Archives par étiquette : Scientific facilities

Memory

Over the past two weeks, Claude, our mechanic, has devoted most of his days to end-of-winter snow clearance operations.

In particular, he has been removing the snow that the wind has built up in the two pits that form the access ramps to our cellars.

On Sunday, after a *rather* heavy lunch, we went for a walk with Claude and Jacopo to see the results of his work and discover these places that I didn’t know yet.

We started with the ‘balloon cave’. This cave takes its name from its special construction technique, imported from Scandinavia: a pit is dug, a gigantic balloon is inflated, snow is put back on top, little by little, allowing it to settle and, after a few weeks, the balloon is removed. All that’s left to do is close the entrance and we’ve got our cellar!

This is used to put our vehicles into winter storage, protecting them from the wind and snow and limiting their exposure to the cold (apart from the surface layer, the ice on which our station sits has a constant temperature corresponding to the average annual temperature of -51°C).

In fact, all these vehicles are unusable below -45°C because the plastics would break and the fuels would become pasty. Only our robust, old-fashioned, all-metal ‘loader’ works in winter (and even then, it has to be stored and started ‘warm’, i.e. at -30°C).

When you see this photo, you may realise the work Claude has done: the accumulated snow (although not packed down) reached the surface, some ten metres above our feet!

Leaving the balloon cave, we walked a kilometre through the summer camp to reach the second cave.

The technology here is a little different, as the walls are made of metal. This is the ‘Turbosider’ cave, named after the company that makes the structure.

Here you can see the ice crystals growing on the walls, giving the place a fairytale-like appearance.

While the contents of the first part of Turbosider resemble those of the balloon cave (vehicles in winter storage), at the back there’s a door.

And behind that door is a long, icy corridor stacked with dozens of crates. These contain, in particular, Concordia’s « archives »: the reserves of ice cores taken during drilling operations to study our planet’s past climate.

Concordia was built on the site of the first « EPICA » deep drilling. Some of the fragments contained in these boxes are 740,000 years old!

A new drilling has been underway for the past 3 years, at the « Little Dome C » site, 37 km from Concordia. This summer camp is in fact the site chosen for the « Beyond EPICA » project, the aim of which is to reach the oldest ice in the world: certainly more than 1 million years old and possibly 1.5 million!

These caves and crates are also the forerunners of another scientific project that is currently being developed at Concordia: the « Ice Memory » project, which aims to store samples of ice cores from the Arctic and glaciers around the world here, under cover, in order to preserve them for future generations.

A Song of Ice and Shovel

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A few days ago, I accompanied Damien on one of his outings.

Damien is one of our two glaciologists (there are a French and an Italian ones). Well… he is not originally a glaciologist: he is a cryogenic systems engineer. He is the only one of us working here in a warmer « environment » than his usual professional « environment »!

(In fact, none of the overwintering scientists are really working in their original field of expertise. Why not? Because all the experiments are set up in summer. The job of the wintering scientists is to maintain the installations, to collect the data and to transmit them. So you have to have a good scientific background but not necessarily be a specialist in the specific field).

Twice a week, Damien has to go to the « Clean area » to take samples. This is a large area, access to which is prohibited in order to preserve the purity of the snow.

But before going out, you have to cover yourself up because it is -64°C and, as there is a bit of wind, the windchill is -81°C.

First, the silk balaclava… © Stéphane Fraize / Institut Polaire Français / PNRA

… then the fleece balaclava… © Stéphane Fraize / Institut Polaire Français / PNRA

… then the neckband… © Stéphane Fraize / Institut Polaire Français / PNRA

… and finally googles and capka! © Stéphane Fraize / Institut Polaire Français / PNRA

Damien tries on a mask lent to him by Vincent. It is supposed to limit the problems of fogging in the mask.

It makes especially nice breathing plumes.

© Stéphane Fraize / Institut Polaire Français / PNRA

It is 2.20 pm, the sun is already setting behind « Astro shelter ».

And after 15 minutes of walking, we arrive at « Atmos shelter ».

Sunset over Astro shelter © Stéphane Fraize / Institut Polaire Français / PNRA

Arrival at Atmos shelter © Stéphane Fraize / Institut Polaire Français / PNRA

Despite the anti-fog conscientiously applied before leaving, I am almost blind when I arrive.

A short break in the warmth, the time for Damien to do some manipulations and prepare the tubes and bags necessary for the three different types of samples he has to take today.

