Abstract:

This dataset contains four of the nine sets of model output resulting from an investigation on the effects of horizontal and vertical resolution on model representation of tracer dispersion along the continental slope in the northern Gulf of Mexico. The investigation involved a collaborative effort between the Ecosystem Impacts of Oil and Gas Inputs to the Gulf (ECOGIG) and Gulf of Mexico Integrated Spill Response (GISR) research consortia. This dataset contains the GISR-funded contribution to the study. The model output from the remaining five datasets will be submitted separately by ECOGIG. This dataset supports the publication: Bracco, A., Choi, J., Kurian, J., & P. Chang. (2018). Vertical and horizontal resolution dependency in the model representation of tracer dispersion along the continental slope in the northern Gulf of Mexico. Ocean Modelling, 122: 13-25. doi: 10.1016/j.ocemod.2017.12.008

Suggested Citation:

Jaison Kurian, Ping Chang. 2018. Dataset for: Vertical and horizontal resolution dependency in the model representation of tracer dispersion along the continental slope in the northern Gulf of Mexico. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N75D8Q9V

Publications:

Bracco, A., Choi, J., Kurian, J., & Chang, P. (2018). Vertical and horizontal resolution dependency in the model representation of tracer dispersion along the continental slope in the northern Gulf of Mexico. Ocean Modelling, 122, 13–25. doi:10.1016/j.ocemod.2017.12.008

Chapman, P., DiMarco, S., Hetland, R., & Socolofsky, S. (2018). From Bubbles to Beaches: An Integrated Modeling Approach to Oil Spill Response. Marine Technology Society Journal, 52(6), 91–94. doi:10.4031/mtsj.52.6.4

Purpose:

The horizontal and vertical resolution of model grids can affect the modeled tracer dispersion. This study employed 9 model runs with differing resolutions to evaluate the effect on horizontal transport and mixing of a simulated passive tracer.

Data Parameters and Units:

