Ocean Garbage Research

Teledyne and The German Aerospace Center are working together to make a difference in the clean-up of the world’s oceans. One of the most significant threats impacting oceans is marine plastic debris. Marine plastics can come from derelict fishing gear, ghost nets, trash that flows from rivers into the oceans, and numerous other sources. Marine life can become entangled in and, in some cases, ingest plastic refuse. This debris can prevent sunlight penetration into the ocean and impact plant and algae life-cycles. Large aggregate points for trash and pollution form around natural circulation points in the ocean currents called “gyres”. There are five major oceanic gyres and numerous smaller gyres that accumulate pollution. The major river systems, like the Ganges, Amazon, and Citarum, also contribute to the marine debris crisis.

These fields of debris, consisting largely of plastics, have become the focus of many organizations concerned with the health of the oceans. Yet, studying marine plastics with satellite and airborne imagery is a challenge due to the remoteness of these sites.

The ocean is a highly dynamic environment, which means the floating debris fields are constantly moving, and the sensitivity of traditional satellite sensors are not designed to distinguish these materials. It is now possible to collect imagery that reveals the composition and density of these debris fields. With the use of the DLR Earth Sensing ​Imaging Spectrometer (DESIS) sensor aboard the Teledyne Multi-User System for Earth Sensing (MUSES) pointing platform on the International Space Station (ISS), coupled with the ocean current model General NOAA Operational Modeling Environment (GNOME), investigators will be able to both predict the location of and characterize these collection points. This will allow us to study the extent, monitor changes, and plan mitigation actions for the accumulated debris in these areas.

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The DESIS sensor is a hyperspectral instrument, collecting reflected light in very narrow bands (~2.55nm). These narrow bands can be more sensitive to plastic debris signatures. Plastic is made of hydrocarbons, and even very small plastic particles can have an impact on the spectral signature from a 30x30-meter patch of water. Initial efforts to collect DESIS data over the center of the Eastern Pacific Garbage patch revealed distinctly different signatures from the water and clouds, which were determined to be rafts of plastic debris. Teledyne is collaborating with NOAA for their clean-up missions scheduled in 2020 to collect additional data from DESIS to support NOAA’s mitigation efforts.

The orbit of the ISS provides more opportunities to collect imagery over equatorial zones as opposed to satellites that orbit around the earth’s poles. Not only is the DESIS sensor well suited to detect debris, but it also has the capability to capture images of the ocean in areas that are notoriously cloudy. Plastic debris is an imminent threat, silently invading our oceans and, ultimately, impacting the food sources provided by our oceans.

Because the debris is so widespread, understanding the extent, amount, and impact must be evaluated from space. DESIS aboard the MUSES platform on the ISS provides a beachhead to design studies to assess this enormous problem.
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by Amanda O'Connor​​​

Oil Spill Research

The DLR Earth Sensing Imaging Spectrometer (DESIS-30) is the first commercially available hyperspectral remote sensing camera in Low Earth Orbit (LEO).

Coverage of the spectral range from 400 to 1000 nm is acquired in 2.55 nm bins (235 bands), with a ground sampling distance of ~30 m. DESIS arrived on the International Space Station (ISS) on June 29th, and collected its first image on October 2, 2018. Testing of sensor calibration and data dissemination processes are ongoing and should be complete in early August 2019. As the pioneer system on Teledyne Brown Engineering’s (TBE) Multi User System for Earth Sensing (MUSES) platform on the ISS, DESIS has collected over 4.5 million square kilometers of hyperspectral data. MUSES provides directional pointing and onboard storage for the imager. The data from DESIS is then downlinked by the MUSES Operations Team at TBE’s Operations Center in Huntsville, AL and delivered to dedicated cloud processing and storage infrastructure for customer delivery and archiving.

Now that information is being delivered from the instrument, there are many unique applications for the DESIS data. There are numerous marine hazards that the imager can monitor and assist with disaster recovery. For instance, the National Oceanic and Atmospheric Administration (NOAA) maintains an incident archive of hazards being monitored. This archive includes thousands of different types of marine concerns such as oil spills/slicks, sunken ships leaking fuel or oil, large MUSES' HOSTED PAYLOAD: DESIS sea mammal carcasses, plastic rafts, fishing gear, gas releases, and debris. The ISS orbit provides increased opportunities for collecting data over tropical ocean zones, which are often obscured by clouds. This enhanced tropical, temporal coverage provides organizations like NOAA and the US Coast Guard more opportunities to detect, chart, monitor and mitigate oceanic hazards.

Last February, DESIS collected two scenes just southeast of the mouth of the Mississippi River, an area of considerable ship traffic as well as offshore drilling activities. In September of 2004 Taylor Energy’s Mississippi Canyon 20 (MC20) oil platform collapsed in this area. Since that time, crude oil has been leaking from the well site. This site has been monitored by satellite imagery, but the latest information collected has shown this site continues to discharge up to 4,500 gallons a day, much higher than initial estimates of 3-4 gallons per day.

Following conversations with the NOAA Hazard Mapping team, DESIS imagery was ordered and processed to confirm observation of the MC20 slick. Imagery from these scenes showed a distinctive sheen associated with surface oil. Oil on the surface often is composed of foamy bubbles from water agitation, which reflects strongly in the infrared. The color infrared composite below shows several reddish streaks. NOAA analysts believe these are from the Taylor Energy leak. TBE is in the process of delivering these images to NOAA to provide absolute confirmation.

Why Hyperspectral and Why DESIS

DESIS can be a valuable tool for mapping ocean hazards. The first is the ISS orbit which provides more opportunities for mid latitude coverage, this increased temporal access is especially important in frequently cloudy areas like the Gulf of Mexico. The second is the narrow bands allow for more precise mapping of hydrocarbons. In the spectral plot below, the oil has a distinct peak near 725nm and 950nm that the surrounding water does not have.

Using spectral processing techniques, it is easy to map the slick relative to the water. By searching for pixels that have a higher reflectance in the 725nm and 950nm bands relative to other pixels, a vector can be created that shows the slick extents at the date of February 2nd 2019. Ongoing imaging can show how the slick changes, and combined with sonar data, current modeling and other inputs, a volume of oil can be estimated.

              

 

NOAA and other international organizations monitor slicks like these, whether they are manmade or natural. By using a known location/origin or by tasking DESIS where ocean current models predict hazards like these may occur we can provide a better situational assessment. The imagery can provide new options for mitigation and additional understanding about how they may impact beaches and marine life. DESIS also provides a global tool for monitoring and assessing marine hazards and pollution whereas most other hyperspectral imaging systems are aerial and have a limited range, making oceanic hyperspectral study difficult if not impossible. DESIS can be used to create a spectral library of different kinds of oil in multiple water types, collect plastics signatures, determine different thicknesses of oil, and collect other hazard spectral characteristics. With a library such as this, one can automatically search for signatures of these hazards and the prospect of monitoring the world’s oceans becomes approachable verses an impossibility.

Sensors like DESIS, a flexible pointing platform like MUSES and methods like these are the ground breakers for next generation sensors that can provide hyperspectral coverage at different spatial, spectral and temporal resolutions. By working with partners like the DLR, NASA, NOAA, the Alabama Remote Sensing Consortium, we can begin to ask questions of hyperspectral data we never thought possible. DESIS aboard MUSES are the pathfinders for hyperspectral application discovery and Teledyne is once again showing itself to be “Everywhere you Look”.

by Amanda O'Connor​​