30 March 2016

Mark Eijkelboom joined an expedition to East Antarctica as a technician

"When doing measurements, we occasionally walked around in our thermal underwear"

Mark Eijkelboom, technician at IMAU, has just returned from an expedition to East Antarctica. In the BENEMELT project, researchers Jan Lenaerts (Utrecht University) and Stef Lhermitte (KU Leuven) study the melting of the upper layers of ice shelves. “We were there with a group of eight people: Stef and I from BENEMELT, two researchers from the IceCon project and four guides from the Belgian Army, who provided excellent support.” The researchers hope to gain a better understanding of the stability of the ice shelves on East Antarctica.

How does such an expedition work? Eijkelboom: “We flew to the Belgian Princess Elisabeth Base on Antarctica, where we stayed for a few days to test our equipment and re-pack. Then we travelled 200 kilometres on snowmobiles to our base camp at the King Boudewijn ice shelf, where we stayed for three weeks. The base camp consisted of a container with a small kitchen and a table where we could eat and work, plus a tent for everyone. The food supplies are stored outside, because Antarctica is one big refrigerator.”

 

Photo gallery
Stef Lhermitte measures snow grain size in temperatures just above freezing.

“It was surprisingly warm on Antarctica. It was high summer in the southern hemisphere, so the sun never set. When the sun began to rise up around two in the morning, you could hear people unzipping their sleeping bags all around you. Most nights, I slept on top of my sleeping bag in my thermal underwear. Sometimes, during the day, you wanted to take off your shirt, but that’s not a good idea because the sun is so intense. It got so warm, in fact, that we could go out in our thermal underwear to take measurements.”

Installation of the weather station in December 2014. © Jan Lenaerts

“My mission was general technical support for the installation and maintenance of the scientific measurement equipment, but also to repair the snowmobiles. Things often broke down due to the extreme conditions, but luckily I was able to repair everything. One of my tasks was to disassemble the weather station that had been set up in 2014, and that had reached the end of its service life. When we got to the weather station, we saw that it had been buried in one and a half meters of snow. Fortunately, there was a snowcat nearby to help dig out the station.”

Broadband albedometer

“The expedition’s goal was to conduct all sorts of measurements on the ice shelf. That included measuring the reflectivity of the ice using a spectrometer, which measures the difference between the amount of light that comes through the atmosphere and the amount reflected from the surface. If the surface reflects less light, then it is absorbing more light and heat, which means that it will melt faster.”

This ice core sample shows a period of high melt levels​.

“We also measured the composition of the surface, to see where the levels of snow and ice are located, along with their density. That tells us something about the climate conditions over the past few years. We primarily conducted those measurements using radar, but we also collected lots of core samples of up to eight meters deep in order to calibrate the radar measurements. To take a core sample, you use a kind of apple corer to bring a cross-section of the snow cover up and examine its composition. Since it often got so warm, we had a tent to allow us to take the samples in the shade.”

Our camp in the circle. © Sanne Bosteels

“As part of the expedition, we travelled to a 'mysterious circle' that observers in an airplane discovered last year. It was another 300 kilometres from the base camp by snowmobile, to a place that no one else had ever visited, so it became a real voyage of discovery. We were able to study the phenomenon for a few days, and we expect to be able to publish an article about it in the near future.”

Covax hand drill in 2.5 meters of ice-cold water.

“We were very pleased with the guides from the Belgian Army. They set up the base camp for us, prepared our meals and helped us get from place to place. We occasionally faced life-threatening situations, where the ice was thinner than expected, with meters of ice-cold water below. They also helped out in other ways, like when two of our guides fished a drill out of the water for us after it fell through the ice.”

Reinhard Drews and Nicolas Bergeot (IceCon) measure the ice shelf using low-frequency radar. © Eric Vroonen

“We did something useful every day of the three weeks we were on the ice. That gave us a sense of satisfaction, because such an expedition costs a lot of money, so you want to get as much out of it as possible. We were really fortunate with the weather down there. And we also enjoyed the cooperation with the IceCon researchers, as both teams were able to use one another’s observations.”

BENEMELT during a long traverse.

“We travelled almost 2,000 kilometres by snowmobile during the expedition. Sometimes we had to travel for hundreds of kilometres per day over an unchanging landscape, where there was nothing to see but snow beneath you and sky above. That’s when you realise that you’re a long way from home, and that you’re strongly dependent on your equipment and each other.”