Location: Troll Station, 72º 01’ S, 2º 32’ E, 1250 metres a.s.l.
Weather: Clear, -10 C, wind 5 kts

As always, it is with mixed feelings that such a large-scale endeavour is brought to an end.  Everyone on board is relieved to see the job done, to have finished this effort in style, and to return to normal life – but on the other hand, we have had a really good time together and enjoyed some great moments on our way across the Antarctic Plateau, a truly magnificent place.  As always, there is something to be missed when a journey ends and a new one begins.

Thus we have happily, but somewhat hesitantly descended from the plateau and down to Troll Station.  We had accustomed ourselves to life in the field, and the arrival at Troll Station seemed to lie ahead of us just like any other day on the traverse.  Until we crossed the last hill into the station, we were still in traverse mode; still the outside world seemed almost too far away to matter. Then, all of a sudden, we are met by a veritable ticker-tape parade staged by the station crew at Troll, 30 persons lined up to see us break the finish tape, pop the champagne, pose for group photos, answer hundreds of questions.  There were cheers, there were hugs and handshakes, there were showers, saunas and hot tub soaks, there was a dinner with prominent guests from Norway, South Africa, Germany, and Canada, there were speeches, there were stories and toasts, there were celebrations.

And finally it dawns upon us: We’re done!  We have completed a grand voyage, we have behind us a job well done, we have a true achievement to our credit.  So, thank you to all who met us, thank you for making us feel that we have completed something significant, thank you for making us feel that you were all a part of it. 

And thank you to all of you who have followed us en route.  It has been truly inspiring!

The ”lead dog” Lasse breaking the finish tape at Troll Station.  Photo: Ken Pedersen.

Location: Gygra, 71º 57’ S, 3º 13’ E, 1550 metres a.s.l.
Weather: Clear, -25 C, wind 16 kts

We have enjoyed a very successful season, and have met virtually all of our science objectives.  Between the radars, ice cores, snow pits, gravity surveys, and thermistor strings, it is sometimes hard to keep in mind the larger picture of what we are trying to accomplish with this project.  This was the second field season of a larger four year project to better understand climate change in the Dronning Maud Land sector of East Antarctica.  There is significant uncertainty about how this region is changing, in terms of both temperature and accumulation rate.  Taken together, our experiments and measurements along the traverse route form an integrated set of observations to better understand the climate here, and how it is changing.

Ice cores

The most detailed climate information will come from analysis of the ice cores we have collected (Diary 14 Feb).  Back in our labs in Norway and the United States, we will measure the chemistry and physical characteristics of these cores to determine how much snow falls at the coring sites each year, and how that snow fall rate has changed through time.  The hand-drilled cores will span the most recent 50 years; the 30m cores we collected at sites 2, 3, 4, and 6 should record the last 200 years of changes; while the longer cores from sites 5 and 7 should reveal more than 1000 years of climate history.  These measurements take time, and won’t be completed before 2010.  As with so many other aspect of field work, patience is a virtue.

While the cores will provide very detailed information, they only give information at a very specific place.  When comparing the size of the ice core (about 50 square cm) with the size of the ice sheet (about 10 million square km), it is apparent the ice core is a very small sample of the total.  The question becomes: how representative is an ice core of a larger area?   The radar surveys help us address this issue and extend the reach of the ice cores.

Zoe Courville logging an ice core. Photo: Stein Tronstad.

Radar surveys

We used five different radars this season (Diaries Dec 31, Jan 12, Jan 15), which image the internal layers of the ice sheet.  The high-frequency radars image the upper 20 – 100 metres of the ice sheet, while Kirsty’s low-frequency radar images all the way to the base of the ice.  Ideally, the UAV would have also mapped internal layers using the on-board radar system, but owing to some unexpected complications, this was not possible.  The layers revealed by these systems are essentially horizons of constant age, and are used to determine how the accumulation rate varies along the traverse route.  In areas with relatively low accumulation rate, these layers are closer to the surface.  In areas with relatively high accumulation rate, the layers are buried deeper.  The ice core data serves as calibration points for the radar layering, and provides the ages for the near-surface layers detected by the radars.  The radar data allows us to extend the ice core data from point measurements into data along the lines covered by the radars.

Anna Sinisalo at work behind her radar screens on board "Sembla".  Photo: Stein Tronstad.

Satellite data

Satellite data allows us to further extend the footprint of the ice cores.  Since the mid-1970s, satellites have imaged East Antarctica at a variety of wavelengths, but without detailed calibration, it is difficult to understand how to interpret these images.  Zoe has been working on measuring the physical properties of the upper 2 metres of the snow in her snow pits (Diaries Jan 16, Feb 9; e.g. grain size, permeability, thermal conductivity, density), and will conduct similar measurements on some of the ice cores.  These measurements will make it possible to determine exactly what has been recorded in satellite images.  Information on the physical properties, coupled with the ice core data, will make it possible to better understand the changes recorded by satellites over the past 30 years, and will extend the reach of our analyses to cover the entire region.

