Deepwater oil spill: Stretching the possibilities

The BP Deepwater oil spill in the Gulf of Mexico is an environmental and economic tragedy. As oil continues to spew from the well (as this is written), the innovative responses by governments, industries and the public has been unmatched to the point that one is reminded of Albert Einstein's observation: "in the middle of a difficulty lies opportunity."

National Oceanic and Atmospheric Administration (NOAA), the United States' lead science agency for the oil spill response, is tackling the "opportunity," developing novel uses for traditional geospatial tools, applying new thinking to dependable processes, and pioneering geospatial applications that are borne of desperate times. NOAA is covering all spatial and temporal dimensions – satellites in space, planes in the air, ships on the sea, and sonar beaming to the ocean floor – to provide the best available scientific advice to the full range of responders. It is not an exaggeration to say that NOAA and other US agencies are managing what may be the largest single collection of spatial data to occur, ever, with the single possible exception of NASA's collection of spatial data for the universe.

So, what is NOAA doing, geospatially speaking?

The world's satellites respond
From the beginning of the disaster, the world watched, literally, as the oil slick moved from the gushing well site to the Gulf Coast shoreline. Within hours of the blowout, NOAA was collecting and analysing imagery from satellites. Within days, the agency was coordinating imagery from other satellite providers, producing geospatial information in the form of shapefiles and animations, and providing essential experimental data to state and federal agencies.

While the public focuses attention on the US response, experts know that the US is not alone in the space-based effort. After the federal government activated the International Disaster Charter, NOAA began coordinating imagery to map surface oil spill extents, using data from satellites operated by space agencies in the US, Canada, Italy, Germany and elsewhere. In another situation, on-the-ground surveys by assessment teams were not matching well with dated shoreline imagery, since Louisiana shoreline is eroding in some places at a rate of 20 meters or more per year. NOAA cartographers applied algorithms to satellite imagery from several commercial satellites and from NOAA's Applanix Digital Sensor System to plan aerial observations that would provide contemporary shoreline data to assist the assessment teams. Uses of satellite images have ranged from highly technical to broadly accessible. While scientists pore over the images, NOAA also uses the data to produce publicly available animation showing the daily change in the extent of surface oil. The revolutionary use of satellite data has not been without challenges. NOAA scientists undertook a difficult assignment of identifying the location of oil slicks from space. For instance, medium resolution visible light images are produced when the sun's angle creates a glare off the surface of the ocean. If the glare is not wide enough, satellites cannot detect the entire plume. Because of this and other shortcomings, like the narrow swath coverage and time gaps between satellite passes, analysts use all of the data available to generate a composite over a 24-hour period.

Despite the difficulties, the wide range of satellite imagery applications is groundbreaking.

Sensors provide accurate picture
For decades, NOAA has used remote sensing technology and aerial photography to map and measure changes occurring over the country's 95,000 miles of national shoreline. Scientists knew that refinements would lead to a wide range of future capabilities that support coastal science and management and this event has reinforced that knowledge.

Agencies throughout the US government have an array of remote sensing assets. As agencies work collectively to prioritise response and recovery efforts, sensor operators on NOAA's aircraft make daily flights, equipped with state-of-theart mapping cameras. The crews have already collected thousands of baseline (pre-impact) shore and damage assessment images of coastal areas, especially focusing on the land/water interface in high-priority areas, in the effort to protect wildlife and the shoreline.

Knowledge, in and of itself, is valuable. But this ongoing crisis demonstrates the immediate connections between scientific observations and life altering decisions. As wildlife personnel, emergency responders, and lawyers attempt to assess the continuing damage, historical data is essential. NOAA's remotely sensed imagery from previous mapping projects supports ongoing assessments of shoreline features that were present prior to the spill.

Surveyors look into the water column
NOAA's predecessor organisations have been mapping the coastal seafloors since the early 19th century. Today, hydrographic vessels collect data to produce NOAA's nautical charts and to help re-open ports following hurricanes. As sonar technology improves, however, NOAA is stretching the possibilities.

Could hydrographic surveys be conducted, in essence, in the water column? Instead of focusing the sensor on the ocean floor, and characterising the conditions of the sea bottom, can hydrographers use a multi-sensor approach to detect the migration of submerged oil? What other oceanographic instrumentation can be adapted to assist in the crisis?

When approached with a proposal for research that could produce immediately helpful information, NOAA officials acted quickly. They organised a new mission to test the feasibility of using acoustic and flourometric scanning to find subsurface oil. A team of researchers from NOAA, the US Environmental Protection Agency, the University of New Hampshire, and Woods Hole Oceanographic Institution conducted the survey.