Calibrated bags © Stéphane Fraize / Institut Polaire Français / PNRA

The first samples are of nitrates and sulphates from the atmosphere, which are deposited with the snow. As long as you don’t pee in the snow (!), there is no real risk of contamination and they can therefore be taken directly next to the shelter. Their results will be correlated with the atmospheric ozone measurements made by one of the shelter’s machines.

The most superficial layer of snow must be recovered. To do this, Damien starts by scraping the surface with a DIY shop spatula and recovers the small ridge thus formed with a candy shovel! (As is often the case here, we have a mixture of ultra-precise high-tech and DIY elements… but it works!)

It is time to go to the Clean Area. We follow a path marked out by stakes, from which we must not deviate.

At each round of sampling, Damien puts a marker and the next round will be done 10 steps further. This year it’s on the left side of the path, last year it was on the right.

En route to the Clean area © Stéphane Fraize / Institut Polaire Français / PNRA

Once he has arrived at the day’s marker, Damien sets off at right angles to take five pairs of samples every 10 steps. These samples are intended, on the one hand, to study water isotopes and, on the other, to measure the density of the snow.

For the latter measurement, a small hole must be dug and then two samples taken (at the surface and at a depth of 7 centimetres) using a small probe whose volume is very precisely calibrated (when the snow is too compact, the hammer is needed to push it in!)

The density can change considerably within 10 steps and, for the first time since his arrival, one of the samples was not possible because the surface was so hard.

After half an hour, the sampling is finished, the sun has gone below the horizon and it is really cold. It is time to return to the shelter.

Damien is happy! © Stéphane Fraize / Institut Polaire Français / PNRA

3.50pm, back to the station with some pretty incredible colours. It is -82°C, we are exhausted.

America, America!

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I am going to introduce you to one of the most fascinating, and dangerous, buildings in Concordia Station: the American Tower.

It is not easy to find precise information about this tower. It is one of the oldest buildings on the base. In the early 2000s, even before the construction of the permanent station, this tower was built to house a NASA science project.

Afterwards, our American friends decided they had enough to do with their McMurdo and South Pole stations and left this strange structure to the French and Italians.

Located 1 km from the base, it was then 35 m high before being raised by about 15 meters.

It is now home to a number of meteorological measurement instruments, others dedicated to monitoring the movement and temperature of snow cover, as well as an ESA facility: DOMEX, which serves as a calibration site for radiometry satellites studying soil moisture or sea surface salinity.

Damien, one of our Glaciologists, and Davide, our mission leader, have to go there regularly to maintain the installation and, in particular, to defrost the measuring instruments. This is an operation that must be carried out at least once a week.

At the moment, this is still done under the sun, with actual temperatures of -40°C at the « hottest » part of the day, which gives felt temperatures of -50 to -65°C taking into account the windchill effect. And at the top of the tower? Well, at the moment, it’s worse. (During the polar night, it’s more complicated: it’s often warmer at the top of the tower than at the base, but with more wind, so…)

I’ll let you imagine what this defrosting exercise will mean during the polar night when we will have lost another 20 or 30°C of temperature.

That’s why this is one of the two facilities where it’s mandatory to go with at least two people, and three when it will be the polar night.

Four days ago, it was me who accompanied Davide.

Davide is Italian. He usually runs a particle physics laboratory in Padua. At Concordia, he holds the somewhat catch-all scientific position of « Electronics for science ». He is in charge of maintaining a whole bunch of scientific installations in a wide variety of fields: seismology, geomagnetism, atmospheric observation, meteorology…

He is also the one who has been appointed as the DC19 mission leader and we couldn’t imagine a better choice. But I’ll tell you about that another time…

For the moment, it’s time to come with us to the American Tower!

See all the little landings? Each one is about 2m high.
©Stéphane Fraize/Institut polaire français/PNRA

Like every scientific facility, the American Tower has a shelter that is heated (depending on the situation, to +4°C, +8°C or +15°C). Some are under the snow, others on the surface. And still others, like the American Tower’s one, were originally above ground and are now well below the snow level.

The first step is to go down into the shelter to fit ourselves with harnesses. At the base of the tower, we attach our harnesses to a « life line » that goes up to the top of the tower.

We can then start our ascent and Davide starts to defrost the sheaths and instruments as we go along. Normally he uses a large brush but this one was broken and, on this day, he did it all with his under-gloves. Luckily we had our heaters in our mittens.

And so, landing after landing, we reached the top of the tower. Or almost, because the last two landings don’t have instruments and we weren’t going to be overzealous.

The weather was rather calm but, in spite of that, we could feel the top moving!