Variations in the Onset of Bottom-Water Intrusions over the Entrance Sill of a Fjord

Cannon, G. A.; Holbrook, James R.; Pashinski, David J.

doi:10.2307/1351430

Cited by 49 publications

(24 citation statements)

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“…To examine the influence of upwelling, an Upwelling Index (UI ) available from the Pacific Fisheries Environmental Laboratory for the same longitude and latitude as the wind data used by Cannon et al (1990) is used. This index is lagged by 7.25 days (consistent with the temporal relationship they determined between offshore wind observations and subsequent effects at Admiralty Inlet) and then compared with the dissolved oxygen time series from Admiralty Inlet in Fig.…”

Section: Intrusion Analysis and Prediction Indices For Admiralty Inletmentioning

confidence: 99%

“…They also found increases in bottom salinity near Admiralty Sill following the cessation of coastal storms with downwelling conditions. The bottom salinity at Admiralty Inlet is found to lag strong southerly (Cannon et al 1990). …”

Section: Introductionmentioning

confidence: 96%

“…An increase in this density difference would increase the strength a twolayer exchange flow in the Strait of Juan de Fuca (Helfrich 1995). Cannon et al (1990) note that coastal upwelling and downwelling, in particular, may be important factors for the availability of near-bed dense water on the seaward side of Admiralty Inlet as well. Cannon et al (1990) observe that coastal storms in the winter, which cause downwelling along the coast, may suppress high-salinity water intrusions by causing flow reversals along the length of the Strait of Juan de Fuca, reducing the density of the bottom water seaward of Admiralty Sill.…”

Section: Introductionmentioning

confidence: 99%

“…Cannon et al (1990) note that coastal upwelling and downwelling, in particular, may be important factors for the availability of near-bed dense water on the seaward side of Admiralty Inlet as well. Cannon et al (1990) observe that coastal storms in the winter, which cause downwelling along the coast, may suppress high-salinity water intrusions by causing flow reversals along the length of the Strait of Juan de Fuca, reducing the density of the bottom water seaward of Admiralty Sill. They calculate a strong inverse correlation between bottom salinity near Admiralty Sill and coastal sea level height.…”

Section: Introductionmentioning

confidence: 99%

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Predicting Deep Water Intrusions to Puget Sound, WA (USA), and the Seasonal Modulation of Dissolved Oxygen

Deppe

Thomson

Polagye

et al. 2017

Estuaries and Coasts

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Observations and predictions regarding oceanic intrusions at the entrance to Puget Sound, WA (USA), are presented. Four years of seabed observations at Admiralty Inlet show episodic periods high salinity, coincident with landward residual currents near the seabed. The observed residual currents are consistent with an estuarine exchange flow during minimal tidal mixing, coincident with neap currents and maximum diurnal inequalities. These subtidal intrusions can carry dense water into Puget Sound and, thereby, renew the bottom water that is trapped landward of the sill. The oxygen concentration levels of these intrusions are often low, though not hypoxic, and may influence Communicated by Carl T. Friedrichs R. Walter Deppe does not currently work at the University of Washington. The work for this project was conducted while he was a research assistant at the University of Washington. the oxygen levels in Puget Sound. The water mass properties of these intrusions are influenced strongly by regional dynamics, because the entrance to Puget Sound is connected to the open ocean via the Strait of Juan de Fuca. Coastal upwelling and discharge from the Fraser River discharge control the exchange flow in the Strait of Juan de Fuca and thus control the availability of dense water at the entrance to Puget Sound. The net effect of the tidal and regional dynamics is for intrusions with low oxygen levels to prevail in the late summer months. To predict intrusions in future years, an empirical method is developed and validated for daily application. The prediction method is based on publicly available operational data products and does not require in situ observations. In verification, 98% of intrusion events with dissolved oxygen less than 4.0 mg/L are successfully identified in a hindcast prediction for the 4-year observational record.