On their initial cruise, scientists observed high fluorescence and reduced dissolved oxygen anomalies more than 10 km from the wellhead. There was also a subtle acoustic anomaly, the significance of which is currently the subject of intense study, especially since, on subsequent cruises closer to the wellhead, they observed a clear acoustic signature of oil rising near the surface. The crew collected water samples to assist with the characterisation and validation of the acoustic signature.

Old survey data support new uses
The more people learn of the existence of geospatial data, the more unanticipated uses arise. One group of scientists learned that NOAA had multibeam survey data, collected during the 1990s, from the seafloor around the BP drilling site. NOAA used the bathymetric data, extending to the south and to the east of the BP drill site, to create a regional digital terrain model of the area, and that model is helping improve ocean circulation models.

Coastal planners have long anticipated the day when hydrographic survey data could help guide planning and restoration efforts after a major catastrophe. That day arrived earlier this summer, when the State of Louisiana asked for near-shore bathymetry, gathered earlier by single-beam soundings, to support projects protecting shores and wetlands from spill impacts.

In another novel use of traditional data, the US Coast Guard was able to use NOAA's coastline contour data depicting underwater surfaces to plan placement of spill containment booms. Bathymetric data was also used to plot specified geographical points to assist in water sampling activities.

Modelers stretch the imagination
What else does NOAA do with the contemporary and historical data? Just exploring the modeling developed to anticipate the extent and the effects of the oil could keep a coastal scientist occupied for decades.

Immediately, scientists from throughout NOAA and the US Navy combined modeling efforts to generate daily trajectories for both near-shore and offshore surface oil. Piling innovation on top of innovation – like adapting a model designed to track oyster larvae — the modeling team also began developing methods to produce three-dimensional trajectories. At the same time, NOAA scientists began looking beyond the three-day tactical forecast, working with weather experts, climate scientists, and regional river forecasting centres to develop long-range circulation forecasts that look out 40 days on the fate of the accumulated oil at the surface.

To be effective, today's emergency responders need to view spatial relationships. NOAA and the University of New Hampshire's Coastal Response Research Center developed the Environmental Response Management Application (ERMA), a web-based GIS that integrates oceanographic and environmental products into a common spatial format to determine the extent and effects of the spill, among other uses. GeoPlatform. gov/gulfresponse, the geospatial website for the oil response, is a valuable "one-stop shop," integrating the latest oil spill trajectory with fishery area closures, wildlife data and place-based Gulf Coast resources – such as pinpointed locations of oiled shoreline and current positions of deployed research ships – into one customisable interactive map.

Most recently, NOAA has used computer models to estimate the potential threats to US coastlines that might result if oil spilling from the Deepwater Horizon site continues until a relief well successfully stops the flow. Modelers point out that although it is impossible to predict precisely where surface oil will go in the coming months, it is possible to analyse where surface oil is most likely to go by (a) using historical wind and ocean current records; and (b) accounting for both natural processes of "weathering" and human intervention to recover and remove the oil.

Protecting the maritime economy
While much of the scientific response and recovery effort focuses, understandably, on wildlife and sensitive ecosystems, the US is acutely aware of potential challenges to the maritime transportation system, especially in these economically challenging times. Keeping mariners informed, and avoiding further complications in an already complicated maritime situation, NOAA produces several geospatial products specifically designed for safe and efficient navigation through the oil contaminated shipping areas.

To support safe and efficient maritime commerce, NOAA is producing nautical charting products that display the spill zone forecast based on the most recent projections. The charts depict the 48-hour forecast for oil location juxtaposed against the standard safety fairways that lead to port approaches.

These charts help ships avoid oil slicks, but mariners requested additional assistance. To avoid "traffic jams" among transiting ships, NOAA worked with the US Coast Guard and the US Navy to establish one of the alternative anchorage areas for vessels that need to undergo inspection and decontamination before entering ports. The pilots' association requested a magnetometer survey of the proposed alternate anchorage at the mouth of Southwest Pass, the primary deepdraft entrance to the Mississippi River to ensure that anchors would not rupture buried – and uncharted – pipelines.

The world gains a new understanding of geospatiality
As images of the spewing oil and far reaching plumes burn themselves into our human awareness, they are constant reminders that space, land, water, and life are intimately and exquisitely connected. To help the nation respond to and recover from this disaster, and to prevent another, geospatial experts from NOAA and other US federal agencies are providing an understanding of the physical and geospatial relationships that tie these systems together.