Influence of river induced fronts on hydrocarbon transport addresses Theme 1 of the Gulf of Mexico Research Initiative (GOMRI) aiming towards a comprehensive observational and modeling study on hydrocarbon transport in areas of river influence. The overarching study objective is to understand, quantify and be able to predict the role of river plume induced fronts and circulation regimes in enhancing, modifying or altering the transport pathways of hydrocarbons, in the presence of complex topography, shelf flows and strong oceanic currents. Strong evidence has emerged that such fronts and currents played a crucial, but poorly understood, role controlling oil pathways in the Gulf of Mexico (GoM) during the Deepwater Horizon (DwH) incident. The study area will cover the entire GoM, including the Florida Straits. Two major hypotheses will be examined: a) large river plumes create distinct circulation regimes, separated with strong fronts that are of fundamental importance for hydrocarbon transport; b) accurate estimates of hydrocarbon pathways need to take into account the thickness of oil. This study will show under what conditions river plumes may help entrain oil and guide it toward the coastline (prevailing case west of the Mississippi Delta) or may help push oil offshore, acting as a barrier for onshore pathways (prevailing case east of the Mississippi Delta). The latter is also connected to river plume interaction with offshore flows, specifically the Loop Current (LC) system.
Scientific merit: This project proposes to employ novel analyses of satellite data, targeted field surveys, and data-guided, high resolution physical, biochemical and oil spill simulations to explore details on hydrocarbon transport, with updated methodologies to estimate and model oil thickness. Both the true conditions of the DwH incident and a variety of relevant alternative scenarios will be studied. A known active leakage site, the Taylor Energy platform near the Mississippi Delta (leaking oil since 2004) will be used for in situ estimates of oil spreading and thickness under different conditions in the surrounding environment, which is dominated by Mississippi influence and LC intrusions. These in situ data will then be used to calibrate oil thickness estimation from remote sensing, allowing a more accurate initialization of the proposed oil spill simulations. This approach will fill important knowledge gaps and result in advanced understanding of the conditions controlling the complex hydrocarbon pathways in the GoM. The PIs have proven track records of specific research accomplishments in the GoM. In particular, they have contributed to the ability to observe and predict unprecedented details in fronts induced by the highly variable, low-salinity, turbid Mississippi waters and the variability in the evolution of the LC and associated eddy field. They have shown how the LC controls connectivity pathways between the Northern GoM and the Florida Straits, which often carry waters of Mississippi origin toward remote ecosystems, such as the ecologically sensitive coral reefs in the Florida Keys. Could hydrocarbons from a potential oil spill in the Northern GoM follow similar routes? What is the role of fronts and jets that are known to be induced from the LC interaction with the Mississippi River plume to initiate such offshore pathways? How would the thickness of the hypothetical oil spill influence the ability to reach remote coastal areas?
Expected outcomes are to:
- Understand how fronts and circulation due to river plumes influence hydrocarbon transport
- Derive methodology to: a) measure oil spill extent and thickness, combining satellite products and in situ measurements; b) perform oil spill simulations that accommodate data-derived oil thickness.
This project is well focused on: a) understanding specific processes impacting hydrocarbon transport in the GoM, which are currently not well understood; b) accommodating a specific oil parameter (thickness) that has been challenging to estimate and, therefore, largely missing in oil spill prediction. Results will thus be of fundamental importance both scientifically and for resource management and disaster response. Outcomes of the proposed methodology development and the overall study products will be fully available to the GOMRI community and are expected to be an important component in GOMRI’s mission. Outreach products will engage both the local coastal communities and the international science community, through the GODAE OceanView Coastal and Shelf Seas Task Team co-chaired by the PI. Educational products include middle-school science class material (activity initiated with teacher mentoring in previous GOMRI funding), as a tool to motivate student career paths in STEM fields.
Project Research Overview (2016):
An overview of the proposed research activities from the GoMRI 2016 Meeting in Tampa.
Direct link to the Research Overview presentation.