PNWTOX simulations

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PNWTOX numerical model - physics

physical model - (Giddings et al. 2014, Sutherland et al. 2011, and the UW Coastal Modeling Group)

PNWTOX model domain

The left panel shows the entire model domain with tick marks every 2 grid cells. The highest resolution is 1.5 km near the coastline extending out to 4.5 km offshore and 2 km within the Salish Sea leading to a horizontal grid of 174 x 381 grid cells. The right panel shows a cross sections of the vertical grid at 47N. There are 40 vertical levels with stretching parameters chosen to increase resolution both near the surface and in the bottom boundary layer.

forcing

Modeling of the Salish Sea (MoSSea) Modeling framework developed by MacCready Coastal Modeling Group (more info: PM homepage and University of Washington Coastal Modeling Group, Sutherland et al. 2011, MacCready et al. 2009, Liu et al. 2009)

ROMS hindcast simulations (Shchepetkin and McWilliams 2003, 2005) with realistic boundary and forcing conditions:

• high-resolution bathymetry from (Smith and Sandwell 1997; Haugerud 2000; Finlayson 2005)
• NCOM global boundary conditions, nudging, and initial conditions (Barron et al. 2006)
• MM5 atmospheric model winds, atmospheric pressure, heat fluxes, rainfall, and relative humidity (Mass et al. 2003)
• tidal free surface and velocity boundary conditions using 8 tidal constituents from the TPXO7.1 tidal model (Eggbert and Erofeeva, 2002)
• 16 river point sources (USGS and Environment Canada)
• biogeochemical/physical MoSSea model coupling is also included in this model by N. Banas, K. Davis, and S. Siedlecki

model set-up

a vast number of choices can be made when setting up a model configuration, a few of the important ones are listed here:

• boundary nudging has an incoming time scale of 0.75d and and outgoing timescale of 360d at the boundary and is increased towards infinity over 6 grid cells
• k- ε version of GLS turbulence closure
• horizontal diffusivity and viscosity set to 2.0 m²s^-1
• quadratic bottom friction (C_d = 0.003) and no-slip
• bathymetry min = 4 m, no wetting/drying yet
• bathymetry smoothed using a volume preserving scheme that best preserves the original bathymetry (Sikiric 2011) resulting in: max Beckmann & Haidvogel # (rx₀) ~0.15, max Haney # (rx₁) ~9

UW Coastal Modeling Group

This work was supported by grants from the Coastal Ocean Program of the National Oceanic and Atmospheric Administration (NOAA) (NA09NOS4780180) and the National Science Foundation (NSF) (OCE0942675) as part of the PNWTOX project. The statements, findings, conclusions, and recommendations are those of the participants/authors and do not reflect the views of NSF, NOAA or the Department of Commerce.