Deepwater Horizon oil spill simulations using Connectivity Modeling System: Daily oil mass and concentrations on a spatio-temporal 4-D grid, surface oil concentrations, non-gridded sedimented oil mass

The dataset contains the numerical results of the 2010 Deepwater Horizon oil spill incident at Macondo well in the Gulf of Mexico, as estimated from the simulations using the latest updated version of the oil application of the Connectivity Modeling System (CMS) or oil-CMS. This contains additional data that complements the dataset that is available at GRIIDC under Unique Dataset Identifier (UDI) R4.x267.000:0084 (DOI: 10.7266/N7KD1WDB). In this version of the oil-CMS model, 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. There are two sets of simulations that last 167 days and 100 days (a shorter sensitivity run). CMS has a Lagrangian, particle-tracking framework, computing particle evolution and transport in the ocean interior. CMS simulations start date: April 20, 2010, 0000 UTC, and particles were tracked for 167 days or 100 days. Oil particles release location: 28.736N, 88.365W, depth is 1222m or 300m above the oil well. 3000 particles were released every 2 hours, for 87 days, equivalent to a total of 3132000 oil particles released during the simulation. Initial particle sizes were determined at random by the CMS in the range of 1-500 micron, and are scaled during post-processing to represent the chosen droplet size distribution (DSD). Each particle contained three (3) pseudo-components accounting for the differential oil density as follows: 10% of light oil with a 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 in the present case. Ocean hydrodynamic forcing for the CMS model was used 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. It 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 stressed from the 0.5-degree Navy Operational Global Atmospheric Prediction System (NOGAPS). The transport and evolution of the oil particles were tracked by the oil-CMS model during the 167 days of the main simulation (100 days for a sensitivity run), recording each particle’s horizontal position, depth, diameter, and density into the model output every 2 hours. Model data needed to be post-processed to obtain oil concentrations and oil mass 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), and the assumptions about the oil particle size distribution at the time of the release as estimated in the prior studies. The current dataset contains post-processed gridded and non-gridded analyses for the cases of untreated oil and cases of oil treated with the chemical dispersants at the oil release location.