Thermistor strings

So while the radar data and a combination of satellite and physical properties data allow us to extend the results of the ice core analyses over a wider area, we also made use of the holes produced by collecting the deep ice cores.  Ted has installed two thermistor strings (26 Jan) to directly measure the ice temperature in the deepest core holes.  The temperature on the ice sheet surface changes with the weather, but the temperature deeper in the ice sheet only changes very slowly as the climate changes.  At 90m depth, the ice temperature is determined by the average temperature over the past 30-50 years.  By recording this temperature through time (and these stations should be continuously operational for 3-5 years) we can determine how the surface temperature has changed through time.  Though not as detailed as a record from a weather station, since there are no weather stations in this part of the continent, Ted’s thermistor measurements are as close as we can come to measuring surface temperature changes directly.

Recovery Lakes

Taken together, the radar data, snow pit studies, ice core analyses, and satellite data will provide a much better understanding of how climate is changing in this part of Antarctica.  Our route this season also provided an opportunity to explore the Recovery Lakes region (Jan 11), an area last studied during a traverse in the 1965-66 field season.  As we have read, this area is marked by a series of lakes beneath the ice sheet which lie at the head of the Recovery Ice Stream, one of the largest glaciers draining East Antarctica.  The lakes were first discovered via satellite in 2006.  There are four well-identified subglacial lakes in this area, and several other potential lakes (Jan 27).  The lakes range in extent from 600 sq. km to about 1500 sq. km, making these the largest subglacial lakes in Antarctica, aside from Lake Vostok.

Using our radar systems and high-precision gravity and GPS measurements, we mapped the ice thickness, internal layering, surface topography, and gravity variation along our traverse route and along several shorter side traverses over the lakes.  These measurements detail the size and shape of the lakes, and provide information about the water depth, as well as how the ice flows over the lakes.  Although the lakes were first discovered by satellite imagery, ground-based surveys are the best way to determine the lake geometry, and the ice flow characteristics.  We collected over 800 km of radar data along our side traverses, installed two high precisions GPS stations, and conducted high-precision GPS surveys of the surface topography along our routes.  The low-frequency radar has revealed that two of the lakes are actually connected, the average ice thickness over the lakes is between 3400 and 3500m, while the ice thickness over the lake margins and grounded parts of the ice sheet is typically less than 3000m.  The high-frequency radar surveys have shown that there are significant differences in accumulation rate across the lake margins, and that there are several areas with virtually no accumulation (so-called glaze areas).  The gravity data (Jan 5) will take more time to fully process, but initial results suggest water depth in excess of 100m.

We have had a very productive, very busy season, and as we arrive at Troll Station tomorrow, we can be justifiably proud of our work here.  By the time the project ends in 2011, we will have made great progress in understanding how this part of Antarctica fits into the larger climate in the southern hemisphere, how the climate here has changed in the past, and how Dronning Maud Land may change in the future.

Location: Hellehallet, 71º 46’ S, 5º 20’ E, 300 metres a.s.l.
Weather: Clear, -15 C, wind 18 kts

Siste sesongen I thought I would lære some basic Norsk – but jeg gjorde det ikke.  I did watch the entire Norwegian crew bedre their English 10 fold!  This past summer I decided to try. I found a bad book that had no audio.  I got nowhere, ingensteder.  While emailing back and forth planning the food,  Einar would often write a line or two in Norsk for me.  But I had no way to translate.  I am trying more this trip to listen and understand.  So – I write part of this daily diary-blog entry in Norsk.  Please forgive my enkle skills and vocabulary.

Duty List – Chore list – Oppgaveliste

Everyone on this trip has a very presis job – and then litt mer.  To maintain the camp there is a list of daily oppgaver to be done and we all pitch in.  As a group we decided early on that 2 people each day could handle it; the primary tasks being: cooking the 3 måltider and dishes, making water, cleaning the common areas, and often some restocking of supplies.  Science stops and driving days tend to be different on how and when – what needs to be done.

A typical day for two – en typisk dag for to

Ole and I are one of the 6 two person teams.  I lucked out cuz he likes to cook and han er god!  The night before we pull the dinner we will be making from the many choices in our inventory and let it thaw over night.  Last night was fish night – (twice a week) – we pulled 17 fillets, grabbed some Annies Mac-n-Cheese (Zoe’s favorite) and for the veggies I quite like peas (we added a few carrots for Ole’s kids cuz they like a colorful plate!)

