Abstract:

This dataset contains fields generated using the Coupled-Ocean-Atmosphere-Wave-Sediment Transport (COAWST) model to investigate the effects of temperature gradients produced by the differing thermal properties of oil and water. COAWST consists of a coupled Regional Ocean Modeling System (ROMS) ocean model, Simulating Waves Nearshore (SWAN) wave model, and Weather Research and Forecasting (WRF) atmospheric model. The fields are saved every six hours from 2010-04-21 to 2010-05-04. The ocean model has a 2 km horizontal grid spanning 18.4°N - 39.95°N and 98°W - 76.4°W and 32 vertical levels, with finer grid near the surface to resolve the near-surface shear. Included components are the COASWT report file, WRF input file, the ROMS output files, the ROMS six-hour time average fields, the WRF output files, and significant wave height from SWAN. Variables are reported at intervals of six hours. Two full sets of model output are included, one containing the results with no consideration of the effect of oil cover on surface moisture flux effects (directory GB.BVW1-QFX0) and one containing the results incorporating those effects (directory GB.BVW1-QFX1).

Suggested Citation:

Zheng, Yangxing, Mark A. Bourassa, and Stephen Van Gorder. 2020. Coupled-Ocean-Atmosphere-Wave-Sediment Transport (COAWST) modeling of surface roughness and circulation changes owing to thermal gradients created by the presence of slick, 2010-04-21 to 2010-05-04. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/n7-c22e-ae76

Purpose:

To examine the effect of surface temperature gradient owing to the thermal property between oil and water on the surface oil transport in the Gulf of Mexico.

Data Parameters and Units:

Zonal and meridional ocean currents (m/s), temperature (degC), surface oil distribution (no unit), wave height (m), wave length (m), 10-meter zonal and meridional winds (m/s), surface sensible heat flux (W/m2), surface latent heat flux (W/m2), Aoil: surface oil coverage fraction (unites, values ranging 0 to 1). SSOT: surface oil tracer concentration (kg/m3) SWAN model output (significant wave height): time (Unix epoch format, seconds since 1970-01-01 [s]), longitude [decimal degrees E], latitude [decimal degrees N], significant wave height (hs, [m]). ROMS model output: key variables include latitude and longitude at eta, psi, u, v, and rho points [decimal degrees], bathymetry [m], land/water masks for rho, u, v, and psi points [0/1], time (ocean_time, VMS epochformat, seconds since 1858-11-17 00:00:00 [seconds]), free surface height (zeta, [m]), vertically-integrated zonal momentum (ubar, [m/s]), vertically-integrated meridional momentum (vbar, [m/s]), zonal momentum (u, [m/s]), meridional momentum (v, [m/s]), vertical momentum (w, [m/s]), S-coordinate vertical momentum (omega, [m/s]), potential temperature (temp, [degrees C]), salinity (salt), dye_01 ([kg/m^3]), turbulent kinetic energy (tke, [m^2/s^2]), surface air pressure (Pair, [mbar]), surface u wind (Uwind, [m/s]), surface v wind (Vwind, [m/s]), surface zonal wind (Uwind_eastward, [m/s]), surface meridional wind (Vwind_eastward, [m/s]), net surface heat flux (shflux, [W/m^2]), net surface salt flux (ssflux, [m/s]), net latent heat flux (latent, [W/m^2]), net surface sensible heat flux (sensible, [W/m^2]), net longwave radiation flux (lwrad, [W/m^2]), net bulk flux of freshwater (EminusP, [m/s]), evaporation rate (evaporation, [kg/m^2/s]), rain rate (rain, kg/m^2/s]), shortwave radiation flux, [W/m^2]), surface u momentum flux (sustr, [N/m^2]), surface v momentum flux (svstr, [N/m^2]), bottom u momentum flux (bvstr, [N/m^2]), bottom v momentum flux (bvstr, [N/m^2]), Stokes drift velocities {u, v, w, vertically-integrated u, vertically-integrated v, omega (u_stokes, v_stokes, w_stokes, ubar_stokes, bar_stokes, omega_stokes, [m/s])}, significant wave height (Hwave, [m]), mean wind wavelength (Lwave, [m]), peak surface wave period (Pwave_top, [s]), wind bottom wave period (Pwave_bot, [s]), bottom orbital velocity (Uwave_rms, [m/s]), surface roughness factors {Charnok, wave amplitude}, surface fluxes due to wave dissipation and Craig and Banner wave breaking. Other variables include the vertical coordinate system transformation variables, time steps, mixing/drag/dissipation/stability/buoyancy production/shear production/breaking wave coefficients, nudging time scales, sponge layer/tracers/point source switches, and Coriolis parameter. The WRF parameters include land/lake/water masks, SST [K], sea surface oil tracer concentration [kg/m^3], sea surface oil coverage fraction; base and perturbation geopotential [m^2/s^2]; pressure [Pa], and dry air mass [Pa], U and V at 10 m [m/s], potential temperature [K] and Qv [kg/kg] at 2m [K]; water/cloud water/rain water/ice/snow/graupel mixing ratios [kg/kg], annual max/min vegetation fraction, land use category; x, y, and z wind components [m/s]; annual max albedo, soil temperature [K]/moisture [m^3/m^3]/liquid water [m^3/m^3]/relative moisture, surface and underground runoff [mm]; sea ice flag, sea surface wave heights [m]/peak wave length [m]/peak wave period [s], temperature [K]/skin temperature [K]/zonal and meridional currents [m/s]; functions describing orographic geometries, accumulated total cumulus/shallow cumulus/grid scale precipitation [mm], snow and ice, graupel, and hail; cloud fraction; short and long wave fluxes (downward, net, normal, accumulated, clear sky, instantaneous at ground and top) [W/m^2], albedo, surface emissivity, roughness length, soil temperature [K], planetary boundary layer height [m], upward heat/moisture/latent heat/accumulated heat/ at surface [W/m^2].

Methods:

The ocean model was initialized from the 1/12° global HYCOM/NCODA model. It includes nine tidal constituents imposed at lateral open boundaries drawn from ADCIRC data; wave-induced stresses, currents, and dissipation using the vortex-force formalism, and a generic length-scale turbulence closure scheme. Oil is treated as a passive tracer. The SWAN wave model shares the ROMS horizontal grid. Significant wave height, peak period, and average direction at the peak periods are specified every 20 km along lateral open boundaries and updated every three hours; data are drawn from the 10 arc minute Northern Atlantic regional grid WaveWatch3 model (ftp://polar.ncep.noaa.gov/pub/history/waves). Further details of the component coupled models can be found in the included descriptive document.

Individual Files: