Tuesday, April 8, 2008

The Last 24 Hours of the Cruise

It’s Tuesday, and we’re scheduled to get in tomorrow morning to Ford Island and home. We could have made it back by late tonight, but apparently you can enter the harbor only during daylight hours, so we’re going a little slower than usual and should be hanging out at daybreak waiting our turn to enter the harbor. Today we had our farewell meeting of the scientific party, at which Kyle gave awards to Robyn as MVP for the cruise—with her sharp, young eyes, she spotted both the debris fragments we tagged with tracking buoys—and to Barbara, for most questions ever asked on a cruise! Barbara awarded Allan an honorary set of Big Eyes (made of paper towel rolls, a ship’s patch, and Andrea’s knitting yarn), signed by all who put in a shift, in recognition of his leadership and countless hours on the flying bridge every day and in the electronics lab every evening.

The CTD and small boat crews spent the day cleaning up the spaces we’ve used. The ship’s crew spent most of the day cleaning and preparing for our return to port. Each member of the Big Eyes crew put in a 2-hour shift, which felt astoundingly easy! Here I am, a seasoned ol’ salt on the Big Eyes, having just in the last day or so finally gotten the hang of how to scan efficiently (well, relatively so—I’m sure it’s an art that one improves at with many more than our 16 days).

The rest of the day looks like cleaning staterooms, starting to pack, getting some report-writing done, or making more headway on the marathon of The Wire, which has been the signature television event of the cruise. Most of us seem to have our heads firmly back on land already, with thoughts of ideal first foods or beverages, what we’ve missed most (significant others, pets), and what we’re dreading (dentist, taxes, all-day trainings, presentations). My head is right there with the others, looking forward to my household of husband, dogs, and cat, a carrot-celery-apple-ginger juice, and a nice grappa martini. Foods, not so much. One thing you can say for the SETTE, the stewards know what they’re doing. We were abundantly and well fed.

As the days passed on this cruise, I finally came around to the pleasures of sighting critters. Even though marine debris was the cruise’s focus, some participants are downright interested in sea life. Against my inclinations, I got to enjoy seeing the albatross hanging around and even got excited about shooting some photos of Laysan albatross with the monster camera, although this particular one may be taken by Allan once I gave it over to the pro.

Here are some black-footed albatross photos taken by Allan.

Earlier in the cruise, we saw sharks, scads of flying fish, dolphins, and some whales. Here’s a Risso’s dolphin, photo by Allan Ligon.

These Pacific white-sided dolphins are apparently unusual as far south as we saw them (about 35N). Amanda Cummins took this photo.

I’ll miss all the time to reflect on the ocean – when you’re observing, there’s a certain amount of chatting but lots of alone time too, to admire the surface of the water (at times it looks like molten metal, pahoehoe lava, Japanese watercolor waves, or Brazilian hillside favela rooftops), to ponder waves and wind, and to actually think about oceanography—circulation, productivity, Ekman transport.

This group of 19 scientists will scatter. I’ll see some of them on Oahu, though never so intensively, and others will scatter to neighbor islands or move off to other jobs or grad school. It’s been an interesting, challenging, and pleasurable cruise. In the words of Bugs Bunny, “Adios! Have a nice trip! Bon voyagee! Farewell to thee!”

Sunday, April 6, 2008

The UAS, at Last

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!

Reflections on Our Progress

We’re coming down to the final days of the guts of this cruise – after tomorrow or early Monday, we’ll be getting south of where the UAS is authorized to fly, and we’re already south of where we expect to find debris accumulations. After that, we’ll keep the Big Eyes crew going (just in case, and because we love it so), but otherwise we’ll just be steaming back to Oahu, which is going to take a few days.

I’m going to start with the good news. The marine debris folks even got on this cruise. That was huge! This cruise “belonged” to the Ecosystems and Oceanography Division of the NOAA Pacific Islands Fisheries Science Center, and they let the marine debris component piggyback on their cruise. Thank you! Evan and Hide were the oceanographers out here, and their part of the cruise went great. The CTD casts were a success, and with the convergence zone farther north than expected, we were even able to go back and cover another degree of latitude yesterday. The small boat crew helped out and the CTD operations were able to go 24 hours a day. That’s a big success, and that’s where this cruise, OES-08-02 started. (If you want to read a comprehensive and funny summary of the CTD operations, you can find it on the NOAA Sanctuaries mission page.)

So, where are we with the piggyback part—the marine debris component? What have we learned? How have we done on accomplishing our objectives? I could go cheat and look at the official cruise objectives, but since I’m not the chief scientist, that’s not what I’m held to. I think of myself as an observer, an interested but not yet invested partner, and someone who’s paying attention to the vibes of the scientific party.

If you Google in search of quotations about expectations, you’ll find a lot of cheerleadery stuff from sports figures and Mary Kay about self-fulfilling expectations, but I’d like to think Benjamin Disraeli got closer to this cruise’s outcomes: “What we anticipate seldom occurs, what we least expected generally happens.” I’ve talked to some of the other warm bodies, as we lovingly refer to ourselves, and to some of the Big Cheeses. Over all, a lot of us expected to find—and remove—more debris. The Big Eyes crew had a contingency for when the debris sightings came in so fast and furious we’d get behind on entering them into the computer. We even had a drill planned to train us—we never needed it. We never got to the part of the cruise that was going to bring back tons of debris and save the corals and monk seals. You better believe that’s a disappointment.

We thought going up to the convergence zone was a dead cert at this time of year. Apparently it wasn’t. I can think of a number of reasons. 1) It only apparently wasn’t. There’s plenty of debris, but we didn’t find it—for any number of reasons. The debris is patchy or the fog and high seas impeded our ability to spot it, or both. Our observing methods were in a testing, not operational mode, and the tests were not completed in time to move into operations. 2) It’s a La Niña year, and the convergence was weaker, so the amount of debris concentration was low this year. 3) Our understanding of how debris moves is incomplete. The Pichel et al (2007) paper gives a good idea of correlation between debris sightings and oceanographic parameters (sea surface temperature and chlorophyll content and gradient), but perhaps the year they flew, 2005, was an atypical year, or maybe 2008 was. (You can find the reference to that paper at the NOAA Marine Debris Program website.) 4) We need to work on our observing methods. Whether there was or wasn’t a lot of debris up there, we weren’t prepared to find it.

My mood? I’m a little let down, perhaps because my own expectations were too high. We all hoped that everything would work out just ideally, and maybe it could have. It’s dispiriting that not one component did, other than the CTDs that were the core of the cruise. We’ve tagged just 2 smallish pieces of debris, with 13 more satellite buoys on board. We’ve picked up less than 10 pounds of debris. The Big Eyes have been plagued by poor visibility, high seas, and lack of debris. The UAS flights have been few and not productive in terms of spotting debris.

In spite of the lack of resounding success, should we try this again? In the words of the Magic Eight Ball, my sources say yes. Not only that, but I say yes. Research is a funny thing. You don’t often get to publish the negative findings, but they’re data too. We’ve found at least one area of expected debris concentration that really didn’t live up to its reputation. When we’re getting giddy on the Big Eyes, we joke about that Texas-sized garbage patch, where it is, whether it exists, if we should plant a Texas flag on a buoy and call it good… Is it good news that we didn’t find debris? Well, it’s not bad news, but we do know that derelict fishing gear is making its way into the Northwestern Hawaiian Islands at a rate of over 50 metric tons per year. No one has estimated how much debris lands on the main islands, but we’ve all seen it and quite a few of us have hauled our share of it. We also identified a number of gaps in our understanding and places we need to hone our techniques.

What preparations should we make for the next try? Here’s my wish list.

- I’d like to have aircraft support; maybe have a NOAA, Coast Guard, or military airplane run up to the area of interest just before the ship arrives. They could observe quickly over a large area and point us to areas they see the most debris. That would save us a lot of time steaming back and forth.

- Additional ground-truthing of the satellite data the DELI (debris estimated likelihood index) maps rely on, like the shipboard measurements and CTD casts from this cruise, would be valuable. I’d also like a few more tests of the DELI maps with overflights.

- It would be ideal to go in an El Niño year, when convergence is strong and the zone is closer to Hawaii. Or at least not during another La Niña.

- If we continue to use shipboard observers, we should use the data from this cruise to develop some protocols, and then test them in a variety of sea and light conditions with abundant debris to sight. We’ve discussed doing a blind test comparing the sighting efficiency and distance covered by Big Eyes, hand-held binoculars, and the naked eye.

- The UAS testing did not always proceed smoothly. More work needs to be done on making the wing tougher, to take on the wind and sea conditions that are inherent in the convergence zone. The wing has not yet flown autonomously on this cruise, but in order to survey greater distances, it needs to be able to do so. Creating an algorithm to detect anomalies (like debris) in the video feed is a big challenge, particularly if there are a lot of whitecaps. We haven’t seen yet how that will work.

So I close this entry with hopes that we’ll come away from this cruise a lot better prepared to tackle this goal of at-sea detection and removal of marine debris. We’ve learned a lot, figured out some places we still need to learn more, and have gained a huge amount of on-the-water experience, even if it doesn’t feel so much like it tonight. And hey, there are still a few days left before we pull into Pearl Harbor on Wednesday. We could spot Texas after all!

Friday, April 4, 2008

About that Axe outside Your Stateroom Door

Funny thing about living on a ship. There are lots of weird things that you notice at first and gradually become normal. I thought about this because Amanda sent around an email list of ways you know you’re on a ship and not in a dormitory. One entry states “In the event of a fire, for your safety and convenience, gas masks are located in your room and outside the galley are racks of firefighting gear.” It’s true! Here’s our gas masks and some more elaborate versions from down the passageway. There’s much more outside the galley.

Then there’s the axe directly outside our stateroom door. It hasn’t yet featured in a dream, but I figure it’s only a matter of time. One would presume it’s for firefighting, but since most everything’s made of steel, I’m not quite sure what one would axe. Not a bunkmate, I hope, even to keep her from burning.

And the labels and warning signs. Many more things are labeled than you’d expect. The extra warning labels on this door to a stairway (aka ladder) make it clear that this is NOT the one for us. The door for general use just has the standard four labels: a descriptor, instructions, a single warning, and the direction.

This arcane device, on the door to the electronics lab area, looks like it’s from a 19th century chemistry lab. The instructions, largely unreadable when the device is in place and rather lengthy for reading in the event of an emergency, suggest it’s for grounding live surfaces, but my guess is it’s being stored pending delivery to a museum.

You probably know from movies and books (or even your own seagoing experience) that many ship parts have different names than their dry-land counterparts. Stairs are called ladders, fairly appropriately, given their steep gradient.

The mess is where we eat—apparently from some Latin meaning table or that which is put on the table. Left is port, right is starboard. Found this explanation online: The name is a very old one, derived from the Anglo-Saxon term Steorbord, or Steering-board. Ancient vessels were steered not by a rudder amidships, but by a long oar or Steering-board extended over the vessel's right side aft. This became known, in time, as the Steering-board side or starboard. The term “stern” also comes from steering, this time the Norse version. Much more interesting story for the toilet, which is called the head on a ship. Googled this one, although I’ve also read it in Tony Horwitz’s excellent book “Blue Latitudes,” which Robyn read on this cruise. “Head” in a nautical sense referring to the bow or fore part of a ship dates to 1485. The ship's toilet was typically placed at the head of the ship near the base of the bowsprit, where splashing water served to naturally clean the toilet area. In our toilet area, the cleaning methods fall to the four users.

Finally, a source of endless fascination in Kelly’s and my otherwise faultless stateroom (that’s sea for bedroom) is the desk lamp. It was clearly designed and installed by a sadist. Note the sharp edges. Note the handy location of said edges, directly adjacent to where one’s head is while working at the desk. Swivel in chair to say hello to someone and presto! A new knot on your head. After 12 days at sea, I still catch it frequently. Actually, I whack my head on metal parts everywhere on the ship pretty regularly—not sure why hard hats aren’t required at all times.

Thursday, April 3, 2008

Oceanography (Part II), with Debris Musings

If you read the last oceanography post and are back for the stunning finale, I just have this to say to you: Are you kidding me? No, I mean, thanks. I hope I’m making sense and not telling a pack of lies. If you happen to be an oceanographer, please let me know how to fix this. I’ve been thinking so hard by brain’s about to pop, and I really do want to understand it and be able to communicate it. Thanks in advance for your help.

The Transition (and convergent) Zone: As you head north from the subtropical gyre (characterized by chlorophyll under 0.15 mg/m3) to the subarctic gyre (chlorophyll over 0.25 mg/m3), you go through a transition zone between them. The transition zone moves by roughly 1000 kilometers north and south throughout the year, from about 30-35 to about 40-45 degrees north. In the summer months, it moves to the north (as the sun heats up the water). Right now, at the end of winter, it should be near its farthest south position, or maybe heading north already. There’s a chlorophyll front at the boundary between the two gyres, which scientists have called about 0.2 mg/m3 of chlorophyll. This generally occurs near the 18 degrees C isotherm (line of temperature). (Exception to the “generally” rule: on this cruise, we’ve actually been seeing the chlorophyll front to the north of the 18 degree isotherm.) The chlorophyll front is generally a convergent zone as well. The easterly trade winds we experience in Hawaii result in surface water moving north (a rule of thumb is that the Coriolis effect makes the top ~100 meters of water move 90 degrees to the right of the wind direction, at least in the Northern Hemisphere). To the north, westerly winds result in surface water moving south. Where these waters come together, that’s convergence. A number of scientific papers have hypothesized and in some cases seen that marine debris is concentrated by this convergence.

We’re comparing the DELI (debris estimated likelihood index) maps, which have been prepared based on satellite-derived data on chlorophyll, sea surface temperature, and wind stress, with on-the-ground measurements of chlorophyll and sea surface temperature, as well as our debris sightings.

If I haven’t lost you yet, congratulations! You’ve pretty much reached the end of my understanding (or ignorance!) of oceanography. Two more thoughts. Variations from year to year can make a very big difference. In El Nino years, the chlorophyll front and the associated convergence move much further southward. A number of papers have been published showing a correlation between El Nino years and increased marine debris deposition or seal entanglements in the Northwestern Hawaiian Islands. Conversely, in La Nina years, the convergence is likely weaker and the convergence zone doesn’t move as far south. We seem to be in a La Nina right now, and we had to go quite a lot farther north than we’d anticipated to find the chlorophyll front. We weren’t quite as successful (so far!) in finding large concentrations of debris.

OK, that’s one thought. The other? It’s a biiiiggg ocean. Let’s say a DELI map shows one pixel covering about 6 square kilometers. Our ship is 68.3 m long by 13.1 m wide. That makes us 895 m2. That means 7,000 ships the size of the SETTE could fit inside just one of the pixels on a DELI map. The map I’m looking at shows moderately high likelihood of encountering debris across 2 degrees latitude by 13 degrees longitude, roughly 228,000 km2, or about 40,000 pixels. If the DELI map (which is just giving us an estimate anyway) is off by a few pixels because the data are a few days old, we can be driving almost blind. That’s our challenge. By improving our understanding of the oceanography of this transition zone between the two gyres, by improving our protocols to observe debris from ships, by testing and improving the technology to use other observing platforms, like the UAS: these are the ways this cruise has helped get us a bit closer to our goal of finding and removing the debris before it gets into sensitive areas like the Northwestern Hawaiian Islands.

Another Day, Another Tracking Buoy Deployed

Say, I just learned that you can follow us online at http://shiptracker.noaa.gov/. You just click to enter NOAA’s Ship Tracker, then select the ship SE (Oscar Elton Sette) and let it show “current cruise.” It’ll show you where we’ve been, where we are, and which way we’re headed. I wish I’d known about this from the beginning! Here’s an image from earlier today.