Breakfast – frokost

I like to get up early so I lay out the breakfast things – cold cereal, make the juice and milk, grind nok beans for 3 pots of kaffe, brød, fresh yogurt and frozen berries, sometimes there is smoked salmon and or eggs to scramble.  Seems many have come up with some specialties: Kirsty makes great rice pudding, Anna makes fresh bread, Stein makes really good porridge, when time allows I make waffles.  Some folks specialty is doing the dishes.

The bathroom and the water – badet og vannet

After breakfast is cleaned up badet in the sleeping module gets a scrub down. Ole even takes to hoover over and støvsuge the hall sometimes!  The water consumption for 12 is kjempestor!! and melting is an ongoing process all day, every day.  The stainless steel melters are constantly working. Large blocks of snow are kept piled on the decks and stand ready . Timing is important because the snøsmelter provides the hot water.  So they must be filled directly after dishes to have time to melt and get hot før the next round of dishes (or shower).  We also have some 25 liter drink water jugs that we use for the cold water.  Believe it or not, the cold water is difficult. Vanskelig!  Much of the water from the snow melters is too warm or even hot – so the water jugs sit outside for a while to cool.  We also have melters on two of the vehicles (heated by the engine coolant), so while driving we are making water and then tar vannet ut when we stop for camp.

And then some more – og så litt til

The day finishes with the rubbish, recycling what we can; dishes, water, and restocking butter, cheese, juice etc for the next day.

Clothes get dirty in Antarctica too!  Photo: Stein Tronstad.

Location: Fimbulisen (ice shelf), 70º 06’ S, 5º 19’ E, 17 metres a.s.l.
Weather: Cloudy, -11 C, wind 14 kts

“Ivan Papanin” is a large, ice-breaking freighter of Murmansk, Russia.  During this Antarctic summer it is employed by the “DROMSHIP” network to shuttle cargo between the research stations in Dronning Maud Land and Cape Town.  Early this morning it arrived at Fimbulisen from Atkabukta (Bay), near the German Neumayer Station, and tonight it will return there to take on board more cargo, then proceed to Cape Town.

The loading was painless. Most of our cargo was preloaded into shipping containers, and went on board with a few crane lifts.  Along with us at “the quay” were Trond, Johan and Kai from Troll Station, who have come down to receive supplies for the station and to ship waste and other cargo out to South Africa or back to Norway.  They are running a more serious transport business than we are; with large Prinoth snow groomers pulling up to five container sledges each.

Usually the scene here at the unloading site is quite lively during the summer season, with Adelie penguins literally invading the camp.  Their natural curiosity attracts them to anything unusual, and to human activity in particular.  We are supposed to leave the wildlife here alone – but what can we do when the wildlife doesn’t want to leave us alone?  So we watch them just as keenly as they seem to be watching us; it is hard not to be charmed by these inquisitive and busy birds. 

We are, however, at the tail of their season, and the birds are leaving the coast.  Tomorrow all will be quiet at Fimbulisen.  The ship will have put to sea, the birds will be heading for the drift ice, and we will be on our way inland to Troll Station.

A lone Adelie penguin supervises the loading of “Ivan Papanin”.  Photo: Stein Tronstad/NPI

Trond Løvdal’s freight train crossing the ice shelf at dusk.  Photo: Stein Tronstad/NPI

Location: Fimbulisen, 70º 40’ S, 5º 9’ E, 70 metres a.s.l.
Weather: All clear, -16 C, wind 8 kts

Troll Station has its “port” on the Fimbulisen ice shelf 300 km north of the station itself, and the transport route between the station and the ship unloading site crosses the grounding line.  This is where the inland ice sheet meets the sea and transitions to a floating ice sheet.  The area is heavily crevassed, and over the years a lot of work has been put in to create a safe crossing.  A route through the area was found by an initial helicopter survey some 20 years ago, recent crevasse radar surveys have been carried out to check the size and development of crevasses, and snow bridges have been constructed and maintained.  But the ice moves seaward by some 50 metres per year, and the area is constantly changing.

Since we do have a crevasse detecting radar along (see the diary for December 31), three of us stopped for a couple of days in this “hinging zone” while the rest of the team continued down to the ice edge to meet the ship.  The route across the grounding line was manually surveyed and marked before the summer season, but given the opportunity we wanted to do a radar verification of the crevasse pattern and the snow bridges.  Thus we spent those two days in the area, driving the crevasse radar up and down along and around the track.

It has been a snowy summer, and currently the hinging zone has a fairly thick cover of fresh snow.  Nevertheless, locating the crevasses with the radar is straightforward.  We could easily check that the crevasses are indeed where we expect them to be and nowhere else.  Usually it is also fairly easy to see the width of the crevasses on the radar screen.  But the tricky part is to see the structure and thickness of the snow bridges.  Are they thick and solid enough to carry a heavy vehicle and container sledges across the gap? 

