Dataset for: A Coupled Lagrangian-Earth System Model for Predicting Oil Photooxidation

The explosion of the Deepwater Horizon (DWH) oil drilling rig on April 20 of 2010 in the Gulf of Mexico resulted in an uncontrolled oil spill from 5000 feet below the sea surface, requiring an extraordinarily rapid response. A decade ago, the technology to model oil spills from the deep ocean did not exist. A few oil models are now capable of forecasting the 3D transport and fate of the oil from such blowout. An important limitation in estimating the fate of the oil is, still today, the lack of spatially explicit photooxidation model parameterization. Weathering of oil near the sea surface depends on the physicochemical and biological characteristics of the petroleum hydrocarbons and the environment. While most fate processes, such as evaporation, dissolution, and biodegradation are well understood and typically accounted for, the effects of sunlight on photooxidation of oil are not fully modeled. During the DWH blowout, photooxidation of surface oil led to the formation of persistent oxidized compounds, still found in shoreline sediments. Additionally, studies demonstrated that photooxidation modified both biodegradation rates of the surface oil as well as the effectiveness of aerial dispersant applications. Despite the significant consequences of this weathering pathway, it was not considered in DWH oil budget calculations nor in predictive models. Here we develop a Lagrangian photooxidation module that estimates the dose of solar radiation individual oil droplets receive while moving in the ocean, and quantifies changes in photooxidation. The dose of incoming solar radiation is computed with the intensity of the surface irradiance from the earth system model NOGAPS (Navy Operational Global Atmospheric Prediction System), the coefficient of absorption (Kd) of specific wavelengths from the literature, and the depth of the oil droplets from the Connectivity Modeling System (CMS). Coupling the net shortwave radiation from NOGAPS to CMS, we estimate the photooxidation rates in oil droplets for the DWH case. Our new photooxidation module can be used to test hypotheses of oil fate during the DWH, and inform rapid response in future oil spills. This dataset supports the publication: Vaz, Ana C., Robin Faillettaz, and Claire B. Paris. (2021). A Coupled Lagrangian-Earth System Model for Predicting Oil Photooxidation. Frontiers in Marine Science, 8. E576747. doi:10.3389/fmars.2021.576747