Study Documents How Riverine Fronts Influence Oil Transport Pathways
September 11, 2018
Scientists used drifters, drones, satellite imagery, and air/water measurements to investigate how local and regional ocean processes in the Gulf of Mexico influence where surface oil from the leaking Taylor Energy Site travels. The multiplatform observations documented three distinct transport pathways created by fronts, which developed from strong density differences between brackish water masses and clearer high-salinity ocean waters. Multiple river fronts influenced the final destinations of drifters and oiled waters, trapping and directing them either westward or eastward and preventing them from reaching the Mississippi River Delta. The team measured and evaluated oil thickness and updated oil drift algorithms, which, for the first time, are being included in high resolution model simulations of circulation and oil drift and could greatly improve future oil transport monitoring and predictions. The researchers published their findings in the Journal of Geophysical Research: Oceans: Influence of river‐induced fronts on hydrocarbon transport: A multiplatform observational study.
The Taylor Energy Site is near the Mississippi River Delta and its oil rig was damaged by Hurricane Ivan in 2004. Since then, oil slicks and sheens have persistently formed on the sea surface around the site, providing a natural laboratory for studying oil slick interactions with riverine fronts. Understanding the dynamic physical processes in this region is important because oil exploration often takes place near river deltas around the world.
The team conducted their field work in April 2017, tracking rapid changes of spreading oil in tandem with changes in riverine fronts and surface currents. Their multiplatform experiment included drifters (some developed by the CARTHE research group and some provided by the Norwegian Meteorological Institute), shipboard radar sea-surface roughness imagery, thermohaline measurements, and high-resolution satellite data from multiple sensors. The team derived transport pathways from drifter trajectories and derived the distribution of surface currents and spreading oil from marine radar and high-resolution satellite data, which also detected multiple river fronts.