ntimes (number of long time-steps; unitless), ndtfast (number of short time-steps; unitless), dt (size of long time-steps; second), dtfast (size of short time-steps; second), dstart (time stamp assigned to model initialization; days since 2012-07-18 00:00:00), nHIS (number of time-steps between history records; unitless); ndefHIS (number of time-steps between the creation of history files; unitless), nRST (number of time-steps between restart records; unitless), nRST (only latest two records are maintained; unitless), ntsAVG (starting time-step for accumulation of time-averaged fields; unitless), nAVG (number of time-steps between time-averaged records; unitless), ndefAVG (number of time-steps between the creation of average files; unitless), ntsDIA (starting time-step for accumulation of diagnostic fields; unitless), nDIA (number of time-steps between diagnostic records; unitless), ndefDIA (number of time-steps between the creation of diagnostic files; unitless), Falpha (Power-law shape barotropic filter parameter; unitless), Fbeta (Power-law shape barotropic filter parameter; unitless), Fgamma (Power-law shape barotropic filter parameter; unitless), nl_tnu2(nonlinear model Laplacian mixing coefficient for tracers; meter^2/s), nl_visc2 (nonlinear model Laplacian mixing coefficient for momentum; meter^2/s), Akt_bak(background vertical mixing coefficient for tracers; meter^2/s ), Akv_bak (background vertical mixing coefficient for momentum; meter^2/s ), Akk_bak (background vertical mixing coefficient for turbulent energy; meter^2/s), Akp_bak (background vertical mixing coefficient for length scale; meter^2/s) rdrg (linear drag coefficient; m/s), rdrg2 (quadratic drag coefficient; unitless), Zob (bottom roughness, m), Zos (surface roughness; m), Znudg (free-surface nudging/relaxation inverse time scale; 1/day), M2nudg (2D momentum nudging/relaxation inverse time scale; 1/day), M3nudg (3D momentum nudging/relaxation inverse time scale; 1/day), Tnudg (Tracers nudging/relaxation inverse time scale; 1/day), FSobc_in (free-surface inflow, nudging inverse time scale; 1/second), FSobc_out (free-surface outflow, nudging inverse time scale; 1/second), M2obc_in(2D momentum inflow, nudging inverse time scale; 1/second); M2obc_out (2D momentum outflow, nudging inverse time scale; 1/second), Tobc_in (tracers inflow, nudging inverse time scale; 1/second), M3obc_in (3D momentum inflow, nudging inverse time scale; 1/second), M3obc_out (3D momentum outflow, nudging inverse time scale; 1/second), rho0 (mean density used in Boussinesq approximation; kg/m^3), gamma2 (slipperiness parameter; unitless), spherical (grid type logical switch; flag_values = 0,1; flag_meanings = Cartesian spherical), xl (domain length in the XI-direction; m), el (domain length in the ETA-direction; m), Vtransform (vertical terrain-following transformation equation; unitless), Vstretching (vertical terrain-following stretching function; unitless), theta_s (S-coordinate surface control parameter; unitless), theta_b (S-coordinate bottom control parameter; unitless); Tcline (S-coordinate surface/bottom layer width; m), hc (S-coordinate parameter, critical depth; m); s_rho (S-coordinate at RHO-points), s_w (S-coordinate at W-points), Cs_r (S-coordinate stretching curves at RHO-points), Cs_w (S-coordinate stretching curves at W-points), h (bathymetry at RHO-points; meter), f (Coriolis parameter at RHO-points; 1/second), pm (curvilinear coordinate metric in XI; 1/m), pn (curvilinear coordinate metric in ETA; 1/m), lon_rho (longitude of RHO-points; degree_east), lat_rho (latitude of RHO-points; degree_north), lon_u (longitude of U-points; degree_east), lat_u (latitude of U-points; degree_north), lon_v (longitude of V-points; degree_east), lat_v (latitude of V-points, degree_north), lon_psi (longitude of PSI-points; degree_east), lat_psi(latitude of PSI-points; degree_north), mask_rho (mask on RHO-points; flag_values = 0,1; flag_meanings = "land water"), mask_u (mask on U-points; flag_values = 0,1; flag_meanings = "land water"), mask_v (mask on V-points; flag_values = 0,1; flag_meanings = "land water"), mask_psi (mask on psi-points; flag_values = 0., 1. ;flag_meanings = "land water"), ocean_time (averaged time since initialization; seconds since 2012-07-18 00:00:00), zeta(time-averaged free-surface; m), ubar (time-averaged vertically integrated u-momentum component; m/s), vbar (time-averaged vertically integrated v-momentum component; m/s), u (time-averaged u-momentum component, m/s), v (time-averaged v-momentum component, m/s), w (time-averaged vertical momentum component; m/s), temp (time-averaged potential temperature; deg. C), salt (time-averaged salinity; unitless), dye_01(time-averaged dye concentration, type 01; kg/m^3), rho (time-averaged density anomaly; kg/m^3), AKv (time-averaged vertical viscosity coefficient; m^2/s), AKt (time-averaged temperature vertical diffusion coefficient; m^2/s), latent (time-averaged net latent heat flux; W/m^2), sensible (time-averaged net sensible heat flux; W/m^2), lwrad (time-averaged net longwave radiation flux; W/meter^2), sward (time-averaged solar shortwave radiation flux; W/meter^2), sustr (time-averaged surface u-momentum stress; newton/m^2), svstr (time-averaged surface v-momentum stress; newton/m^2)

Methods:

Directory names correspond to the ROMS experiment names used in Bracco, A., Choi, J., Kurian, J., & P. Chang. (2018). Vertical and horizontal resolution dependency in the model representation of tracer dispersion along the continental slope in the northern Gulf of Mexico. Ocean Modelling, 122: 13-25. doi: 10.1016/j.ocemod.2017.12.008. There are 4 folders: exp_3km_25, exp_3km, exp_3km_80, exp_3km_150. The number 25, 80, and 150 in the folder name stands for vertical discretization in four different ROMS configurations with 25, 80 and 150 layers. The folder exp_3km stands for 50 vertical discretization layers. At the more conservative 3 km horizontal resolution, we also explored the role of vertical discretization in four different ROMS configurations with 25, 50, 80 and 150 layers. The lowest vertical resolution is at the lower limit of what adopted in the last Coupled Model Intercomparison Project (CMIP5); about 50 layers are commonly used in regional and global mesoscale-resolving applications; 80 layers are at the upper limit of what adopted in regional simulations; and 150 layers is the target set in this work to verify the existence of convergence for increasing vertical resolution. The tracer dimension in ROMS output NetCDF file is the total number of tracers (active + passive). For all experiments, we have 2 active tracers (temperature and salinity). For exp_3km_150, we have 4 passive tracers (dye_01, dye_02, dye_03 and dye_04). For all other experiments, we only have 1 passive tracer (dye_01). For the paper we used only the "dye_01" variable, which corresponds to passive tracer released close to 1060m depth in the model. For some experiments, we have released passive tracers at few other levels too but not analyzed for the current paper/manuscript.

Individual Files: