Tuesday, December 18, 2012

Return after a successful field trip

The IceCon team is back at PEA after a successful trip to the Derwael Ice Rise. So here is a brief update of the activities that took place during that two-weeks period.

Morgane proudly showing a piece of core
It took 22 hours to get to Derwael Ice Rise, driving all day and all night. Once camp established, the ice core drilling operations started. This went quite smooth for the first tens of meters, but a series of problems occurred, especially near a depth of 60m, where further drilling became seemingly impossible. Nevertheless, thanks to the continuous efforts of everyone around camp (drillers, support people from BELARE such as Kristof and even an inventive approach from the field guide Raphy), they finally got through that difficult bit and succeeded in drilling up to 120 m of core. At that depth, the ice seemed rather hard to go through and it is not clear for the moment what the origin of this could be. The site is on an ice rise, influenced by the Raymond effect and therefore different from other areas where a similar drill has been used. In the end, the televiewer was lowered down in the borehole to completely image the internal structure, which will make it possible to count internal layers within the firn part and maybe beyond.

ROB1 power station and receiver
From the beginning of the field activities we also started on erecting the ROB1 cGPS point. This takes a bit more time than the ULX1 point on Seal. It consists of digging a large snow pit to lower down the power plant (batteries, solar panels and wind turbines). Digging was also the key word for mounting the GPS antenna and securing the whole thing for winter. After a couple of days, ROB1 was operational and setup as a base station for all other GPS activities that were carried out in the area.

Coffee-can marker: a steel cable goes via two
pulleys through a hole in the firn where it is
held tight with an anchor. 
Digging continued to make water for hot water drilling. Since ROB1 is on the ice and prone to vertical ice movements, we need to have an insight into the processes that govern that motion (compression and strain). Therefore, we set up a series of markers at different depths in the firn, ranging from 10 to 50m of depth. These markers are a steel cable anchored at depth and connected to the surface. Every year, the length of the cable will be measured, leading to a series of relative displacements. The hot water drilling required 2500 liters of liquid snow, which implied digging, melting and hosing. This took a day and a half to do and in nice weather was quite a leisurely job. Drilling in itself took less than an hour (it is like cooking a meal for hours and finishing dinner in 10 minutes). The so-called coffee-can markers (designed by Kristof and Greg at PEA and field proven afterwards) were thus easily installed.

Denis and his high-frequency radar: whenever it goes well,
it is a boring job to do!
On and around the Derwael ice rise, an intensive network of high- and low-frequency radar lines have been surveyed, revealing not one Raymond bump, but two. Moreover, the quality of the data is superior to the data gathered two years ago during the BELISSIMA programme, so that we are sure to have a complete 3D view of the dome area. Besides a strain network was established around the dome so that we can monitor the horizontal deformation precisely.

Besides the IceCon project, the Be:Wise project was also very successful. They established camp on the Roi Baudouin ice shelf and surveyed near to 180 km of radar data (both high and low frequency) and monitored 20 stakes on horizontal and vertical displacement using precise GPS. The markers will be re-surveyed next year.

Be:Wise: don't fool with us, because we are professionals!
In short, more than expected has been done in relatively little time. The spirits in camp were always high and it was a fun thing to do. We could rely on a professional support team and surely, the good and balmy weather made us work every day. It is Antarctica, but also the coast, and recorded temperatures were regularly positive.

The return trip was more of a burden with poor visibility, bad and soft snow conditions and too high temperatures on the ice shelf so that the hydraulic system of the Prinoths went to high so that we had to stop at regular times. It took us a bit less than 30 hours to return to the station.

Friday, December 7, 2012

Operations at derwael ice rise

It took 22 hours of travel with two Prinoth trains to Derwael ice rise. Departure was delayed due to a few mechanical problems and we arrived by 7 am on Monday at the camp spot. It didn’t take long to get everything into place which meant that the science activities started later on the day (December 3, 2012). The weather has been very nice, warm and mostly cloudy with light snow fall. Ideal weather to pursue the activities. After three days, ROB1 was installed on the snow (or better dug in into the snow), which involved a lot of digging and snow removal. The GNSS antenna pole was put at a depth of 2m below the snow surface.

Drilling operations went rather smoothly, thanks to extensive testing at PEA. After three days, a depth of almost 60m was reached. Only few melt layers were detected in the upper firn part.