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Section: Intrusion Analysis and Prediction Indices For Admiralty Inletmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Predicting Deep Water Intrusions to Puget Sound, WA (USA), and the Seasonal Modulation of Dissolved Oxygen

Deppe

Thomson

Polagye

et al. 2017

Estuaries and Coasts

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show abstract

“…No substantial reversals in this pattern occurred during the period of data collection at Cocodrie and thus, mode 2 appears to be gravitationally-driven estuarine exchange flow, and this exchange flow responded strongly to variations in the longitudinal salinity gradient. The dependence of gravitational circulation on the longitudinal density gradient has been described analytically by [2], and numerous observational studies have documented this response, where enhanced density gradients drove stronger gravitational circulation [42] or even reversed it in the case of inverse estuaries where estuarine salinities exceeded those in shelf waters [43][44][45][46][47].…”

Section: Vertical Variation In Subtidal Velocity Dtructure At Cocodriementioning

confidence: 99%

Drivers of Barotropic and Baroclinic Exchange through an Estuarine Navigation Channel in the Mississippi River Delta Plain

Snedden

2016

Water

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Estuarine navigation channels have long been recognized as conduits for saltwater intrusion into coastal wetlands. Salt flux decomposition and time series measurements of velocity and salinity were used to examine salt flux components and drivers of baroclinic and barotropic exchange in the Houma Navigation Channel, an estuarine channel located in the Mississippi River delta plain that receives substantial freshwater inputs from the Mississippi-Atchafalaya River system at its inland extent. Two modes of vertical current structure were identified from the time series data. The first mode, accounting for 90% of the total flow field variability, strongly resembled a barotropic current structure and was coherent with alongshelf wind stress over the coastal Gulf of Mexico. The second mode was indicative of gravitational circulation and was linked to variability in tidal stirring and the horizontal salinity gradient along the channel's length. Tidal oscillatory salt flux was more important than gravitational circulation in transporting salt upestuary, except over equatorial phases of the fortnightly tidal cycle during times when river inflows were minimal. During all tidal cycles sampled, the advective flux, driven by a combination of freshwater discharge and wind-driven changes in storage, was the dominant transport term, and net flux of salt was always out of the estuary. These findings indicate that although human-made channels can effectively facilitate inland intrusion of saline water, this intrusion can be minimized or even reversed when they are subject to significant freshwater inputs.

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Methane Plume Emissions Associated with Puget Sound Faults in the Cascadia Forearc

Johnson

Merle

Bjorklund

et al. 2021

Preprint

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This research requires a scientific staff with a broad range of disciplinary backgrounds, a strong technical support staff, and a research approach that integrates field, laboratory, and analytical efforts. The staff is organized into six research groups sharing a disciplinary or technical focus (fig. 1). The interdisciplinary projects constituting most of PMEL's activity --_ surface temperature distributions in the equatorial ocean. Heat transport by major western boundary currents, the Gulf Stream and Kuroshio in the Northern Hemisphere, are also postulated to have an important impact on world cli mate. Studies during 1982 focused on the Florida Current as part of the Subtropical Atlantic Climate Study (STACS) and the Kuroshi0 in the vicinity of the Emperor Seamounts. These two studies will provide insight into the fluctuations of two of the world's major currents. PMEL is also conducting two unique marine-chemistry re search activities for NOAA under the National Climate Program. These activities relate to the ocean's behavior as a sink for atmospheric carbon dioxide, which has been steadi ly increasing over the past century. One project measures the flux of human-made fluorocarbons into the ocean in order to trace gaseous diffusion across the ocean-atmosphere boundary. The other project is examining the role of biolo gically produced, particulate calcium carbonate as an ab sorber of carbon dioxide at high latitudes. Together these studies will help determine the potential of the oceans for absorbing carbon dioxide. OCEAN SERVICES RESEARCH AND DEVELOPMENTThe goal of the PMEL program in ocean services is to im prove NOAA's capabilities for providing information, fore casts, and warnings of possible environmental hazards to people in the offshore and coastal areas of the United States. PMEL scientists, in conjunction with personnel from NOAA operational elements, have identified priority areas where directed research can provide substantial improvement in marine forecasting and prediction. Research under way in 1982 was aimed at predicting the movement of the Bering Sea ice edge, predicting coastal wave conditions at harbor entrances, and improving tsunami forecasts and warnings in the Pacific Basin. The U.

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Variations in the Onset of Bottom-Water Intrusions over the Entrance Sill of a Fjord

Cited by 49 publications

References 9 publications

Predicting Deep Water Intrusions to Puget Sound, WA (USA), and the Seasonal Modulation of Dissolved Oxygen

Predicting Deep Water Intrusions to Puget Sound, WA (USA), and the Seasonal Modulation of Dissolved Oxygen

Drivers of Barotropic and Baroclinic Exchange through an Estuarine Navigation Channel in the Mississippi River Delta Plain

Methane Plume Emissions Associated with Puget Sound Faults in the Cascadia Forearc

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