Mostly they are, by a wide margin, but there are always reasons for doubt.  The crevasses have an abundance of natural features inside – irregular ceilings and walls, remains of old, collapsed snow bridges, huge snow mushrooms blooming right off the interior walls, stalactites suspended from the ceiling, gaps and abysses of all shapes. Some of the constructed snow bridges have been undermined by snow collapsing deep down, and some of them have substantial gaps forming between the filled-in snow and the crevasse walls, as the ice is always on the move.All of this tends to confuse the radar image and makes it difficult to interpret what we are seeing.  There is only one way around the problem: We have to open the crevasses to see their inside form, gauge their dimensions and thus verify what we see on the radar.

The effort is time-consuming, but has its rewards.  Descending into the eerie, blue stillness of a huge crevasse is an awe-inspiring experience.  The air is completely still, all sounds are muffled, and nothing can be heard from the surface.  The diversity of forms, a variety of surfaces of shapes, labyrinths of ice and snow, inch-size ice crystals, gaps and cracks leading down and away into darkness – it is a scenery that never ceases to fascinate and spellbind.  But above all: Crevasse anatomy is sheer fun!

Kirsty going for a walk in the crevasse we have come to know as “H8”.  Photo: Stein Tronstad/NPI

Location: Fimbulisen, 70º 06’ S, 5º 19’ E, 17 metres a.s.l.
Weather: Partly cloudy, -11 C, wind 10 kts

After descending over 2500m in the last few days, we have driven north until we can drive north no further, at least not without getting wet.  We are at the edge of the Fimbul Ice Shelf, some 2400 km from South Pole.  The air is warmer (only -11 C!) and noticeably thicker down here at sea level.  The other big changes are the presence of birds (snow petrels, anatarctic petrels, skua gulls), penguins (one lonely Adelie penguin so far), ice bergs (broad, flat topped tabular ice bergs) and open water.  The scenery is very much a change from the mostly flat, and very white scenery of the polar plateau we have seen for the last 8 weeks.  Certainly the warmer weather is a welcome change.  Now that we are so far north, we have actual night here and stars (other than the sun) are visible for the first time since leaving Christchurch.

We will be here at the ice shelf edge for the next few days, repacking our cargo for shipment northwards.  In two days, we expect to meet the cargo ship Ivan Papanin, which will take our ice cores, cargo and waste farther north to Cape Town, South Africa.  The current schedule calls for loading the ship on 18 Feb, which gives us two days to pack and label everything.  It will be a busy time here before we are ready.  In the meantime, we find moments to enjoy the scenery, and the warmer weather.

This stop represents the conclusion of the science program.  Anna and I have been busy disassembling our radars, and Kirsty has already packed the low-frequency radar away.  We need to send as much as possible north on the ship, as the only alternative is to hand-carry the last few items on the flight from Troll Station in a week's time.  The flight will be quite crowded, as both the traverse party as well as the entire summer crew from Troll Station will be heading north on the same flight.  We are closer to a successful completion of our season, but not quite there yet.  Soon ...

Dark nights, icebergs, open water...  Photo: Ole Tveiten

Location: Hellehallet, 71º 02’ S, 4º 49’ E, 600 metres a.s.l.
Weather: Crystal clear, -16 C, wind 12 kts

Ice, the ice we are all familiar with in our drinks and on our sidewalks is a fascinating material.  I know I get funny looks when I tell people I study snow and ice. (“Don’t we know all there is to know about snow?” is one actual comment I’ve heard).  Ice though, is a unique material that exists very close to its melting temperature.  It is perilously close to becoming water!  Just a few degrees away, and it will become a liquid—much unlike the chair you are sitting in or the computer you are using.  That makes ice a fairly unstable solid. 

Here in Antarctica, under the ice sheet, it acts almost like a liquid itself, flowing out to the oceans, morphing and changing.  When snow falls here, it doesn’t melt due to the cold temperatures, but it does start changing (metamorphosing) immediately.  Pointed parts of snowflakes sublimate to make rounder grains, and small snow grains sublimate away and condense to make larger grains.   In my pits, I can see evidence of long periods of growth in low accumulation areas as large crystals with facets, which have grown into their shapes over time.  The upper 60 to 100m or so of an ice sheet is actually made up of snow, where air can freely move between snow grains.  As more and more snow accumulates on the ice sheet, the weight of the snow eventually starts to compress the layers underneath into ice, with individual air bubbles closed off from one another.  The depth that the transition from snow to ice occurs changes from location to location due to differences in temperature and the amount of snow falling each year, but it doesn’t occur usually until 60 to 100 meters depth.

The change of the material, from porous snow to solid ice, is part of the challenge that faces the driller.  In the upper few meters, the snow tends to fall apart.  Once you get into ice, you hit changing conditions that can go from hard and solid to brittle and fragile.  The driller has a host of options to come up with the best core.  To start with, the head of the drill that does all the cutting is equipped with two critical components, the cutters and the core dogs.   The cutters are the sharp, razor sharp, teeth that you find at the end of the drill.  They spin around and cut the ice.  The cutters come in a variety of widths, and angles, which can be changed to help accommodate the properties of the snow or ice being drilled.  The core dogs, sitting inside the core barrel, are spring-loaded hook-type teeth that catch the core once it is drilled.  The core dogs help break the core as well, which is usually accomplished with a short, quick, hard jerk to snap the bottom of the core just drilled so that it can be pulled out of the hole.  In softer snow, a collet, a collection of delicate teeth arranged in a ring, is sometimes used in place of the core dogs as a more gentle way of getting the core out.  The collet is needed in snow that is soft enough that the core dogs don’t have anything to grab onto.  The driller can also control the speed of the drill turning in the ice.

For the first part of the traverse we struggled with what I have affectionately been calling “devil snow.”  The snow is not at all sintered together, but instead a loose collection of large crystals, much like sugar.  We’ve been having problems getting the core dogs to grab onto any cores we’ve drilled, and have tried all sorts of different tricks – loosening the springs on the core dogs, using the collet, trying cutters with different widths and angles. What usually happens is we get either a barrel full of loose snow that falls apart when we push it out of the barrel, or a core left in the hole that the core dogs haven’t managed to grab onto.  At one site, we started and abandoned 10 different holes!  What did seem to work was to drill down through the soft stuff until we found a hard layer, which usually took some luck.  We ended up with several “hangers,” which is where the core is hanging out of the bottom of the drill, usually with core dogs scraping up the side of the core through soft layers until they hit one of the harder layers.  Some of our cores were hanging on to mere centimetres of harder snow, with up to 40 centimetres hanging out the end. 

As frustrating as it has been trying to core, it is interesting to ponder what the climate has been doing here to create the devil snow we have been struggling with!

An ice core stuck in the bottom of the hole.  Photo: Zoe Courville/NPI

Location: Tønnesenbreen, 71º 58’ S, 3º 32’ E, 1710 metres a.s.l.
Weather: Clear, -25 C, wind 6 kts

I was the last to see them. Sat in the Rock for our 24 hour drive out of the storm, my windows were completely and thickly iced over. I stepped out into brilliant sunshine, a gentle breeze and large rocky outcrops interrupting my line of sight. The large dark brown intrusions into our world were a magnet to the eye. The Rock had found it’s own.

The drive down to the lowlands the next morning was spectacular. The crystal clear air and lack of reference points makes it very difficult to comprehend scale, and I feel sure I would have been doubly impressed had I seen the small dot of a climber scaling the walls of stone. The light jovial mood only increased as we were welcomed back to civilization by the Troll crew with the cake of all cakes.

The polar plateau is a fantastic world of variety where one learns to appreciate the small and the subtle, where we are the largest and yet the smallest parts. We have all come to feel a part of this, enjoying it’s treasures to the full. The mountains are a welcoming sight, but I wonder if it’s more because they signify the nearing of the end, a return to relative normality.

Britt, the chef at Troll Station, greeted us with this wonderful cake.

The Rock finds it’s own.  Photo: Stein Tronstad/NPI

Location: Terningskarvet, 72º 15’ S, 2º 53’ E, 2400 metres a.s.l.
Weather: Clear, -24 C, wind 4 kts

Actually, the first major accomplishment was making it to Site 7; the second was that we arrived here in time to conduct a significant amount of science.  When we left South Pole, we were already three days behind schedule.  We planned for six days at Site 7, but were aware than any delays would cut into our program planned for this site.  Over the next seven weeks, we saved time when possible, and gained a half-day here, and another half-day there.  As we pulled into Site 7, we had saved enough time to be able to spend five full days here.

This allowed us enough time to accomplished nearly all of our goals here.  The deep drilling crew recovered an 80 metre core for chemical analysis before giving the hole to Zoe for video logging, and finally to Ted and Andreas to install a thermistor string to measure the ice temperature.  The deep drilling team then moved over and collected at 25m core for analysis of the physical properties (such as the grain size, density and permeability for the firn) before spending the last day taking the entire drill apart and packing it away for shipment back to the United States.

