Melt pond evolution and glacier acceleration:
An investigation into the cause of fast glacial flow in
East Greenland

This Project is supported in part by a generous grant from the
Dan and Betty Churchill Exploration Fund

Gordon Hamilton and Leigh Stearns

June 22, 2006 to July 6, 2006

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The main goal of our Helheim 2006 project is to understand the mechanisms bywhich glacial “ice”quakesoccur, and their relation to glaciological processes. Information about the projectlogistics and team members can be found at Lamont-Doherty Earth Observatory, Columbia University andour own Project Page. Basically, we are setting up a network of GPS stations acrossthe glacier to determine ice flow patterns in relation to ice quake events (andbecause ice flow patterns are interesting and glaciologically relevant). Icequakes (also called glacial earthquakes) have been recorded around Helheim glacierduring the summer season for the past XX years. In order to try to ‘capture’ oneof these events in the GPS data, we are aiming to leave the receivers on theice for ~2-3 months this summer.

Three field trips are organized for the summer 2006 season. The first trip (June 24 – July 2) is the deployment phase, where we put all 20 (hopefully) GPS receivers on the surface of Helheim Glacier. Because this is a fast moving glacier (~11 km/yr at the calving front), and the GPS receivers are expensive, a mid-campaign trip is planned for July 21- July 27 to download available data and insure the stability of the equipment. It is possible that the receivers will no longer be in a ‘safe’ location and we will have to pull them out before they fall in a crevasse. The third trip is scheduled for late August and is when we will pull out all of the instruments. We hope to do this BEFORE any snow falls so that crevasses are easy to see.

TRIP 1: GPS deployment June 27, 2006 Tasiilaq, Greenland
We are spending the week at Tasiilaq, which is the closest village to Helheim Glacier. We have chartered a Bell 222 helicopter to transport us (and our gear) to and from the glacier, ~100 km to the northwest. Unfortunately helicopter time is REALLY expensive, so we have to be organized in our planning and efficient in our site installation. However, Helheim Glacier is extremely crevasses (see pictures) and is therefore very hard to land a large helicopter on. A good portion of our time is spent searching for safe places to land and checking to make sure that the ice is sturdy to walk on.
Gordon, Andreas Ahlstrom (from GEUS) and I headed to Helheim Glacier this afternoon to deploy two GPS stations at the snout (or front) of the glacier, while colleagues from the Danish National Space Center (Abbas Khan and Lars Stenseng) set up a base station on an adjacent nunatak. Our plan is to leave two receivers at the front of the glacier for 2-4 days, to get a sense of the glacier velocity and any influence the tide may have on the ice motion. Since we left the equipment so close to the calving front (where the glacier calves off icebergs into the fjord), it is important that we retrieve the GPS receivers within a few days or they will most certainly fall into the fjord! The installation was successful and the glacier, as always, was stunning.

June 28, 2006 Tasiilaq, Greenland
We set up six stations this afternoon, and were getting very efficient at it, averaging ~ 7 minutes at a site. Once we get to a site, we have to drill two 3-meter holes, to put our poles in, set up the GPS equipment and solar panels, and mark the site with lots of flags so that we can find it again. In this part of Helheim Glacier, we expect 1-1.5 meters of surface melt throughout the summer, which is why we have to drill our holes so deep. Shorter poles would just melt out in a matter of weeks.

June 30, 2006 Tasiilaq, Greenland
We installed 16 permanent GPS stations on the ice (see map), in addition to the two temporary stations that are near the calving front. We have three reference stations on nearby bedrock ridges, which is necessary in order to process the data and determine how fast the glacier is moving. Tomorrow we will pick up the snout (front) stations and head home.

TRIP 2: DATA DOWNLOAD and SITE FIXING! [Pedro Elosequi, Gordon Hamilton, Meredith Nettles, Leigh Stearns]

July 22, 2006 Tasiilaq, Greenland
Gordon and I arrived traveled straight from Orono to Boston, to Reykjavik, to Kulusuk, to Tasiilaq today (I suppose we started traveling yesterday)! We got to Tasiilaq at 10am and rested for a few hours before flying to the glacier at 2pm. Together with Meredith, we installed a tide gauge at an inlet near Helheim Glacier. We are interested in the relationship between tidal fluctuations and ice velocity – the ice velocity of many tidewater glaciers will vary 2-4% due to the tide. We also installed two GPS stations on the snout (front) of Helheim Glacier to measure this effect.

July 24, 2006
Unfortunately, many of our solar panels were not producing enough charge to run our GPS receivers, so we spent most of the day adjusting the panel setup to maximize the charge. This meant scavenging through the town dump, taking apart wood pallets, and building ‘solar panel frames’. The wind can be very strong (and the solar panels are very floppy) so we had to devise a way to keep the panels flat and open!

July 25, 2006
Pedro, Meredith, Gordon and I visited the each of the sites today. Depending on the state of the site, we redrilled holes, retied solar panels, swapped out receivers and downloaded data. We got to be pretty efficient at fixing the sites and it was always interesting to see what state they were in! At a few sites, crevasses had opened up BETWEEN our receiver and antenna. Luckily we found and fixed all the sites.

TRIP 3: SITE CLEAN-UP [Gordon Hamilton, Morten Langer, Meredith Nettles, Abbas Kahn, Leigh Stearns]

August 25, 2006 Tasiilaq, Greenland
I suppose this was supposed to be a site clean-up trip, but all we did today was install NEW stations. We got very interesting data from our first set up snout GPS stations, so today we set up four more – all within 3 km of the calving front. We also revisited one of the reference sites (on bedrock). It’s a good thing we have 3 reference sites, because the wind had ripped the solar panel completely off its backing.
The calving front had retreated a bit since our first trip. It seemed like there were even fewer decent landing spots for an enormous Bell 222 helicopter. There were more ice spires and fewer ice platforms. With much hunting, we managed to find four good sites though.

August 26, 2006 Tasiilaq, Greenland
Morten and Abbas arrived in the afternoon and we flew to Helheim shortly afterwards. We ended up retrieving 6 stations before the weather got too bad to fly in. They were particularly difficult sites to access, since the crevasses had grown since our previous visit. Crevasses divided our landing spot from our equipment at more than one site, and took a lot of time and energy to navigate. Fortunately we retrieved everything safely and efficiently!
The heliport had a BBQ when we got back from the field, and they were nice enough to invite us along. I got to try grilled whale, which was actually pretty tasty.

August 27, 2006 Tasiilaq, Greenland
We had an easy Sunday today because the pilot had the day off. So, we spent the day cleaning up gear, downloading the GPS receivers that we collected on Day 2, and planning for tomorrow.

August 28, 2006 Tasiilaq, Greenland Morten, Meredith, Gordon and I collected the rest of the sites today while Abbas worked with the reference GPS site (on the adjacent ridge). We were all very excited because we retrieved ALL of the units except 3 (and the snout stations). There was only one site that we couldn’t land at with the Bell 222 because the “crevasse-free” platform had become significantly smaller in the past month.
We saw the northern lights tonight. They were phenomenal but impossible to capture with a camera.

August 29, 2006 Tasiilaq, Greenland
Gordon and I retrieved the final GPS stations in the small and snazzy A-Star helicopter. It was much easier to land and work with. The only downfall was that its cabin was pretty small, but since we only had 4 sites to retrieve, it was ok. We got back to Tasiilaq at 12:30 and caught a 1pm ride to Kulusuk and are heading back home.

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