All radar profiles around Derwael were swiftly run. The first day (4 December), 70 km of low-frequency radar data were collected, clearly showing the different aspects of the Raymond bump, as well as a side bump to the south of the ice divide (the highest point on the ice rise where the major bump is situated). The origin of these bumps are due to the ice rheology. Ice deformation underneath an ice divide is essentially due to longitudinal stretching of the ice layers, while away from the divide, vertical shearing becomes more important. Due to the nonlinear nature of the flow law for ice, this leads to a higher effective viscosity under the divide, making the ice less easy to deform under the divide compared to the flanks. The result is that ice layers on the flanks are at greater depth on the flanks compared to the divide, leading to an upwarping of layers under the divide. This effect has been theoretically put forward by Charlie Raymond in the 1980s, but only observed for the first time with radar almost 20 years later. It is therefore commonly known as the Raymond effect. As a result of this effect, the ice core will reveal ice of an older age at depth compared to a position situated on the flanks.

Today, December 7, the Be:Wise team is ready to move their advance camp to the Roi Baudouin ice shelf.

Sunday, December 2, 2012

Friday, November 30, 2012

Final preparations

Planned field work operations at Derwal ice rise (right) and on the ice shelf (Be:Wise project)
All equipment has been thoroughly tested and the Eclipse drill is working. Final preparations for the cargo train towards the coast are on their way. Yesterday the weather deteriorated and the whole morning until mid afternoon there was a lot of wind, making operations difficult. The plan is to depart early morning on Sunday, if everything goes well. In the meantime there is plenty of work for everyone in getting the final planning together, checking and double checking cargo and requirements or resting before embarking on a very long trip towards Derwael ice rise.

A presentation of the science of IceCon, given last night at the station for all station personnel and other vistors can be downloaded on the Publication page of this website.


Wednesday, November 28, 2012

Field training

View from within the crevasse
Field training is part of Antarctic research activities. The ice sheet is not a safe place: as the ice slowly moves from the center towards the edge, it cracks and opens up at the surface due to tension, especailly when the ice moves across an obstacle (subglacial bump or mountain). Those cracks, called crevasses, are usually covered by snow, which means that they are hidden. Most of the areas we will visit are safe, meaning that crevasses are not present, but one should be prepared.

We went to a crevassed area 9 km from PEA to do crevasse training and rescue. Each of us was lowered safely in the crevasse, 20m down and then pulled up by two simple techniques, one involving a pully system anchored on a skidoo, another technique using two skidoos, in which the pully was done by the second skidoo. The latter goes fast of course :-)

The crevasse itself was very impressive, with beautiful snow crystals inside, as well as very silent (compared to the buzz at the surface). The field training ended with the immobilization and transport of a person that was injured (fictively of course, and perfectly mis-en-scène by Bryn) to PEA.


ULX1 installed

Installing the antenna on the ULX1 mast.
On Tuesday 27 November, the geodetic continuous GPS system was successfully installed on Seal Nunatak, a small rock outcrop next to the former Japanese Asuka station, approximately 60 km from PEA. The area is particularly known to be windy, which is very nice from the point of view of energy supply via our wind turbines, but less interesting if one needs to install the GPS mast and the power supply box at the top of the nunatak. Fortunately for us (Alain, Raphy, Nicolas and Frank), the conditions were quite balmy, with only a 20cm high wind drift around the rock (while at PEA there was no wind at all!). The reason why it is so windy is that the site is further to the east, hence less protected by the mountains from catabatic winds. (Catabatic winds are gravitationally driven winds coming from the polar plateau and picking up speed while making there descent towards the coast)

The fixing and drilling of the mast and the battery box was done by Alain and Raphy, while Nicolas and Frank installed the solar panels, wind turbines and powered up the whole system. Luckily it was all tested at PEA before, because the windy conditions do not leave much room for quiet analysis of what to do next and reading the manual at ease. All systems seem to work, the solar panels produce the bulk energy and wind power is only used during absence of sunshine. However, the latter could not be checked completely, unless we decoupled the solar panels from the system.

Instalation on Seal Nunatak of the GPS mast ULX1, the battery box and receiver, solar panels and wind turbines.
The system will now run continuously for several years. The consumption of energy is rather low, and the batteries are charged via solar panels (summer) and wind (winter). Once they are charged above 13V, they will charge the internal battery of the receiver, which in view of the low consumption should be sufficient to get us through this whole period without major maintenance.

The cGPS is meant to measure tiny horizontal and vertical motions of the Earth's crust due to tectonics as well as uplift due to changes in ice mass (in response to a bigger ice sheet during the Last Glacial period). This information will be extremely useful to constrain GIA models (see the IceCon project page for more information on the subject).

Fixing the monument into rock

Sunday, November 25, 2012

Instrument testing and calibration

Setting up the Eclipse ice corer
Weather is nice and warm (at least during the day) with very low wind speeds. This allowed for extensive testing and assembling of the equipment. The drill team (Jean-Louis, Bryn and Morgane) are in the process of assembling the Eclipse corer that will be employed for drilling an ice core at the ice divide of Derwael ice rise.

The radar/GPS team (Kenny, Reinhard and Denis) is then quite happily busy with testing the 5 GPS systems that will be deployed to measure a strain network on Derwael ice rise and several continuous measurements on the Roi Baudouin ice shelf with the purpose of establishing the effect of tides on the ice shelf at different places across so-called shear margins on the ice shelf (weaker zones where ice acceleration is expected). The latter is within the framework of the Be:Wise project.

Nicolas testing the cGPS data at PEA
Finally, the geodetic GPS team (Nicolas and Frank) set up and tested two cGPS systems. The first one to be set at Seal nunatak (near the former Japanese Asuka station), and one one the Derwael ice rise (shown here). Both systems are different in the setup and power. They will run autonomously during several years. The battery box contains 10 batteries (more than 400kg!), which are powered up by both solar panels and wind turbines.


Thursday, November 22, 2012

Arrival at PEA

Arrival at PEA, view from the station's window on Utsteinen Nunatak
All went smooth. We departed from Cape Town at 23h30 and arrived at Novo airstrip a bit more than 5 hours later. The Ilusyin aircraft was offloaded in no time and the Bassler loaded for the first feeder flight of two. By 10h30 local time a first group of six people arrived at the Princess Elisabeth Station. The remainder will fly in tomorrow (weather permitting of course).

After a tour of the station's facilities, most people went to work to check instruments, verify the arrived cargo and we started with the preparations of the upcoming field work. As mentioned before, a lot needs to be done and all tasks require quite a lot of logistic support. The first thing to do is to install a GPS station at Seal (a nunatak next to the former Japanese Asuka station). After that we'll head for the coast and do the work on Derwael ice rise (drilling, GPS network) and the work of the Be:Wise project that runs in conjunction with IceCon.

Scientific results of the expedition, of previous expeditions and a more detailed outline of the science plan of the IceCon project will be outlined on the project page and other pages available on this website.


Wednesday, November 21, 2012

Imminent departure

Briefing at ALCI headquarters
We had a briefing at ALCI (Antarctic Logistics Company International) this morning regarding the flight to Antarctica. We will leave at 23h30 tonight to arrive early morning at Novo air strip (next to the Russian Novolazarevskaya station). It will be a full flight with 60 people on board from different nations. From Novo, two feeder flight with Basslers (refurbished DC3's) will take us to PEA (Princess Elisabeth Antarctica), one upon arrival, and another one the next day. This means that the IceCon crew will be be split in two and arrive at different days at the station (unless the weather decides differently of course).

The last day in Cape Town means the last day to buy things that seem indispensable, the last time we have a nice meal at the Waterfront with a chilled Chardonnay (and not a drink that has been refrozen several times), the last pool, the last sauna, the last shopping, the last beach visit, the last phone call, the last ...

Well, till down south.


Tuesday, November 20, 2012

IceCon in Cape Town

Some IceCon team members in front of the new South African icebreaker in the harbor of Cape Town
The whole IceCon team made it to Cape Town on monday morning. All went smooth, no delays, no lost equipment. While the plane that will take us to Antarctica was still at Novo station on Monday (due to the delays of flight D1 and D2, the first two flights of the season), ALCI (the Antarctic flight operator) is very confident that D3 (our flight) would leave on schedule, that is Wednesday night to arrive on Thursday morning at Novo Air Base.

Cargo seems sorted out, so we have the time to linger, although the weather seems not so promising here (no spectacular views of Table Mountain, hidden in the low clouds). We checked out the boots to wear in the field this morning at the warehouse, where the new South African polar vessel was moored. It hasn't been to Antarctica yet.

Planning the field work (left to right): Kenny, Reinhard, Raphaël, Nicolas.
With all logistic operations going so smooth, there is time to plan the scientific activities in more detail: what radar profiles to measure in priority, how to set up the strain network, when to setup the GPS systems, how to setup camp, etc. Slowly but surely, the expedition falls into place.


Monday, November 12, 2012

J-7: station still not operational

According to the Antarctic Station website, the crew that needs to open the station and make it operational for the coming field season is still stuck in Cape Town. They were supposed to arrive in Antarctica on 6 November, but bad weather prevents them to leave South Africa: http://bit.ly/UdBMvN

Such delays may have consequences for the upcoming field work, although we hope for the best. We are the first team to arrive (21 November) this season and rely quite heavily on logistics involving drilling, GPS deployment and radar. If the preparations are not going according to plan, delays are to be expected.

Sunday, November 4, 2012

IceCon on Facebook

Follow the science and the upcoming expedition to Antarctica via Facebook and the Project Webpage. Regular updates will be posted here.


Thursday, November 1, 2012

Preparing the upcoming expedition

Cargo train at ULB ready for departure
The first expedition of IceCon to Antarctica is planned to leave Brussels on 18 November 2012 (until Christmas this year). We will fly to Cape Town from where we take the DROMLAN flight to Novo and further down to Princess Elisabeth Station (PES). The team members are Nicolas Bergeot (ROB), Bryn Hubbard (Aberystwith University), Kenny Matsuoka (NPI), Frank Pattyn (ULB), Morgane Philippe (ULB), and Jean-Louis Tison (ULB). We will be joined by Reinhard Drews (ULB and 2012 recipient of the InBev-Baillet-Latour fellowship) and Denis Callens (ULB) from the Be:Wise project.

Our expedition relies quite heavily on logistics. We will install two geodetic GPS systems that have to run all-year long, which puts serious constraints on power. We therefore rely on batteries charged up using both solar panels and wind turbines. One of the geodetic GPS systems will be set up on Seal, a small nunatak in the vicinity of Romnoesfjellet, but quite easy for access. The former Japanese Asuka is just next to it. The purpose of the GPS systems is to monitor over a 4 year period vertical changes of the lithosphere in response to the unloading of the ice due to post-glacial rebound. This way, we would have an idea on what volume of ice was present in the this sector of Dronnng Maud Land (Antarctica) during the Last Glacial Maximum. This information is essential to constrain models of Glacial Isostatic Adjustment (GIA), which form the basis of the interpretation of the GRACE satellite signal (see Project page for more information).

Monday, March 26, 2012

The IceCon Project

IceCon is a project funded by the Federal Science Policy Office (BELSPO) and aims at constraining past and current mass changes of the Antarctic ice sheet in the coastal area of Dronning Maud Land, Antarctica.

It comprises 6 partners of several Belgian and foreign institutions, i.e. Université Libre de Bruxelles (ULB), Royal Observatory of Belgium (ROB), University of Luxembourg (UL), Norwegian Polar Institute (NPI), and Aberystwyth University (AU).

The IceCon project aims at a better understanding of the past and present deglaciation of the Antarctic ice sheet in Dronning Maud Land (DML) through a new series of measurements and observations in conjunction with ice sheet system modelling. Our main hypothesis is that the Last Glacial Maximum (LGM) ice sheet volume in DML was smaller than that predicted by large scale ice sheet models.

Such observations are of major importance for several reasons: (i) less grounded ice at LGM implies less ice loss during deglaciation, which makes it difficult to associate meltwater pulse 1A (MWP1A) to the Antarctic ice sheet (MWP1A was an ~20 m rise in sea level in 500 yr that occurred during global deglaciation ca. 14,200 yr ago). The freshwater source for this event remains controversial, yet understanding the source of MWP1A is important because of its effects on oceanography and climate, and because it provides a potential analogue for rapid ice sheet deglaciation); (ii) correct understanding of past ice volumes are important for GIA (Glacial Isostatic Adjustment) corrections, hence interpretation of the present-day mass change of ice sheets through analysis of GRACE data.

The IceCon project aims at determining the timing of deglaciation since LGM in DML as well as the ice volumes associated with this deglaciation. The methodology relies on direct measurements as well as on the analysis of ice flow characteristics in the coastal area. Coastal DML has high accumulation rate and relatively thin ice, which provides a premier opportunity to reconstruct environmental changes recorded in ice at a high resolution rate. However, this also yields that the span of the glaciological records is limited to the past several thousand years. In this project, we will conduct glaciological studies to study the past millennia and geophysical studies to cover the LGM to present.