Zoe dug yet another 2m snow pit (well, 2.25m actually) and spent two days making a variety of measurements, before helping Tom collect the last of the hand-drilled firn cores.  Tom and Anna also took advantage of the opportunity to complete a shallow radar survey around the drill site, to learn more about how the snow accumulation and surface topography vary locally.  The radar crew also spent an afternoon backtracking about 25km to further investigate an interesting subglacial mountain.  Everyone spent time packing boxes, and getting ready for the last stretch of driving down to meet the cargo ship at the ice shelf edge.  Of course, the science never stops, and we will be collecting radar and GPS data as we make our way north.

The stop at Site 7 ended with the gale and technical delay we wrote about in yesterday’s blog, but today – after having driven through all of last night – we are back on schedule again. We have descended to 2400 metres above sea level, the gale has abated, and the temperature has risen to a balmy -24 C.  All of the high plateau is in fact behind us, and best of all: we have mountains around us again – a feast for the eyes after more than two months of utter level whiteness!

Tom drilling a short core with the hand auger one of the balmier days at Site 7.  Photo: Stein Tronstad/NPI

Location: ”NUS08-7”, 74º 07’ S, 1º 36’ E, 2700 metres a.s.l.
Weather: Clear, -42 C, wind 28 kts

We have had the somewhat dubious pleasure of facing that beast today.  For those of us working outside, the term “windchill” took on a very concrete meaning. This is a calculated temperature figure, intended to show the combined effect of temperature and wind on exposed skin.  More wind means that more cold air passes by the skin, and thus more body heat is transported away than when the air is still. The windchill figure aims to say what air temperature the cooling effect would correspond to if experienced on a day with no wind.   Today the air temperature of -42 C and the gale force wind combined to give a windchill of -65 C, meaning that the conditions were just as chilling as a day with -65 C (-86 F) and no wind. In such conditions any exposed skin will be frostbitten within a few minutes, or even seconds.  Full coverage of all body parts, even the face, is required when working outside.

The vehicles were also affected quite a bit.  With the wind came persistent snowdrift, and the gale pushed the snow into any open gap, crack and crevice – including the air intakes and exhaust pipes of the Webasto heaters. Being unable to preheat the engines in the morning, we had to employ industrial heaters and wind breaks to get anywhere.  Only after 8 hours of work did we have all four vehicles up and running, and thus our departure from science site 7 was delayed by almost a full day.  (The science summary from site 7 was also affected, but you will have it tomorrow.)

To make up for lost time and to avoid stopping the engines in this unabated gale, we have been driving through the night till Thursday.  It was the first on the traverse that felt like a real night – not very dark, as the sun was barely below the horizon for four hours, but rather a palette of pale pastels, with its own dreamlike splendour.  We have seen the winter cloak of the ice cap, and it is time for us to go down.

Engine revival in windchill -65.  Photo: Stein Tronstad/NPI

Location: ”NUS08-7”, 74º 07’ S, 1º 36’ E, 2700 metres a.s.l.
Weather: Mostly clear, -33 C, wind 13 kts

We are now in the upper reaches of a massive, fast-flowing outlet glacier for the East Antarctic Ice Sheet, Jutulstraumen Glacier – the Jutul’s stream.  It is named after Jutulen, a character from the Norwegian folk tales. Jutulen was a troll-like figure who could take on the appearance of a human being and ride his sledge through the skies.  He used to live inside a mountain, entering through a huge gate in the mountain face.

Jutulstraumen parallels this, originating behind the mountain ranges, and flowing down to the lowlands through a narrow gateway between the Fimbulheimen mountains.  Down there it picks up speed – up to 4 metres per day near the coast – and it is covered with huge crevasses. But up here, the ice flow is slow enough that the ice bends, without breaking, in response to variations in flow speed – thus sparing us any concerns of crevasses.

We are, however, well into the drainage basin of the ice stream, on the downhill side of an ice divide.  The ice divides of Antarctica mark boundaries of both ice flow direction and storm tracks. Thus our Site 7 research stop has significantly different snow. Here, the climate is much snowier (although still bone-dry by most standards), and there are occasional weather systems that come in from the ocean out of the northwest (with northerly, up-slope flow, and therefore more precipitation). The snow is firmer, more layered, and easier to dig and core, according to our sampling teams.

We are also in a faster ice flow area, and as a consequence there is greater local topography. This came as a bit of a surprise, since topography is still almost imperceptible if you are just standing and looking at the horizon. But as our skiers glided off for their daily exercise, they noted that the camp disappeared behind them within just a few hundred yards, dipping behind a local rise.

Jutulstraumen flows out to a large ice shelf, the Fimbul Ice Shelf (Fimbulisen), and eventually forms the Trolltunga ice tongue.  Every few decades this outflow breaks off as one of the large tabular icebergs Antarctica produces. We will be driving onto Fimbulisen in the next week – more on how it behaves, and looks, then.  We’re looking forward to our first new sightings of wildlife (other than ourselves!).

Our work at science site 7 (“NUS08-7”) was completed today, and tomorrow we will tell you more about what we have been up to in Jutulstraumen’s catchment.

Location: ”NUS08-7”, 74º 7’ S, 1º 36’ E, 2700 metres a.s.l.
Weather: Overcast, light snowfall, -28 C, wind 14 kts

At each stop, the devil snow that we had been dealing with at the Recovery Lakes—the sugar snow that fell apart as it left the shovel and thwarted several drilling attempts—gave way to more “normal” snow.  This is happy news for Lou especially, as it means that the drilling will hopefully go more smoothly in snow that will stay together.  In my pit, it means that the snow is not so sugary and easier to cut into blocks.  The improvement in snow conditions is due to the increase in snow accumulation as we leave the lake area.   While the sugar snow is not as problematic, the MOAHLs (the Mother of All Hard Layers) are still here, and even harder and tougher than in the lakes area. 

One such hard layer I found 2 m in the pit resisted any attempt I made at sampling it.  The cutters and the snow saws I had could hardly make a dent in the layer, let alone cut all the way through it.  At Lou’s suggestion, I used one of the hand augers to drill through the 5 cm section, and that finally worked, given the sharp cutters on the drill head.  I’ve decided to call this layer the Chuck Norris layer—since Chuck Norris doesn’t leave messages, he leaves warnings.

I’ve been using a near infrared (NIR) camera that helps me to document the layering in the pit.  The NIR detector in the camera is sensitive to differences in grain sizes in the pit, and so the layering is apparent.   The pictures help document the changing conditions as we move towards the coast. 

NIR photos taken from the Recovery Lakes area, left, and this site.  Darker shades generally mean larger snow grains.  The arrows mark two thick (5 cm) layers made up of loose sugar on the left.   On the right, the arrow marks a more normal hoar layer, large grained layers that form in summer seasons from vapour movement in the snow pack.  Photos: Zoe Courville

Location: ”NUS08-7”, 74º 7’ S, 1º 36’ E, 2700 metres a.s.l.
Weather: All clear, -24/-37 C, wind 3 kts

With the altitude follows low air pressure and a relative lack of oxygen, giving the engines a significant reduction in power output and less efficient combustion.  There are no straightforward solutions to this problem.  Modern diesel engines are computerized, and in this case the computer’s response to the lack of oxygen is to reduce the amount of fuel injected.  The engine output spirals down, precisely when we need it to go up.  The solution has been to reprogram the computers and to short-circuit the air pressure sensor, making the engines “believe” that they are running at sea level.

The cold is a more comprehensive problem, affecting virtually everything mechanical.  Meltwater running off hot panels, condensation in fuel tanks or hoses, or any other water seeping into inconvenient places – all of it will freeze and stop parts from running or liquids or air from passing.  Batteries will also freeze if not properly maintained.  A fully charged vehicle battery can survive a solid –70º C; but if completely discharged it will freeze up already at –10º C.  Fuel, oil and lubricants loose viscosity and get thicker, metal and plastic components get brittle, materials contract, fittings loosen, and vibrations increase.  In normal temperatures electrical cords will coil easily, below -30 C they get rigid – and instead of a coil we may end up with a pile of broken segments.

Almost any mechanical part will break more easily in the cold, everything is harder to move or get moving, and any engine or Webasto heater will be difficult of impossible to start without advance preparations.  The vehicle wheels pose a good example: At +20º C the wheel will roll freely on its bearings, and a light touch will set it moving.  At –40º C we will have to apply a force of about 15 kg to be able to turn the wheel at all.  Our TL-6 vehicles have 24 wheels each, so at these temperatures it takes a lot of power just to get the wheels rolling – let alone move the vehicle.

How are we dealing with all this?  First of all, the vehicles, generators and other machinery is specially prepared.  All engines have electric block heaters and fuel-burning Webasto heaters.  Separate heaters are mounted on the fuel filters, the hydraulic and engine oil systems.  Some hydraulic cylinders are also separately heated.  Cords are made of special materials, and coolant liquids are chemically altered to lower the freezing point.

Secondly, we have it in our daily routines to be prepared. A generator is always kept running throughout the night, delivering electricity to heaters and battery chargers. When we start driving in the morning, it is never just a matter of turning the key and getting off.  The Webasto engine heaters are usually started at 6 am and allowed to run for an hour before we start the engines themselves.  After another hour of idling, the engines are usually warm enough to start driving – but even then it’s done cautiously.  We start in 1st gear, go to 2nd after a few minutes, and keep going very slowly to make sure all systems have a good working temperature before we finally increase to normal driving speed after about 20 minutes.  Thus it takes us nearly 2,5 hours to get the vehicles going at full speed.

