Enter the Deep Field

January 21, 2013

Hello from Pine Island Glacier! I am currently sitting at PIG main camp waiting for a Herc to pick us up and fly us back to McMurdo. It is in the air right now, so looks like I could be back in civilization tonight!

The last two weeks in the field have been hectic and exhausting but all in all it’s been an awesome experience. Back on Monday the 7^th we left McMurdo after a few days of waiting. The experience of waiting for a flight to leave McMurdo is best summarized by the phrase “hurry up and wait.” After driving out to the airfield and waiting in a little room for four hours with no info at all (other than rumours being circulated amongst ourselves about when the Herc would leave), a lady rushed into the room in a panic telling us we had to get into vans as quickly as possible to get to the plane. The runway was so mushy that the vans couldn’t drive through the snow, so instead they drove them sideways onto a “magic carpet”, and dragged us out to the runway using a much bigger vehicle. The runway has been unusually soft this season, which has caused some serious logistical problems in McMurdo.

We first took a three hour flight to WAIS divide (West Antarctic Ice Sheet Divide), which is the watershed that divides the West Antarctic Ice Sheet into two drainage basins. They have a 50 person camp there, whose main purpose is to drill a 3.5km ice core which lets scientists look back into the past by studying the different layers of ice that have accumulated over time. The ice at the bottom of the core is 62,000 years old! We stopped for a quick dinner at WAIS camp and then hopped on a twin otter heading to PIG Main camp. The Twin Otter flight was about two hours and I had some amazing views of the ice sheet out the window. The interior of West Antarctica is essentially one massive flat plain of white ice, stretching as far as you can see. I might as well have been on another planet.

PIG Main had 26 people in camp the night we got in. Despite being the most remote field camp in the US Antarctic Program, PIG Main had unbelievably good food. Thanks to Joel, our amazing chef, we had gourmet dinners every night, which was definitely something to look forward to during the cold days. The weather at PIG Main was colder than McMurdo, with temperatures around -10C. The temperature wasn’t too bad, but what made the camp a challenge was the wind. The winds blow from the south consistently as cold dense air from the transantarctic mountains roll down the continent towards the ocean. David was spotted chasing a tent across camp on our first day, which luckily he managed to track down. Here what PIG Main camp looks like:

Our first stint at PIG Main was only for two days, which we spent setting up our tent experiment. We set up three tents with a 4 foot semi-circular snow wall in front of them, and another 1 foot snow wall in front of that. This was a setup that a mountaineer had recommended to us for minimizing snow drifting around your tent. Snow drifting is definitely a real problem at PIG. During our second stint at PIG Main, most mornings I would wake up to a tent door which had a snow drift halfway up it. Usually this required some sort of ninja move to actually get out of the tent. We also set up a snow fence beside our tent setup so that we could compare the volume of snow collected by the fence and the volume collected by the tents. We had a camera take a photo of the tents every 4 minutes, so that we could get a time lapse video of the drifting.

After setting this up, we hopped back on the Twin Otter and flew down to the glacier to Drill Camp C. When we arrived everyone was in a good mood because the science had been going unexpectedly well. The team had already managed to drill through the ice shelf and put instruments into the ocean below at sites A and B, and they were just wrapping up at site C when we showed up. The ocean instruments are collecting temperature, salinity, and current data at three sites below the glacier. The drill camp was a much more basic than the main camp, and including us, there were 9 people in total: Sal, the cook and camp manager, Einar and Forrest, our mountaineers, Leo and Kaya, who are from Penn State and doing radar and seismic work to determine the thickness of the ice and the depth of the ocean cavity, Mike, who is from the British Antarctic Survey and is also doing radar measurements, Doug, an engineer to help with the redeployment of the seismic stations, and myself and David. The camp was a lot of fun and it was a great group of people. PIG Main had a number of permanent structures, but the drill camp only had tents. We had a science tent, a galley, a tent for cooking, and each of us had a personal tent. It was a beautiful location and from our spot on the ice shelf we could see some mountains to the east and the ocean was straight ahead to the Northwest. Here are some of the crevasses in PIG, as seen from the Twin Otter, and our drill camp:

Another nice thing about the drill camp was that the weather was beautiful! Most days the temperature was around zero and there was essentially no wind. My biggest problem weather-wise was trying to stay cool well sleeping. We started off with our main task, which was digging out the GPS/Seismic stations and retrieving the data. The stations were in a 1km grid centered around camp and we could get to each of them by skidoo. Most stations were buried about 3 or 4 feet under. The digging wasn’t too bad, but the tricky part was that most of the cables had a bunch of ice around them, so we had to become amateur paleontologists to chip the ice away without cutting the cables. We had a few close calls, but managed to do all the stations without destroying any cables. Each GPS station has a power station with solar panels and wind turbines and also has a large antenna, which picks up signals from satellites orbiting the earth. The seismic stations are similar, except they have a seismic sensor instead of an antenna. Here I am getting psyched up for a new digout.

