Abstract:

The dataset contains the numerical results of probabilistic forecasts for possible oil spills in the Cuban Western Continental Shelf and two animation figures (*.gif) of model results. The origin of possible oil spills scenarios is deep wells proposed to operate in and around Cabo San Antonio. Oil dispersal and concentrations were simulated using the latest updated version of the oil application of the Connectivity Modeling System (CMS) or oil-CMS. In this version, the specified hydrocarbon pseudo-components are in the same droplet. The post-processing analysis yielded 4-D spatiotemporal data of the oil concentrations and oil mass on a regular horizontal and vertical grid, as well as the time evolution of the horizontally cumulative oil mass for a period of about 6 months. In the present oil spill scenario, a deep-sea blowout is modeled at 22.08N, 85.10W, the oil droplets are released at 1222m depth, or 300m above the hypothetical oil well, in similarity to Deepwater Horizon disaster in 2010. 3000 oil droplets were released every 2 hours for 87 days, equivalent to a total of 3132000 oil droplets released during the simulation. Initial droplet sizes were determined at random by the CMS in the range of 1-500 micron. Each oil droplet contained three (3) pseudo-components accounting for the differential oil density as follows: 10% of light oil with the density of 800kg/m^3, 75% of the oil with 840 kg/m^3, and 15% of heavy oil with 950 kg/m^3 density. The half-life decay rates of oil fractions were 30 days, 40 days, and 180 days, respectively. The surface evaporation half-life was set to 250 hours; horizontal diffusion was set to 10 m^2/s. Ocean hydrodynamic forcing for the CMS model was coming from the HYbrid Coordinate Ocean Model (HYCOM) for the Gulf of Mexico region on a 0.04-deg. horizontal grid and 40 vertical levels from the surface to 5500m. HYCOM provided daily average 3-D momentum, temperature and salinity forcing fields to the CMS model. The surface wind drift parameterization used surface winds and wind stresses from the 0.5-degree Navy Operational Global Atmospheric Prediction System (NOGAPS). The transport and evolution of the oil droplets were tracked by the oil-CMS model during the 167 days of the simulation, recording each particle’s horizontal position, depth, diameter, and density into the model output file every 2 hours. Model data had to be post-processed to obtain oil concentrations estimates. The post-processing algorithm took into account the total amount of oil spilled during the 87-day incident as estimated from the reports (730000 tons). Results from the recent laboratory deep-pressure oil experiment and from the observational studies in post-Deepwater Horizon disaster were used to adopt presumed initial droplet size distribution (DSD) for the cases of untreated oil and for the oil treated with a subsea injection of chemical dispersants. The post-processing algorithm then utilized the change-of-variable technique for the probability density functions to obtain an oil mass distribution from a known DSD. A scaling factor was further determined to obtain a representative particle mass and then the volumetric concentration in water. Two postprocessing options were assumed with different initial DSD, corresponding to the untreated oil, and oil treated with subsea dispersant injection (SSDI) that shifts the modal peak in DSD to a smaller droplet. This dataset supports the publications: Paris, C. B., Vaz, A. C., Berenshtein, I., Perlin, N., Faillettaz, R., Aman, Z. M., & Murawski, S. A. (2019). Simulating Deep Oil Spills Beyond the Gulf of Mexico. Scenarios and Responses to Future Deep Oil Spills, 315–336. doi:10.1007/978-3-030-12963-7_19; and Paris, C. B., Murawski, S. A., Olascoaga, M. J., Vaz, A. C., Berenshtein, I., Miron, P., & Beron-Vera, F. J. (2019). Connectivity of the Gulf of Mexico Continental Shelf Fish Populations and Implications of Simulated Oil Spills. Scenarios and Responses to Future Deep Oil Spills, 369–389. doi:10.1007/978-3-030-12963-7_22.

Suggested Citation:

Natalie Perlin. 2019. Three-dimensional daily hindcast of oil concentrations and oil mass estimates from the far-field modeling of a deepwater oil spill scenario in the Cuban Continental Shelf, using the Connectivity Modeling System on a probabilistic approach. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/n7-ftgf-qb84

Publications:

Paris, C. B., Murawski, S. A., Olascoaga, M. J., Vaz, A. C., Berenshtein, I., Miron, P., & Beron-Vera, F. J. (2019). Connectivity of the Gulf of Mexico Continental Shelf Fish Populations and Implications of Simulated Oil Spills. Scenarios and Responses to Future Deep Oil Spills, 369–389. doi:10.1007/978-3-030-12963-7_22

Paris, C. B., Vaz, A. C., Berenshtein, I., Perlin, N., Faillettaz, R., Aman, Z. M., & Murawski, S. A. (2019). Simulating Deep Oil Spills Beyond the Gulf of Mexico. Scenarios and Responses to Future Deep Oil Spills, 315–336. doi:10.1007/978-3-030-12963-7_19

Purpose:

To provide state-of-the-art modeling data of the far-field of the scenario of potential deepwater oil blowout in Gulf of Mexico, similar in magnitude to the 2010 Deepwater Horizon oil spill. This scenario is for the blowout location in the Cuban Western Continental Shelf. To be used as a spatiotemporal input data for ecosystem modeling applications, and other first-response and environmental policy questions.

Data Parameters and Units:

Parameters: Oil_conc [Oil concentration; parts per billion (ppb)]; Time [time, seconds from release]; lat [Latitude, degrees north], lon [Longitude, degrees east]; oil_mass [kg of crude oil], depth [meters]. Time scale for the 3D oil concentrations: daily averages. 3D data is given for the "untreated oil" case only. Horizontal grid: 0.02-degree spacing, 18.1N-31.0N, 98W-77W. Vertical grid: 127 levels as following: 0-1m, 1-20m, from 20 to 2500 at 20m, increments, and then 2500-4500m. Time scale for horizontally-cumulative oil mass: 2-h intervals (7200s). The data for the surface oil concentrations are daily average values in ppb units; the oil mass units are kg of crude oil. Horizontal grid boxes are 0.02 degrees covering the entire Gulf of Mexico domain and beyond (18.1N-31.0N, 98.0W-77.0W), and vertical grid extends from the surface to the depth of 2500m at 20m increments, except for the top two layers which are 0-1m and 1-20m, and below 2500m. The data for horizontally-cumulative oil mass are in units of kg of crude oil, distributed in the water column on a vertical grid from the surface down to 2500m at 20m increments, and estimated bi-hourly corresponding to the oil-CMS model output interval. Post-processed NetCDF files were created using the Matlab software package, v. R2016b. The data files with the 3-D data used compression capability of the NetCDF to keep the file size small; maximum compression or ‘DeflateLevel’ = 9 was used. Numerical simulations and post-processing were performed using a Pegasus supercomputer at the Center of Computational Science, University of Miami, in 2018. The data file in *.txt files lists all the droplets that landed or beached within the simulation domain (and no longer are advanced by the CMS model). Format of the files is the following: the first column is the time in seconds from the initial blowout time, the second column is a depth of a landed particle, the third column is the latitude, the fourth column is the longitude, and the last column is a scaled oil mass of the particle in kg. There are two animated *.gif files with visualization of model results. One is for showing the surface daily oil concentrations (in ppb), and surface ocean currents for the corresponding day in the Gulf of Mexico and the region around the blowout site. The other animation is 3-D animated view zooming on the rising oil plume, showing isosurfaces of 1000 ppb, 100 ppb, and 10 ppb; surface concentrations are shown using a color scheme.

Individual Files: