Envisat radar image acquired over the Gulf of Mexico on 22 June 2010 shows that the oil spill (outlined in white) has radiated all over the Gulf of Mexico basin and is also continuing to feed into the Loop Current (red arrow). (CLS/ESA image)
Numerous universities and research organizations using the most advanced remote-sensing technologies and imaging systems have been enlisted to track the millions of gallons of oil gushing from a broken well 5,000 feet underwater in the Gulf of Mexico. Photonics experts have been working with the U.S. National Oceanic and Atmospheric Administration (NOAA) since the 20 April BP Deepwater Horizon rig disaster to monitor the movement of the oil and understand its impact on the environment and the economy.
"NOAA is using all the scientific methods at our disposal to assess the damage, from satellites in space, planes in the air, boats on the water, gliders under the sea, scientists in the field, and information online," said NOAA Administrator Jane Lubchenco.
The explosion killed 11 people, destroyed the drilling rig, and spewed millions of gallons of crude oil into the water and toward coastal areas of the United States.
Florida researchers ideally situated
Scientists at the University of South Florida's College of Marine Science, who have studied Gulf currents for decades, are using USF's sophisticated underwater imaging system, SIPPER (Shadowed Image Particle Profiling Evaluation Recorder) to assess the toxicity of the leak and its impact on the food web. The SIPPER's linescan camera can image 14 liters of water per second at 3 knots towing speed and will assess whether microscopic sea life has been damaged by the oil.
Scientists aboard the USF research vessel Weatherbird II reported in late May, and NOAA's independent analysis confirmed in June, the presence of very low concentrations of sub-surface oil and polycyclic aromatic hydrocarbons (PAHs) at sampling depths ranging from 50 meters to 1400 meters. Detectable levels of petroleum compounds had traveled as far as 42 miles northeast of the leaking well.
"The questions we are exploring are where is it, in what concentrations, where is it going, and what are the consequences for the health of the marine environment?" Lubchenco said.
NOAA's report from the Weatherbird II sampling is available online. About a dozen faculty members and 18 grad students from USF have participated in oil spill research, according to a USF spokeswoman. Among them are Ernst Peebles, an associate professor of biological oceanography. Peebles noted in a Miami Herald interview that USF was among the first to research the origin of tar balls 40 years ago. Most people assumed the oil industry was responsible, but USF showed they came primarily from ships illegally discharging crankcase oil. That led to stricter regulations in the shipping industry.
NASA watches with satellites and aircraft
NOAA is getting plenty of help from NASA and other space agencies. Envisat's Medium Resolution Imaging Spectrometer (MERIS) and Advanced Synthetic Aperture Radar (ASAR) operated by the European Space Agency, as well as WorldView-2 (USA), TerraSAR-X (Germany), RADARSAT-2 (Canada), and other instruments are being tasked to monitor the catastrophe through the International Charter Space and Major Disasters.
Data from MERIS and ASAR are being provided in near real time since April 22.
NASA deployed its instrumented research aircraft, the Earth Resources-2 (ER-2) and conducted extra satellite observations and data processing to track the movement of the oil. The ER-2 collects detailed images of threatened coastal wetlands with the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) and the Cirrus Digital Camera System.
Pilots flew the ER-2 from NASA's Dryden Flight Research Center at Edwards Air Force Base, CA, to a temporary base of operations in Houston. Along the way, the plane collected data over the Gulf coast to support spill mapping and document the condition of coastal wetlands before the oil made landfall.
The AVIRIS team, led by Robert Green of NASA's Jet Propulsion Laboratory, is measuring how the water absorbs and reflects light in order to map the location and concentration of oil, which separates into a widespread, thin sheen and smaller thick patches. Green is a frequent contributor at SPIE conferences and past chair of the Asia-Pacific Symposium on Remote Sensing of the Atmosphere, Environment, and Space. He is a co-author of five papers to be presented in August at SPIE Optics + Photonics on airborne imaging spectrometers and related topics.
Satellites can document the overall extent of the oil but cannot distinguish between the sheen and thick patches. While the sheen represents most of the area of the slick, the majority of the oil is concentrated in the thicker part. AVIRIS should be able to identify the thicker parts, helping oil spill responders know where to deploy oil-skimming boats and absorbent booms.
Another NASA research aircraft, the King Air B-200 from Langley Research Center in Hampton, VA, is collecting data with the High Spectral Resolution Lidar (HSRL). Led by Chris Hostetler of Langley, HSRL provides measurements similar to those from the CALIOP instrument on CALIPSO. Data from these space-based and airborne lidars will be used to investigate the thickness of the oil spill below the surface of the water and evaluate the impacts of dispersants used to break up the oil.
Hostetler gave a presentation at SPIE Optics+Photonics in 2009 on using HSRL for environmental monitoring.
NASA-provided satellite images are from the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments on the Terra and Aqua satellites; the Japanese Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on Terra; and the Advanced Land Imager (ALI) and Hyperion instruments on its Earth Observing-1 (EO-1) satellite. With its very wide field of view, MODIS provides a big-picture of the oil spill and its evolution roughly twice per day.
The Hyperion, ALI, and ASTER instruments observe over much smaller areas in finer detail but less often (every 2-5 days). The combination of satellite and airborne imagery will assist NOAA in forecasting the path of the oil and in documenting changes in the ecosystem.
Universities mobilize researchers
Other universities involved with the response include:
- Researchers at the University of Texas at Austin's Texas Advanced Computing Center using the Ranger supercomputer to produce 3D simulations of the impact of the oil spill on coastal areas. Marine science and engineering colleagues from the University of North Carolina in Chapel Hill and University of Notre Dame are collaborating with a massive amount of data.
- Scientists at the Center for Southeastern Tropical Advanced Remote Sensing (CSTARS) at the University of Miami, acquiring critical environmental imagery to model possible oil trajectories. The UM Rosenstiel School launched an "Oil Spill" web page to share with the public some of the science relevant to the issues emerging from the disaster: http://www.rsmas.miami.edu/oil-spill/
- Researchers at the University of Georgia using sonar and other imaging systems. They were part of the expedition that discovered toxic plumes of oil at depths ranging from 2300 to 4300 feet below the surface, despite earlier insistence from BP that oil always floats on the surface. The group's leader, Samantha Joye, is blogging about the research at http://gulfblog.uga.edu
For the latest information about the response effort, visit www.deepwaterhorizonresponse.com or http://oceanservice.noaa.gov/deepwaterhorizon.