I know I promised to get back to where the UAS, the unmanned aerial system, fits in to the overall at-sea detection and removal scheme—and I haven’t yet. Well, it’s high time. First of all, let me direct you once more to the UAS crew’s blog, which is in the “For More Information” box over to the right. They’re really the ones to tell about it, but since you’re here, I’ll give my version.
This whole UAS concept grew out of the GhostNet project, which began around 2001 to explore the use of remote sensing, from satellites and aircraft, to map marine debris in the North Pacific Ocean. It was a partnership of ATI, Inc., and part of NOAA Satellites, Fisheries, and Research. The satellite imagery was used to map the oceanographic conditions that would concentrate debris, and the airborne remote sensing would spot the debris. An additional component of the project involved creating tracking buoys that could be attached to debris. These buoys send a signal with their location every 12 hours to a satellite that the GhostNet team tracks. You’re familiar with each of these components from this cruise – the use of NOAA and NASA satellite imagery by NOAA Fisheries’ CoastWatch to create the DELI (debris estimated likelihood index) maps, the airborne component (the UAS), and the tracking buoys, two of which we’ve deployed on debris on this cruise. (Don’t forget, you can track their location at http://www.atiak.com/buoy_maps/; pull down to view 15FXZ—the other buoy we deployed isn’t up there yet, but it will be the one that starts on 4/3/08.)
In 2005, the GhostNet team flew a NOAA P3 aircraft around the convergence zone, as located by using satellite data on chlorophyll and sea surface temperature. They used on-board observers to locate debris (nets, floats, lines, buoys, etc.), and they found a good correlation between the oceanographic parameters and the debris sightings. While that flight used human eyes, there is also interest in developing an image-based detection method, which is basically a video feed (which might measure visible light or infrared radiation) coupled with a software program that detects anomalies. When an anomaly (say, a net) is detected, that information is saved, either by saving the video feed a few seconds before and after the anomaly or by triggering another camera to take a high-resolution photograph. That way we can go back and take a closer look at the images and, if it looks like debris, can go investigate further.
Of course, when you’re in an airplane, you can just map what’s there at that time. And since debris tends to move, that map may not be useful for very long. That’s where the UAS comes in. By launching from a ship an unmanned aircraft that has some of these same sensors onboard, we think we’ll be able to combine the detection and removal of debris. As you’ve learned, we’re not there yet, but we have come a long way on this cruise. Evan told me that it’s not a piece of cake to find the biological transition zone—he felt we were pretty lucky finding it on this cruise. Having the DELI maps and an aircraft survey just prior to a cruise would make our efforts much more efficient. The UAS has proven itself able to be launched from a ship, fly in 20+ knot winds, and be recovered at sea. We never really had the opportunity to test the autonomous flight or the anomaly detection software, so more work has to go into those aspects. But the UAS seems to be the part that will bring the detection and removal components together onto the same expedition, by expanding our ability to see debris from the air throughout a cruise, not just when long-range airplanes are available.
I hope we’ll be able to see progress continue on the UAS development and put it into operation soon. There are a lot of folks on this ship itching to get out there and pick up the debris—we just need to find it. Now, I need to post this and turn off the computer or I’ll lose my dinner – the ship is pitching like mad!