We were in for more crazy pitching seas overnight. We reached the northernmost point of our cruise, and the coldest temperature (10 degrees C, which is about 50F—plenty cold for locals). We stopped again for CTD casts four times today. There was a whole lotta nothing spotted by the observers for hours. Then Robyn spotted it—she was completely baffled by what she saw through the Big Eyes. “Is it two flags?” Sounded weird enough to investigate, so we asked the bridge to drive the ship closer to investigate. Still looked interesting, though we didn’t get very close for fear of fouling the ship’s screws on any line that might be attached to the flagged buoy. Here’s Doug getting the SAFE boat ready to launch. They use a winch to pick it up and drop it down into the water.

Kyle, Frank, and Lester went out and took what felt like forever to investigate and attach a tracking buoy to the buoy. It turned out to be an old and very heavily fouled buoy with a roughly 4-foot flagpole and two orange pennants on it. Not the enormous net bundle we’d hoped to tag, but definitely better than going home with all our trackers!

Robyn is now officially the Big Eyes rock star. She’s generally very modest about it but agreed to pose for the paparazzi just this once.

The weather improved by the hour today. By the last shift of the day, gloves were options. We’re looking for even milder weather tomorrow, perfect for Big Eyes, UAS flights, and small boat operations. Wish us luck!

In Which I Attempt to Demonstrate an Understanding of Oceanography (Part I)

You may not have noticed that I’ve stayed an arm’s length from discussing how oceanic circulation in the Pacific affects the movement and accumulation of marine debris. Believe me, it’s been intentional. We hear a lot of terms bandied about, and as someone whose sole graduate course in physical oceanography happened in roughly 1981, I’m no expert. However, I’ve been hanging around with some of these oceanographers for over a week, and I’m ready to tackle it.

First some basics. The sun warming the air, combined with the earth’s rotation, creates general wind patterns. Winds, again combined with the earth’s rotation, generally drive surface currents. So in the northern hemisphere, we have two major gyres, or circular circulation patterns. The first (if you’re from Hawaii, that is) is the clockwise North Pacific Subtropical Gyre; it’s made up of the Kuroshio Current, which flows north past Japan on the western side of the basin, the North Pacific Drift, which flows eastward along the northern part of the basin, the California Current, which flows southward past—you guessed it—California, and the Pacific Equatorial Current, which flows westward just north of the equator. To the north, there’s a smaller, counterclockwise pattern called the North Pacific Subarctic Gyre. OK, that’s the basic circulation pattern.

Now for a tiny bit of biology. You know how plants have chlorophyll—the green pigment? Well, in the ocean they do too. And chlorophyll is one of our big indicators of the boundary between the two gyres. Here’s why. The North Pacific Subtropical Gyre is closer to the equator, so the surface water is warm. Farther north, in the subarctic gyre, the water is colder at the surface (and on this cruise, we’ve experienced that cold water and the weather it creates!). Deeper water, no matter where you are, is cold and generally has lots of nutrients that allow water to be productive. We call the subtropical gyre “oligotrophic,” which means there’s relatively little productivity. One of the reasons? Stratification, by which I mean layering. The surface layer is warm, the deeper waters are cold, and not much mixing between the two happens between the warm and cold water, across the thermocline. By contrast, the waters to the north, in the subarctic gyre, are cold and rich in nutrients. That richness in nutrients is due to good mixing – when the surface water is cold, there’s little impediment to mixing of nutrient-rich (and cold) bottom water. As a result, the northern water mass sustains all kinds of life, particularly phytoplankton (tiny floating plants), which contain chlorophyll, the green stuff of plant life. Very productive waters have more chlorophyll and look a little greener. Those beautiful blue waters offshore of Hawaii don’t have much chlorophyll. So: subtropical gyre = warm, stratified water, low nutrients, low chlorophyll; subarctic gyre = cold, well-mixed water, higher nutrients, higher chlorophyll. Got it? OK, now take a break. I intend to—maybe some of that German chocolate cake from dinner is still down in the mess…