the ebb flow, which is relatively weak. These ocean waters are incorporated with the mixed waters in the Inner Strait. This mechanism is a tidal pump.The concentration of fresh water in the upper zone of Juan de Fuca Strait varies from 2 to 6% during the year. The amount (depth of fresh water when separated from the ocean water in the system) varies from 1 to 7 m. In this and all other properties there is a gradient from the Strait of Georgia into the Inner Strait. In the Outer Strait there are cross-channel gradients, but none longitudinally.Throughout the system the density structure is salinity dominated. During the summer the thermocline coincides with the halocline. In winter the waters are isothermal, or the upper waters become slightly colder than the deep waters. Then the stability depends on the salinity structure alone.The salinity is a linear function of temperature within 0.1 °C, except at the surface in summer. The slope of the relation varies with time (season) and location. The relation shows that the waters throughout the system are mixtures of ocean water and brackish water from the Strait of Georgia, and tributary inlets.

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