Posts Tagged ‘West Antarctic Ice Sheet’

SEAT: Satellite Era Accumulation Traverse: Camp Life

January 24th, 2012 by Maria-Jose Viñas

By Michelle Koutnik

This is one of our six camping sites. The Scott tent is the big yellow tent and the others are the sleeping tents. The bathroom is at the end of the site.

Each of our six different camping sites consisted of one cook tent, four sleeping tents, and a bathroom area (more on that later). The cook tent was a “Scott” tent, which is an enduring style and named for the polar explorer Robert Scott. It was a tight space for five people but we were able to crawl in and then sit around together with one person managing the two-burner propane stove in the corner. The Scott style tent was much sturdier than our mountain-style sleeping tents, but it was also more time consuming to put up and heavier to transport. Since we were moving nearly every other day, we wanted to keep our camp as simple and as light as possible. The Scott tent was a necessary addition for cooking, but also as a reliable shelter in the two strong storms we experienced during the traverse.

Camp with our snow machines and the radar sled.

It took a few hours to set up camp, and a similar amount of time to break it down and repack the gear on the sleds. Randy, Jessica, and I were responsible for breaking down most of the camp and for setting up some of the camp on our own while Clement and Ludo collected radar data on traverse days. Once camp was set up at a new site, we could start melting snow for water and start cooking dinner.

On a traverse day, our camp life included the take down and setup of camp, plus collecting radar data. On an ice-coring day, our camp life included digging and sampling the snow pit, drilling the ice core, and eating a hot lunch. We ate well out there! Our standard meal plan included tortellini with pesto, spaghetti with meatballs, sausage with rice and vegetables, and burritos.  Sausages were popular and made their way into many meals. Special nights featured hamburgers with tater tots, and on Christmas we cooked scallops with rice and vegetables. Hot lunch on ice-coring days featured cheesy bagels fried with butter in our cast-iron pan. Since all the cheese and bread was always frozen, it required frying it all together before we could eat it – but it tasted great this way! Stormy-day food was simplified but did afford us the time to enjoy pancakes (two storms, two pancake breakfasts).

Frying cheese and bagels in butter for lunch.

The storms also affected our standard bathroom situation – usually a snow pit and tarp configuration. Ludo took the high winds and blowing snow as a challenge and created a snow-brick bathroom, which we tried our hardest to maintain from drifts!

Snow-brick bathroom and camp after a storm.

Maintaining camp and completing the science goals was a big job but we enjoyed being out on the ice sheet. For example, Christmas was a wonderful day to share together because a big storm started to clear, and we had lovely gifts to exchange, two small Christmas trees, and a very nice meal. Overall, the camp life was comfortable and enjoyable and with such a hard-working team, we were efficient at all the tasks necessary to make the camp run and be successful with the science.

Traversing to a new camp site.

SEAT: Satellite Era Accumulation Traverse: Radar days on the West Antarctic Ice Sheet

January 23rd, 2012 by Maria-Jose Viñas

By Clement Miege

Hi there! After more than three weeks spent in the field, our team is very happy to be finally back, with many memories of the traverse. This year has been a very intense experience and I would like to tell you a little more about this expedition. I will focus on the days we were doing radar surveys. Indeed, two different studies were set up during this field work. The first one was during the traverse days, where we did a radar survey from one camp to another with a range of 50-90 kilometers (31-56 miles) between the camps. On the other days the surveys were smaller, set up around each camp; they consisted of a 10-km bowtie and a 280- by 280-meter (918- by 918-ft) grid to get a better idea of the spatial variability of snow layer depth surrounding each core site. These grid surveys will show us how representative the ice core is compared to the surrounding area and help answer the question of whether we would have gotten a different result if we had drilled our ice core a few paces this way or a few paces that way. We were also looking more in detail at the layering in a 2-meter (6.56-ft) snow pit; to do that, we were using a metal plate at different depths of the snow pit.

