Abstract:

This data is from a ROMS (http://www.myroms.org) free-running simulation of the De Soto Canyon region in the North East Gulf of Mexico. The simulation covers the time span January 2010 through March 2013. The vertical grid is stretched to focus vertical resolution near the surface and the horizontal grid has 1km resolution. CFSR data are used for the surface forcing and the model is nested in a data-assimilative global HYCOM model. Rivers are included through point sources with temperature, salinity and momentum fluxes specified and derived from USGS and NOAA data.

Suggested Citation:

Hiester, Hannah. 2016. Regional Ocean Modeling System (ROMS) 1km Model, De Soto Canyon, January 2010-March 2013. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N71V5C0S

Purpose:

The dataset was developed to study river water spreading in the North East Gulf of Mexico.

Data Parameters and Units:

- ocean_time: time in seconds since 1900-12-31 00:00:00; - lon_rho, lon_u, lon_v, lon_psi: longitude for rho, u , v and psi points, respectively, in degrees; - lat_rho, lat_u, lat_v, lat_psi: latitude for rho, u , v and psi points, respectively, in degrees; - mask_rho, mask_u, mask_v, mask_psi: land mask for rho, u , v and psi points, respectively, with 0 and 1 for land and water respectively; - h: bathymetry depth in m; - temp: water temperature in degrees celsius; - salt: salinity in psu; - u: horizontal velocity in x (longitude) direction in m/s; - v: horizontal velocity in y (latitude) direction in m/s; - w: vertical velocity in m/s; - zeta: free surface height in m; - Akt: vertical temperature diffusion coefficient in m²/s; - Aks: vertical salinity diffusion coefficient in m²/s; - Cs_r, Cs_w: s-coordinate stretching curves at rho and w points, respectively; - s_rho, s_w: vertical s-coordinate ar rho and w points, respectively; - pm, pn: curvilinear coordinate metric in xi and eta, respectively, in 1/m; - spherical: spherical grid configuration (True/False);

Methods:

The dataset was generated by a configuration of the Regional Ocean Modeling System (ROMS, version 451, http://www.myroms.org). The simulation was run in parallel on 64 processors on the Florida State University High Performance Computing Cluster (https://rcc.fsu.edu/). ROMS overview: ROMS is a finite-difference primitive equation ocean circulation model that employs the hydrostatic and Boussinesq approximations (Shchepetkin & McWilliams, 2005; Shchepetkin & McWilliams, 2003). ROMS uses sigma coordinates in the vertical that can be stretched to allow increased resolution in areas of interest (Song & Haidvogel, 1994). River input is generally treated as a temperature, salinity and momentum source distributed over the vertical (http://www.myroms.org). Domain, bathymetry and spatial resolution: The domain that extends from -90.5⁰W to -84.5⁰W and 27.2⁰N to 30.7⁰N. 1km resolution is used in the horizontal. The bathymetry is extracted from a high resolution Gulf of Mexico bathymetry and smoothed once using a nine-point-average filter. The high resolution Gulf of Mexico bathymetry product is available at http://deep-c.org/data/tabular/models. The minimum depth is 3m. In the vertical, 40 layers are used with stretching designed to increase resolution near the surface and focus resolution on the upper part of the water column, which is most affected by river inflow. This gives vertical resolution ranging from approximately 0.01m to 2m at the surface (in shallower and deeper parts of the domain) and 12m at the bottom in the deepest regions of the domain. The stretching parameters and transformation equation options are theta_s=8.0, theta_b=0.0 and h_c=100.0, Vtransform=2 and Vstretching=4, see http://www.myroms.org for more details. Discretization: Horizontal and vertical momentum are discretized using a third-order upstream advection scheme and a fourth-order centered difference scheme respectively with the vertical pressure gradient calculated from a reconstructed vertical density gradient. Tracer advection is discretized using a Multidimensional Positive Definite Advection Transport Algorithm (MPDATA) that conserves mass and limits over and undershoots (Smolarkiewicz, 1983; Smolarkiewicz & Clark, 1986) with harmonic Laplacian horizontal diffusion along density surfaces. The internal model time step is 90 s with 30 fast external mode time steps per internal time step. Forcing and boundaries: The open boundaries are forced using a nesting approach with boundary values relaxed exponentially on a 3 hourly time scale over a 55km buffer zone (included in the dataset) to data from a 1/12⁰ data-assimilative global HYCOM model (http://hycom.org). Atmospheric forcing (10m wind speed, 2m air temperature and humidity, shortwave radiation and cloud cover) is derived from the Climate Forecast Reanalysis System (CFSR, Saha et al. 2010) and fluxes are computed using a bulk flux formulation (Fairall et al., 1996). Daily average discharges are calculated from US Geological Survey data for 9 rivers in the domain and a temperature climatology is calculated from National Ocean Atmospheric and Administration tides and currents buoy data (http://tidesandcurrents.noaa.gov) and is available at http://deep-c.org/data/tabular/models. Other: A nonlinear equation of state is used. A Jerlov water type III is used. References: Fairall, C. W., Bradley, E. F., Rogers, D. P., Edson, J. B., & Young, G. S. (1996). Bulk parameterization of air-sea fluxes for tropical ocean-global atmosphere Coupled-Ocean Atmosphere Response Experiment. Journal of Geophysical Research , 101, 3747-3764. Saha, S., Moorthi, S., Pan, H.-L., Wu, X., Wang, J., Nadiga, S., Tripp, P., Kistler, R., Woollen, J., Behringer, D., Liu, H., Stokes, D., Grumbine, R., Gayno, G., Wang, J., Hou, Y.-T., Chuang, H.-Y., Juang, H.-M. H., Sela, J., Iredell, M., Treadon, R., Kleist, D., Van Delst, D., Keyser, D., Derber, J., Ek, M., Meng, J., Wei, H., Yang, R., Lord, S., Van Den Dool, H., Kumar, A., Wang, W., Long, C., Chelliah, M., Xue, Y., Huang, B., Schemm, J.-K., Ebisuzaki, W., Lin, R., Xie, P., Chen, M., Zhou, C.-Z., Liu, Q., Chen, Y., Han, Y., Cucurull, L., Reynolds, R. W., Rutledge, G., Goldberg, M. (2010). The NCEP Climate Forecast System Reanalysis. Bulletin of the American Meteorological Society , 91 (8), 1015-1057. Shchepetkin, A. F., & McWilliams, J. (2003). A method for computing horizontal pressure-gradient force in an oceanic model with a nonaligned vertical coordinate. Journal of Geophysical Research , 108 (C3). Shchepetkin, A. F., & McWilliams, J. C. (2005). The Regional Ocean Modeling System: A split-explicit, free-surface, topography following coordinates ocean model. Ocean Modelling , 9, 347-404. Smolarkiewicz, P. K. (1983). A Simple Positive Definite Advection Scheme with Small Implicit Diffusion. Monthly Weather Review , 111, 479-486. Smolarkiewicz, P. K., & Clark, T. L. (1986). The multidimensional positive definite advection transport algorithm: Further development and applications. Journal of Computational Physics , 67, 396-438. Song, Y., & Haidvogel, D. B. (1994). A semi-implicit ocean circulation model using a generalized topography-following coordinate system. Journal of Computational Physics , 115 (1), 228-244.

Individual Files: