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Modeling Puget Sound Circulation Mitsuhiro Kawase School of Oceanography PRISM Retreat, 2002.
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Modeling Puget Sound CirculationMitsuhiro KawaseSchool of OceanographyPRISM Retreat, 2002
National Ocean Partnership ProgramA Partnership for Modeling the Marine Environment of Puget Sound, WashingtonONR Award N000140210503Mitsuhiro Kawase, Allan Devol, Miles Logsdon and Mark Warner, School of OceanographyWilliam Winn, College of EducationUniversity of Washington, Seattle, WAFY 02 Funding: $390,924 Objectives: • Develop, maintain and operate a system of simulation models of Puget Sound’s circulation and ecosystem, a data management system for oceanographic data and model results, and an effective delivery interface for the model results and observational data for research, education and policy formulation. • Develop fundamental understanding of the Sound’s working, and address questions raised by the regional community concerning management of the Sound and its resources. Partners: • Department of Natural Resources, King County, Washington (R. Shuman, B. Nairn) • Department of Ecology, State of Washington (J. Newton) • Puget Sound Naval Shipyard (S. Swanson, R. Johnston) • Ocean Inquiry Project (F. Stahr, C. Sarason)
Puget Sound Circulation Model • Support from National Oceanographic Partnership Program (NOPP), FY 2002 - 2008 • In collaboration with King County DNR • Based on Princeton Ocean Model (POM) code • 360x540m resolution,14 vertical levels • Predicted variables: Velocity, temperature, salinity, turbulent kinetic energy, turbulent master length Model domain and bathymetry
Puget Sound Circulation Model (Cont’d) • Hindcasting Year 2000 (with Bruce Nairn, KC-DNR): • Accurate time-average exchange circulation in the Main Basin • Accurate time-average recirculation around Vashon Island (northward current 30cm/s in Colvos Passage) • Excessive transport into the deep Whidbey Basin (~20%) - dynamics of the Skagit Delta, Deception Pass transport?
Puget Sound Circulation ModelTasks FY 2002 • Complete coupling with the MM5 weather prediction model • Routine hindcasting of Puget Sound circulation • Dynamics of Carr Inlet • Generate Lagrangian trajectories for study of planktonic genetic diversity (diatoms, geoducks)
Variability at Seasonal/Interannual Time Scales • Historical data analysis • Simple model of Puget Sound circulation for quantitative sensitivity study
Schematic of exchange circulation in a fjord (cross-section) River Input (Fresh, Light) Outflow Tidal Mixing Sharp Pycnocline Main Basin Marine influence (Salty, Dense) Inflow/Reflux Entrance Sill
Terrestrial Influence = River Runoff • Maximum in Winter/Spring • Marine Influence = Coastal Upwelling • Maximum in Spring/Summer
“Light Phase” “Dense Phase” T/S Seasonal Cycle in Puget Sound Main Basin (1992)
A Box Model of Puget Sound CirculationAmanda Babson, M.S. Thesis • Twelve boxes to represent Puget Sound (six regions, upper and lower layer) • Predicts salinity in each box, advective fluxes between boxes and mixing between upper and lower boxes • Forced by river discharge and external salinity in deep Admiralty Inlet • Conservation of mass and salt, simple parameterization of momentum and vorticity balance, and stratification-dependent vertical mixing
Salinity in a Box Model of Puget Sound Circulation (Babson, 2002)
1 0 Volume Transport (x109 cubic meters per day) -1 Seasonal Transport in the Box Model (positive = out) Outflow at Surface Inflow at Depth Jan Apr Jul Oct
12 12 10 10 June 8 8 Dalco Passage Admiralty Inlet Sills Main Basin SJDF December Black line: Last contiguous density surface across Admiralty Inlet Potential Temperature 1999
1997: Year of no density intrusion Salinity and Potential Density in Central Puget Sound, 1990 - 1998(Blue: 100m Red: 200m)