The key is to maintain good margins and always take precautions.  Fuel tanks are topped up before nightfall, to avoid humid air and water condensation inside them.  Batteries are always kept fully charged.  Electrical cables are always handled very carefully, and never when connected to power.  Heat and energy conservation is always on our minds, and thus we are still going strong, at 2700 meters of altitude and with night temperatures dropping well below -40º C.

Andreas with a cord that probably shouldn’t be coiled right now.  Photo: Stein Tronstad/NPI

Location: 74º 7’ S, 1º 36’ E
Weather: All clear, -31 C, wind 12 kts

The station was built by the German polar and oceanographic institute, the Alfred Wegener Institut (AWI), in 2001, and named after the geophysicist Heinz Kohnen (1938-1997). The station is constructed of containers from the previous Filchner Station; eleven of them put together on an elevated platform, and with auxiliary modules in the vicinity, among them an automatic installation for weather and air quality monitoring.  As Antarctic stations go, it is a humble structure, but it was intended for summer operations only, and accommodates up to 20 persons in relative comfort.

The key feature of the station remains invisible to the unsuspecting visitor – a 66 meters long, 6 meters deep and 5 meters wide trench, excavated in the snow and covered by a wooden roof and a thin layer of surface snow.  The trench accommodated the deep drilling of the European Project for Ice Coring in Antarctica (EPICA), which was the primary purpose of the station.

The ice core drilling operation started during the 2001/2002 season and was completed in 2006 when bedrock was hit at a depth of 2774 meters.  The deep core is one of two retrieved by EPICA, the other one being the Dome C (Concordia) core in the Indian Ocean sector of East Antarctica.  The Dome C core is the longest ice core ever retrieved, providing a history of detailed climate and atmospheric changes over the last 900,000 years.  The Kohnen core is shorter, but it is taken in an area with higher snow accumulation, thus allowing the reconstruction of a  high resolution climate record for the past 160,000 years (the upper part of the core).  Kohnen sits in an area predominantly influenced by Atlantic air masses, so the core from this location allows for more direct comparison with the ice core records from central Greenland. Key scientific objectives have been to study:

• the occurrence of rapid climate changes in the past, and how these have been triggered
• if the climate of the last 10.000 years has been exceptional in its stability
• how global climate changes are linked between the northern and southern hemispheres
• the contribution of greenhouse gases to the glacial-interglacial temperature changes

More information can be found on the EPICA website.

With the EPICA drilling concluded, Kohnen Station has not been manned this season, and future plans are uncertain. If a decision is taken to discontinue operations on this location, the entire station will be dismantled and removed from the site.  If so, the only traces of any human presence at 75º S, 0º E will, for a few more years, be a couple of low hills on the snow surface.  But the data and knowledge that scientists have gathered here will be with us indefinitely.

On our part, we have moved on another 110 km today to a position known as NUS08-7, our final science stop. We will spend five days here to collect even more data about the high plateau and the climates of the past.

Lou and Einar inspect the jacking system of Kohnen Station.  Photo: Stein Tronstad/NPI
 

Location: Kohnen Station, 75º 0’ S, 0º 0’ E
Weather: All clear, -34 C, wind 12 kts

Hard to believe, but at about 1500 this afternoon, small black dots started appearing on the horizon.  Over the next hour, these dots grew larger and proved to be Kohnen Station.  We parked at 1600 this afternoon, after 7.5 days and 780 km of travelling.  This is first outpost we have seen since leaving South Pole station some 43 days ago.  It is comforting in some way to know that other people have been here.  In tomorrow's post, Stein will tell us all about the science that lead to the establishment and maintenance of the station.

We have come to the station to recover a fuel cache which was left for us last season.  The station map we received last summer shows the location of our 25 drums of fuel, and these were apparent as we drove in.  This afternoon, the technical group is collecting and loading the drums on to our sledges, and preparing for the last stretch.  At last check, we have 900 kilometres yet to go to Troll Station (via Site 7 and the ice shelf offloading site).  Although we do have some margin, these 25 drums will insure that we arrive at Troll in good style, with some fuel to spare.  While we are here, Kirsty will do a low frequency radar survey, and Zoe will collect a short firn core.  As long as we are here, we can't resist doing some science. 

At the moment, all is quiet here at Kohnen, and there are no other people here; typically the station is only staffed During the summer season.  However, there will be a flight tomorrow (coincidentally enough) to service the weather station here, and do the final preparations for the upcoming winter.  We may or may not still be here when the flight arrives, as we hope to drive on to our last science stop (Site 7) tomorrow, some 110 kilometers from here.

The traverse team in front of Kohnen Station. Photo: Stein Tronstad/NPI