Friday, December 26, 2014
Thursday, December 18, 2014
|Getting the contents out of the tents during the storm at Derwael ice rise|
|pRES measurements at Derwael ice rise|
|Digging out the cGPS station|
|Drilling through the ice shelf with the Eclipse drill|
Thursday, November 27, 2014
Sunday, November 23, 2014
Saturday morning was spent to the second and the last part of the field training around Utsteinen. Only Nicolas dropped out on this one because he had to revisit the cGPS station at Asuka. Frank dropped out as well ... because of not enough skidoos around. On the program: handling the skidoo ! Now, everyone is ready to get into the field in a secure way.
The remainder of the day was spent on verifying and testing different instruments: Frank and Brice took care of the pRES, GSSI, and several GPS systems (assembly of antennas, material checking, matlab code verifications, …). A novel part of the field trip is the use of a phase-sensitive radar (or pRES). As any other radar we commonly use in polar regions, the pRES enables to determine the thickness of the ice by sending out an electromagnetic signal that bounces off when it reaches the bottom of the ice and is received back at the instrument. The wave speed through ice is known, so that the ice thickness can be inferred. However, any radar is also capable of detecting internal structures in the ice. The pRES is capable of seeing changes in the position of these structures over time. So, if you send out at exact the same place an electromagnetic signal a year later, you may detect the change in position of these structures, from which the vertical flow of the ice can be inferred. This is quite unique, because we normally don't have any direct measurement of how ice moves at it interior. At the surface, horizontal flow speeds are easily detected through a GPS measurement, but not inside the ice mass. These parameters are essential in the IceCon project, because the ice dynamics need to be taken into account to interpret our geodetic GPS signals.
Once in the field, we will drill two 30 m deep ice cores on Derwael Ice Rise, 2 km on each side of the divide, to investigate the spatial variability of snow accumulation induced by this 300 m high topographic feature. We will then move the base camp on the "Roi Baudouin Ice Shelf", where we will drill all the way down the ice shelf to reach the ocean water (about 150 meters) and investigate the presence of marine ice. This ice is in fact refrozen meltwater that accumulates under the ice shelf, influencing its stability.
Friday, November 21, 2014
Thursday, November 20, 2014
BELARE, the Belgian Antarctic Research Expedition, exists 10 years. The first expedition, back in 2004, was meant to find a suitable spot to construct the Princess Elisabeth Station. The station was supposed to be build on rock (to make it longer lasting - or at least technically more simpler as it would not be covered in the ever accumulating snow. At that time we visited several potential sites that were selected according to access, rock strength and flatness of the terrain. The Utsteinen rim was far out the best place. But there was something more interesting about that place. Since it is situated at the Western side of the Sor Rondane Mountains, it is also more protected from severe winds (especially katabatic ones) which makes it so nicec to work. I mention this, because going to Princess Elisabeth demands several stopovers. The first one in Cape Town, but no-one is going to complain about that, the second one is Novo airstrip on the Antarctic coast just off South Africa. It is a less protected side and when we arrived yesterday morning at 3AM GMT in fairly good weather conditions, we had to offload the plane in a fierce wind. Most of us are familiar with those uncomfortable conditions, but it is even more strenuous for the newly arrived who are immediately confronted with the harsh conditions of field work.
|Offloading the plane at Novo and separating the cargo for the different feeder flights|
The weather conditions gradually improved, the wind got down by 6AM, the time we went for breakfast and when the plane was offloaded. We had quite a lot of material to unpack and pack and to shift it in two heaps, each heap for a feeder flight that would take us to Princess Elisabeth station. After a nap in the barracks at Novo, the first group and cargo left at 4PM and a group of 6 stayed behind at Novo (Jean-Louis, Denis, Jan, Nico, Raffi and Frank) waiting for the next flight, that, ..., was rescheduled for the following day. A night at Novo for part of the group and hopefully by noon in at PES.
Monday, November 17, 2014
Après un vol sans encombre, nous avons retrouvé Morgane pour un premier briefing avec l’ensemble des équipes scientifiques participant à la saison Belare 2014-2015. Ensuite, repos et boulot pour certains, montée du Lion’s head avec une vue impressionnante sur Cape Town pour d’autres.