The radar is sitting on a triangle-shape sled that is pulled by a snowmobile.

Here is a picture showing the two radars that operated simultaneously on the sled:

Both radars looked at the first 20 meters of the snow pack, sending electromagnetic waves into the snow. The snow radar (the big green horns in the picture) operates in a frequency range of 2-8 GHz. The other radar (the smaller brown horns) is the ku-band radar, sweeping between 12 to 18 GHz. The lower the frequency, the deeper the radars look. We have both radars for some redundancy in the system, imaging the snow/firn closest to the surface, which we core twice, and then the snow radar peers deeper than the cores to provide literally a deeper look. In addition to the 2 radars, we needed to know the elevation we were at, which is important for comparison with airborne data and also for modeling precipitation and temperatures. For that, we simultaneously collected GPS coordinates, which gave us our exact latitude, longitude and elevation every 5 seconds. The GPS antenna was on the very top of the sled, about 2.5 meters (8.2 feet) high.

On this sled, beside the radars sitting in the red box, we had packed: a blue bag, two black duffel bags and an orange bag. The blue bag was a survival bag, with all the gear needed in case we would have been caught in a storm; it included a tent, a stove, a shovel, and some food. The two black bags contained Ludo’s and my sleep kits, and the orange bag had some extra food, in case we were stuck for couple days. For the snow mobile, we had a repair kit under the seat to troubleshoot a possible failure. We were carrying two extra cans of gas as well. With this set-up, we were able to get a pretty light sled that was still comfortable and had all the gear we’d need in case of a storm or other circumstance separated us from the rest of the team, who were carrying all the camp gear. Fortunately, this never happened!

But now, let’s go back to the survey. The travelling days were the ones where the team was the most vulnerable: while we were traveling we had no shelters or camp set up to get back to if anything went wrong because we had to break down the entire camp in the morning, pack all gear on the sleds and ride with the snowmobiles pulling the sleds to the next camp. After driving between 50-90 km (31-56 mi), we would build our new camp, usually that same day in the afternoon. We had a total of seven travel days, covering a distance of about 500 km (310 mi).

Our sleds at camp. Strapping all your gear on the sled takes time and requires inventive skills; we called this the art of “Strapology”!

During travel days, the radar team left camp first, mostly because we had to drive at low speed to ensure the radar’s safety. Indeed, on the days we ran into large sastrugi (small ridges of hard snow), we drove at less than 10 km/h (6.2 mph). These sastrugi made our travel a little bit more difficult. Toward the end of the day, the team responsible for breaking down camp would leave the radar team and go 20 km (12 mi) ahead, to start setting up the new camp.

The days we were at camp, we did some small radar surveys: a bowtie and a grid around the core site. To help us drive the snowmobile straight for the grids, we set up flags to visualize the corners and sides. In the deep field, everything is white and flat, so it is hard to maintain a nice bearing just by following the GPS for such a small grid.

Clem and Michelle, getting ready for a short walk to set up the grid flags.

The last side survey with the radar was done in the snow pit. After analyzing the snow pit and picking up snow samples for further laboratory analysis, we used the pit to calibrate the radars and look at a detailed snow layering for the top 2 meters.

Ludo in the snow pit, sliding a metal plate in the snow at different depths. The plate creates a very bright horizon that is easily detectable on the radar return signal.

After a day of travel or after doing a grid, it is important to back up the radar data. The sleeping tents are a warm and cozy shelter to set up a “recharging station”. In addition to backing up the radar data, we recharged the satellite phone, GPS, and computer batteries.

We had to check the integrity of the radar sled at each camp site. Here is Ludo, checking the screws on one of the three legs connecting the snowboard to the sled.

To conclude, I want to say that this traverse was definitely an amazing experience and I was happy to share such a good time with the team. I am already excited to start looking at the radar data in detail to see what we can learn of the past few decades of snow accumulation in this part of the West Antarctic Ice Sheet.

Notes from the Field