In this monthly feature, we span the globe to examine Our Changing Landscape with time series imagery stacks of medium resolution RapidEye satellite data. The RapidEye archive dates back to late 2008 and already contains more than 3 billion square kilometers of data. This month, we travel to the Gulf of Mexico and look at changes in the surface oil slick created by the Deepwater Horizon explosion as it changed from day to day.
The RapidEye Constellation
RapidEye is a constellation of five 5-meter medium resolution satellites each offering five spectral bands of information. The RapidEye constellation offers a daily revisit time to every location on the planet with a huge footprint that is 77-km wide. The data is priced competitively with a base price of $1.28 per square kilometer for all five spectral bands – academics receive a discount on this price. RapidEye adds a fifth band, the red edge, to the ‘traditional’ multispectral set of blue, green, red and near-infrared (NIR). The additional spectral data available in the red edge band allows users to extract more useful land ‘information’ than can be from traditional 4-band imagery sources. When RapidEye imagery is ordered as a Level 3A Orthorectified product, images from multiple dates are extremely well registered, making it the ideal data source for Our Changing Landscape.
The Deepwater Horizon Oil Slick
On April 20, 2010 at 9:45 PM Central Daylight Time, an explosion deep on the floor of the Gulf of Mexico below the Deepwater Horizon kicked off a highly televised and scrutinized environmental disaster that lasted nearly 4 months until July 15th when the ruptured exploratory well was temporarily capped. During this time, the US government estimates that 4.9 million barrels of oil were discharged into the Gulf and of those 1.065 million barrels were recovered or burned with 1.07 million gallons of dispersants applied to clean up the spill. As the events surrounding the explosion of the Deepwater Horizon are likely ‘old news’ to many of our readers, the focus of this short piece is the variability in geographic extent of the surface oil slick which changed dramatically even over short time periods. Unlike terrestrial oil spills where flows can be modeled with some degree of certainty based on local topographic conditions, land cover types, soil chemistry, etc., the extents of an oil spill in open water is unpredictable given ever-changing wind and water currents as well as chemical decomposition.
The series of images that follow this paragraph were collected during the four months in 2010 that the Deepwater Horizon gushed oil into the Gulf; and several of them were even obtained within several days or less of each other. This unique RapidEye dataset shows dramatic changes in the surface extent of the oil slick over an area covering 25 km by 25 km, or 625 square kilometers, just to the west of the Deepwater Horizon. When you watch the animation, it’s hard not to imagine the enormity and complexity of the challenges that faced those deemed with the task to contain and remediate the oil and other compounds that seeped up from the floor of the Gulf.
If you would like to find out more about using RapidEye for your academic studies, engineering projects or any landscape analysis, let us know at [email protected] or (303) 993-3863.