Dr. Tamay M. Özgökmen at the University of Miami was awarded an RFP-I grant at $15,296,000 to lead the GoMRI Consortium for Advanced Research on Transport of Hydrocarbon in the Environment (CARTHE) that consisted of 16 collaborative institutions and 95 research team members. The goal of CARTHE was to accurately predict the fate of hydrocarbons released into the environment. CARTHE’s scientific work focused on the physical distribution, dispersion, and dilution of petroleum, its constituents, and associated contaminants under the action of physical oceanographic processes, air-sea interactions, and tropical storms. The aim was to better predict where the spill is going and how fast it is spreading so that emergency responders can better allocate limited resources to minimize the immediate impact from surface oil on beaches and to minimize impacts on society, the economy, and health.
Over its award period (3 years, plus a 12-month no-cost extension), CARTHE organized nearly 400 outreach activities or products, including but not limited to:
- CARTHE partnered with the Dranoff 2 Piano Foundation on the Piano SLAM poetry competition to inspire middle and high school students to write science-inspired poetry.
- High school students from several Florida schools (MAST Academy, South Broward High School, Rickards High School) worked with CARTHE scientists to design and build their own drifters in preparation for the Surfzone Coastal Oil Pathways Experiment (SCOPE). In this coastal experiment, CARTHE scientists wanted to know how the currents and waves affect the movement of oil and other toxins onto shore. Students were challenged to create new and improved drifters that can help scientists answer these tough but important questions.
- For K12 audiences, CARTHE partnered with Waterlust to develop the “Bob the Drifter” and “Drones at the Beach” videos, which were two of the finalists in the 2015 Ocean 180 Video Challenge. The latter video won this competition based on the votes of about 38 thousand middle school students.
- CARTHE scientists regularly shared their research at rotary clubs, fishing clubs, and various community events.
As of December 31st, 2015,CARTHE research, which entailed 3 large research cruises or expeditions, has resulted in 72 peer-reviewed publications, 145 scientific presentations and 44 datasets being submitting to the GoMRI Information and Data Cooperative (GRIIDC), which are/will be available to the public. CARTHE engaged 32 students over its award period. Significant outcomes of CARTHE research are highlighted below according to the distance from the Deepwater Horizon (DWH) spill:
- A substantial effort was focused on the “first mile”, namely the near-field modeling of the multi-phase plume associated with subsea spills. By exploiting the highly turbulent nature of the DWH plume, highly-resolved multi-phase plumes simulations are conducted using a single set of momentum equations, leading a great degree of computational simplification while retaining the turbulent complex character of the plume dynamics. Using these simulations, it was shown that the DWH plume was influenced by the Earth’s rotation and possibly changed the flow field in its environment. CARTHE investigators found that the Coriolis force impacts the plume in a way very similar to a top (the gyroscopic kid’s toy), where, due to angular momentum conservation, the top assumes a precession in addition to the spin around its axis of tilted rotation. The impact of such a precession is rather dramatic in deep ocean plumes because any tilt from the vertical causes gas to escape (due to slip velocity) and significantly different turbulence far away from the source location.
- In addition, in-situ observations of water column organic dissolved carbon showed oil contamination at the depth of the DWH plume in 2014, some four years after the spill.
- CARTHE conducted Grand Lagrangian Deployment (GLAD) in which 300 surface drifters were deployed over 10 days. GLAD was the largest synoptic upper ocean dispersion experiment conducted to date in oceanography. GLAD demonstrated that massive synoptic releases of surface drifters is a technologically-feasible technique to quantify transport pathways under the influence of wind, waves and ocean currents.
- This technique was put in practice during the 2013 Hercules blowout when CARTHE drifters were helpful in guiding a substantial biochemical and hydrological sampling campaign with other GoMRI scientists that was launched with a few days after the event.
- On the basis of GLAD, CARTHE scientists have revealed that oceanic processes on scales of less than few kilometers and faster than a day have a significant impact on the dispersion of buoyant tracers in the DeSoto Canton, near the vicinity of the DWH oil spill. It was also found that these processes are either missing or under-resolved in current generation ocean models and satellite altimeter observing systems.
- Drifter assimilation schemes were developed to correct model flow fields. Also a method to fuse drifter and altimeter data sets was implemented for the Gulf of Mexico. Collaboration was established with a NASA/JPL team working on next generation satellite sensors for providing ground truth.
- CARTHE researchers found that many of the statistical characteristics of dispersion in the GLAD experiment were similar to those from canonical dye releases in rivers and lakes, laboratory experiments and atmospheric plume observations dating back to 1926. This striking result implies a generality of the scaling laws over many scales.
- Using drifter data during the passage of Hurricane Isaac, significant deviation from these traditional dispersion scaling laws was demonstrated. Thereby, using the same long GLAD data set, CARTHE researchers not only extended the validity of classical dispersion laws to much larger scales than before, but have also shown under which circumstances these laws are not valid anymore.
- In order to investigate transport processes during the “last mile”, CARTHE conducted the Surfzone Coastal Oil Pathways Experiment. SCOPE showed that coastal discharges from inlets, bays, and estuaries along the northeast Gulf of Mexico can act as a transport barrier near the coastal zones. The propagation of the coastal frontal zone near the Destin Inlet was analyzed, and it was found that the upper 2 m plume contains turbulent kinetic energy dissipation rates that are some three orders of magnitude higher than the ambient flow. It was shown that numerical models need to capture fine inlet geometry and outflows dynamics in order to realistically simulate near-shore pollutant transport. These dynamics are important to interpret the irregular distribution of oil along coastal zones affected by the DWH incident.
- Submesoscale processes, Stoke’s drift, and clustering by surface convergence zones have been identified by CARTHE investigators to exert a significant process on surface material transport on the basis of both open ocean (GLAD) and coastal (SCOPE) experiments.
- GLAD dataset revealed a new scaling relationship for the temperature dissipation rate in the upper ocean, as well as a characterization of the effect of wind on different types of waves (capillary and gravity-capillary).
- CARTHE scientists have also developed adaptive mesh refinement for storm surge models of the Gulf of Mexico coast, as computational speed is critical to response.
Project Research Overview (2015):
An overview of the project research activities from the GoMRI 2015 Meeting in Houston.
Direct link to the Research Overview presentation.
Proposed Research Overview (2011):
For an overview of the proposed research, see the Proposed Research Overview presentation from the GoMRI Fall 2011 Meeting in New Orleans.