WAMSI Node 6.2 - Tidally generated internal waves on the Australian North West Shelf - ROMS model

Brief description

A numerical circulation model was developed to provide a comprehensive understanding and predictive capability of the tidal motions and tidally driven internal wave climatology on the North West Shelf of Western Australia from Inner shelf region to a water depth exceeding 5km. This will undertaken using the ROMS v3.1 (Haidvogel et al., 2000; Shchepetkin and McWilliams, 2005) model which is a hydrostatic, primitive equation, sigma coordinate ocean model.

Lineage

Statement: ROMS v3.1 (Haidvogel et al., 2000; Shchepetkin and McWilliams, 2005) is a hydrostatic, primitive equation, sigma coordinate ocean model that solves the Reynolds averaged form of the Navier-Stokes equations on a Arakawa ''C'' grid. ROMS is run on a domain of approximately 800 km by 500 km with the horizontal grid resolution set to a nominal 2.2 km grid resolution. The model minimum depth was set to 20 m and the number of vertical sigma layers was set to 70, with increased resolution in the near seabed layers. The bottom stress was computed using a quadratic stress with bottom drag coefficient of 0.0025. The model domain consists of three open boundaries located on the study area's northern, southern, and western extents (see thumbnail). Representation of the internal forcing was accomplished through the one way coupling of ROMS to the coarse scale data assimilating ocean circulation model Bluelink ReANalysis (BRAN) version 2.1, see Oke et al. (2008), by maintaining a daily varying boundary condition for temperature and salinity at all open boundaries. Initial conditions for the temperature and salinity fields were also obtained from BRAN and thus we have realistic spatially varying fields over the domain. The initial velocity field was set to zero for all components. Tidal forcing was applied using the Ohio State University TPXO.7.1 tide model, carrying the four dominant diurnal and semi-diurnal tidal constituents at the boundaries. Wind forcing was applied using daily averaged blended vector sea surface winds (at 10-m above sea level) observations, on a global 0.25-degree grid sourced from the National Climatic Data Center (NCDC). Daily averaged thermodynamic forcing data was obtained from the National Oceanic and Atmospheric Administration NCEP/NCAR reanalysis data set.