Presentation Abstract

An improved version of a diagnostic hydrodynamic and biogeochemical model (nutrients, phytoplankton, carbon, dissolved oxygen, pH) of the Salish Sea has been developed with the ability to simulate characteristic circulation and water quality features. Notable improvements include expansion of the model domain beyond the Salish Sea, encompassing Vancouver Island and out to the continental shelf boundary. In this talk we present an overview of the model setup describing the model domain coverage, modeling framework, development of boundary conditions, and tidal, riverine, wastewater, and meteorological inputs. Ability of the model to reproduce known circulation features within the Salish Sea is highlighted. The existence of a strong circulation cell between Admiralty Inlet and Tacoma Narrows sills is discussed reflecting on the implications of reflux flow back into Central Puget Sound. Simulation of sediment diagenesis processes and coupling to the water column provides improved model performance that is responsive to land based and oceanic nutrient loads. This coupling is also credited with the improvements in simulation of hypoxia in selected sub-basins within the Salish Sea such as Hood Canal, Penn Cove, and East Sound. Using tidally averaged velocity profiles from the Salish Sea Model, we demonstrate that Hood Canal sub-basin, with a sill near the mouth, a deep channel configuration, and a freshwater source at its landward end, behaves like a classic-fjord. The dominant and notable feature is that circulation and exchange in the inner basin of Hood Canal occurs in the upper 40% of the water column while the lower 60% remains poorly mixed and relatively isolated from the exchange. This results in conditions well suited for the settling of organic matter and long residence times >230 days, and causes recurring hypoxia in the inner regions of Hood Canal in late fall.

Session Title

Understanding the Salish Sea Model and its Application for Puget Sound Recovery

Conference Track

SSE15: Data and Information Management

Conference Name

Salish Sea Ecosystem Conference (Seattle, WA : 2018)

Document Type

Event

SSEC Identifier

SSE15-198

Start Date

4-4-2018 1:30 PM

End Date

4-4-2018 1:45 PM

Type of Presentation

Oral

Contributing Repository

Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.

Geographic Coverage

Salish Sea (B.C. and Wash.)

Rights

This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.

Type

text

Language

English

Format

application/pdf

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Apr 4th, 1:30 PM Apr 4th, 1:45 PM

An overview of the Salish Sea model: existence of reflux mixing and recurring hypoxia

An improved version of a diagnostic hydrodynamic and biogeochemical model (nutrients, phytoplankton, carbon, dissolved oxygen, pH) of the Salish Sea has been developed with the ability to simulate characteristic circulation and water quality features. Notable improvements include expansion of the model domain beyond the Salish Sea, encompassing Vancouver Island and out to the continental shelf boundary. In this talk we present an overview of the model setup describing the model domain coverage, modeling framework, development of boundary conditions, and tidal, riverine, wastewater, and meteorological inputs. Ability of the model to reproduce known circulation features within the Salish Sea is highlighted. The existence of a strong circulation cell between Admiralty Inlet and Tacoma Narrows sills is discussed reflecting on the implications of reflux flow back into Central Puget Sound. Simulation of sediment diagenesis processes and coupling to the water column provides improved model performance that is responsive to land based and oceanic nutrient loads. This coupling is also credited with the improvements in simulation of hypoxia in selected sub-basins within the Salish Sea such as Hood Canal, Penn Cove, and East Sound. Using tidally averaged velocity profiles from the Salish Sea Model, we demonstrate that Hood Canal sub-basin, with a sill near the mouth, a deep channel configuration, and a freshwater source at its landward end, behaves like a classic-fjord. The dominant and notable feature is that circulation and exchange in the inner basin of Hood Canal occurs in the upper 40% of the water column while the lower 60% remains poorly mixed and relatively isolated from the exchange. This results in conditions well suited for the settling of organic matter and long residence times >230 days, and causes recurring hypoxia in the inner regions of Hood Canal in late fall.