With some serious help from Doug, we managed to get all 5 stations dug out in a few days. We also moved the stations all back to the surface, to make the dig out as easy as possible for the next person. Seth White, the guy who puts together the GPS stations always puts a little figurine in the GPS box for good luck. Here I am with all the guys we found:

The GPS stations performed really well, and all the stations essentially recorded smoothly for the past year. The seismic data had a few more issues, as one station shut off in April, but the other stations had data for most of the year, so there should be some interesting information in that data set as well. Here is a plot of the GPS data for all five stations. The stations started in the bottom right part of the plot, and moved roughly 3.5km downstream (northwest) over the course of the year. We will analyze this data in more detail later to see if the glacier is accelerating at all, to look for tidal influences, and to compute the strain rates in the ice.

After the GPS/Seismic stations were done, we moved on to collecting a small ice core for some scientists at Woods Hole. This basically amounted to drilling a 9m hole in the ice, and shipping back the cylinders of ice to the U.S. As you drill down further, you keep on adding extra length to the drill shaft, until things start to get a little ridiculous. Here I am trying to get an 8m drill down the borehole!

After we wrapped up the ice core, we flew back to PIG Main. The flight back was amazing! A few years ago PIG developed a huge crack across the glacier, as seen in the image below. In this image you can also make out a scar in the glacier upstream of the spot where the two cracks meet. That scar is the path that the PIG Drill camp traversed between sites A, B, and C. We were tempted to write a message in the ice that would be visible from space, but ran out of time. Our pilot took us for a tour of the crack on our way home, and it was incredible. We flew right up to the crack and then eventually flew right into it! We had walls of ice on either side of us and ocean water below. The crack is probably about 4 planes wide, so it definitely felt up close and personal as we were flying through. The second photo is the ice at the start of the crack, and the third photo is us actually in the crack. After the crack ended, we turned right and flew toward the ocean and saw the beautiful sheer vertical face of the glacier. The vertical face in the last photo below is about 50m high, as the ice shelf is about 500m thick. It was awesome!

At this point, we had completed our main objectives and were ahead of schedule, so we decided to attempt to digout the AWS (Automated Weather Station). This decision would lead to a lot of pain in the forthcoming days (see photos from first blog post). The AWS consists of a tower and two solar panels, each of which were buried about 11 feet in snow. The digout took three days of nonstop work, but we finally got all three elements excavated. As we got deeper, we found it harder and harder to shovel and eventually we had to start shoveling our snow onto an intermediate platform and then throwing it out of the hole. Also, the deeper we got the harder the snow would get, and eventually we couldn’t break it with the shovel, so we had to bring in a chainsaw. The ice pit was definitely not the ideal location to have my first chainsaw experience (I’m sure my Mom is cringing right now).  Here are the two of us in the holes we dug out.

Once the AWS was freed, we loaded it into the Twin Otter and flew back down to Drill Site C to install it. The installation took about 5 hours and the station is now up and running and working well. It will send back hourly measurements of temperature, wind speed, humidity, incoming short wave radiation, outgoing long wave radiation, snow accumulation, GPS position, and also two photos every hour. The solar panels are roughly 9 feet above the ground and given the glaciers flow speed, the station will be in the ocean in about three years. It will be interesting to see what happens first: the panels getting buried or the station ending up in the ocean. I am hoping for some cool photos as our station takes the plunge! Or maybe it will end up floating on an iceberg. Either way, this station is in for an interesting future.

After the AWS install we flew back to Main camp. It felt great to be done! I celebrated by sleeping in late on Saturday. It was nice to finally have a day with nothing on the agenda. I spent the weekend hanging out with some people at camp, making friends with Dewars, and working a little bit of processing our data. The herc showed up, and I am now on the plane back to McMurdo. It’s been an awesome time! Thanks for reading and Go Jets Go!