Greetings from Newfoundland and Labrador! We are back on the CCGS Amundsen and are currently located between the Flemish Pass and the southern Labrador Sea. The ship is steaming north into the sea ice, or what is left of it.
Before I lay out the background on this trip and what we’ve been up to for the past 10 days, I should finish up the final week or two of the Svalbard trip. The skies continued to lighten while we were there, but unfortunately the sun failed to show through the cloud on the day of the Sun Festival. This is when the entire community comes out to the old hospital steps and waits for the first moment when the sun could possible shine above the mountains towering over the town of Longyearbyen. There is a 15 year streak of this occurring, but no one seemed discouraged at the gathering afterwards where we all dug into ‘sun’ donuts and waffles with caramel (!) cheese. The last weeks were also filled with skis up glaciers, an epic snowmobile expedition to a tidewater glacier named Paulabreen, a final exam and a short holiday in Oslo.
Then it was back to Ottawa to prepare (with haste) for the field campaign which Derek (my graduate studies supervisor) and I are on now. Though we knew that this trip was in the works since December, nothing had been finalized before I left for Svalbard – which meant that none of our preparations had been either. The three week turn-around between Svalbard and Quebec City for the Amundsen’s mobilization worked out in the end and a Dodge Caravan filled with aluminum plates, metal storage cases, 10 ft metal beams and 150 kg of pea gravel (you’ll see…) wheeled into the Coast Guard docks in Quebec City on April 12. We spent the following days setting up our lab, and most importantly, setting up one of the major components of our iceberg mapping experiment.
The reason d’etre of Derek and I for these weeks is to test methods for mapping the above-water portions (or ‘sails’) of icebergs. Though our lab group mainly focuses on ice islands further north in the Canadian Arctic, this Amundsen cruise (dedicated to iceberg and sea ice study) was a perfect opportunity for us to develop these methods for future use on ice islands.
These methods include photogrammetry and laser scanning surveys of the iceberg’s sails. Photogrammetry (and specifically something called Structure from Motion) is essentially conducted with a series of overlapping aerial photos which sophisticated software stitches together to ultimately produce a 3D model of a target. However, a drifting target of ice makes this difficult. Distinct features can be hard to come by on a chunk of ice and we have to account for the movement which the iceberg underwent during the surveying. So, before we can do the photo-survey helicopter flight we have to use the helicopter for transport to the iceberg and deploy a series of ground control points (these are man-made features for the software to identify) and GPS units (for post-correction of the iceberg drift, and to give scale to the final model).
The GPS placement is also important for the second method that we are testing – the laser scanning. This is done from the small barge which can be deployed from the Amundsen and was the method which which Derek and I had the least experience. We had some help in the set-up and calibration of the instruments while in Quebec City, where we strapped the set-up (those aluminum plates and beams) and the laser scanner, two GPS units and something called an inertial monitoring unit (to account for the barge movement) on-top of the Dodge and drove around the Coast Guard docks. We certainly had everyone’s full attention with our get-up, and after some modifications to mount the survey-frame safely on the barge’s cabin, we were set to go. The plan is to circumnavigate an iceberg three times with the laser scanner to produce three separate models of the sail. An added plus is that there is another group on board with the equipment (a multibeam sonar) to map the underwater portion of the icebergs, coincident with our work. So we should have three models of an entire iceberg by the end of the trip.
Three surveys are also to be completed during the photo surveying. The idea of both the laser scanning and photogrammetry is to compare the three models produced by the single method to assess how precisely each method can produce a model. The variability between models can then be used to determine what magnitude of deterioration you could theoretically detect if you were able to survey a target over a longer period of time.
A lot hinges on the use of the helicopter. The GPS placement is necessary to account for drift during laser scanning as well as photo surveying. And of course this is always complicated by flying conditions. During our first big day of surveying yesterday we had to work in bursts during brief windows of adequate flying conditions. I have never had to consider the proper conditions for the barge in previous years but am now learning that there are a number of considerations on this front as well. It cannot be deployed when the sea ice concentration is too high, or when the sea state is too great. Getting back on the barge reminds me of my first trip in 2011 on the ship when I helped the team working the AUV (autonomous underwater vehicle) from the barge. My first day out I got so sea sick that sprawled out in the small red shelter that they have onboard. Remembering this makes me understand at least one of the reasons for only operating the little vessel such as this when the waves and swell are of a permissible size!
The sea ice concentration issue came up yesterday during our first day of surveying. However, we adjusted – we still did the laser scanning, just with the barge still on-board the Amundsen’s deck! It was an interesting day, and quintessentially Amundsen. We planned our perfect survey day weeks ago. This would be 10 hours of activities in a pre-determined sequence, but we all know by now that those plans go out the window in no time on this ship and you do what you can to adjust. It is really nice to report that we already have solid data from yesterday’s work – GPS units were put out and three surveys from both the helicopter, and docked barge, were conducted.
The final element of our project is oceanographic data collection for a collaborator’s research on iceberg drift modeling. This does hinge on getting the barge in the water, which we hope to do today. First though, we have to locate an iceberg that was identified on some satellite imagery yesterday. This is proving difficult in 15 m visibility!
A major reason why yesterday was such a success is that Derek and I were given 3 opportunities to test our external camera mount (‘the Pod’) on the helicopter, and the wireless control for operating the camera, in the first few days of the trip. We also got out on the barge and tested the laser scanning on the Amundsen itself. This really helped our confidence and allowed us to hone our methods for the few days of true surveying which we are given. One modification included the replacement of plexi-glass like material for The Pod, which had me scouring the industrial section of St. John’s while we were in-port.
I think it is safe to leave it at that for now. Cross your fingers for clear skis and calm seas (seems like we just keep asking for more and more!).
Next up: pictures from yesterday! I just need to raid another computer’s files for those!