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The Aurora Programme saga: Part 3.

Into the field

in Antarctica , Friday, January 17, 2014

This article is the third in a 4-part series about the Aurora Programme, a privately-funded expedition to Antarctic which took place in the 1991-1992 austral summer/autumn. Read Part 1 here, and Part 2 here.

The Aurora’s hold was pretty full. Apart from the science and logistics equipment, there was a full prefabricated base to unload, and move up to above the ice cliffs. This is what the helicopter was mainly for - a sky crane. With a combination of very skilful flying and good teamwork, the unloading went well.

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Monica asks if anybody’s seen a tent

Once the unloading had been done, the various groups dispersed. A building team remained to construct the four pre-fabricated huts that would form the base.  The geology team set off for the Shackleton Mountains region. Another team set off to survey glacier grounding lines on the East coast of the Filchner Ice Shelf.  The Pole team started working on surveying landing sites and laying refuelling depots for the Twin Otter to reach and return from South Pole, since the Americans at Amundsen-Scott weren’t going to refuel it. And we were flown out to the Filchner Ice Shelf.

Me jeff and otter

Myself, one of the GLACE crew, and Jeff, raring to go.

In order to do our validation work, we needed to find a location under the ERS-1 satellite track, as flat as possible, and free of obstructions or significant topography within 50km or so. The middle of an Antarctic ice shelf was therefore the ideal location, provided there were no crevasses. There wasn’t a huge amount of time to choose a site, so we were quite fortunate to find a suitable spot more or less in the middle of the Ice Shelf, at S80° 06´, W41° 53´, which we would later dub “Snowhenge”. We were equipped with three tents, two excellent Yamaha snowmobiles, a UHF radio to keep in touch with the Aurora (and as it turned out the Australian Flying Doctor …), and plenty of supplies. Although the pyramid tents were Norwegian-spec single skin design, rather than the seemingly more robust, but much heavier British twin layer version, they were fine. Generally speaking the quality of equipment and supplies matched or exceeded British Antarctic Survey standards. The only problem was this: it was now mid-January, and the sun was sinking towards the horizon. By this point, most deep-field parties such as ours were wrapping up their work and preparing to be flown back North. We had not begun, and yet we’d planned at least a month’s fieldwork.

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The Filchner Ice Shelf camp

Our work schedule from then on was to be governed by the heavens, or to be more prosaic, the orbital paths of the ERS-1 satellite and those of the GPS constellation.  ERS-1 would pass directly overhead every 3 days. At these times, Jeff needed to get scatterometer data. The GPS constellation was still in its infancy in 1991, and we only had sufficient coverage (3 satellites visible with reasonable separation) for 4 3-hour periods every day. Since there were only 3 of us, it soon became clear that we were going to have to split the work between us. The scatterometer was quite cumbersome, and Jeff really needed Peter’s assistance to move it. The GPS surveying, on the other hand, could technically be done by one person, even if this was an absolute no-no for Antarctic fieldwork. Pragmatically, there was no other choice. But we tried to take what precautions we could. First, we surveyed a 40 km route southwards along the ERS-1 orbital path, taking two snowmobiles and carefully checking for crevasses. This established a path I could later follow alone.  We also checked out several parallel routes offset 10km east and west. This determined a safety area in which we could build up our ground survey.  To the east we did discover some crevasses, but they were large, open, not in our way, and easy to spot given good conditions.  A more crevassed area was found to the north west of Snowhenge, in the direction of Berkner Island, so we decided to position our survey area mainly to the south of our camp.

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Peter, David & Jeff, and scatterometer: furthest South official photo.

We then settled into a routine. Since Jeff & I were sharing a tent, and Peter was enjoying his polar superhero fantasies alone, it ended up with one or the other of us clambering out of the tent at some ungodly hour trying not to wake up the other one. The theory of the GPS work was fairly straightforward. One antenna was strapped securely to a snowmobile, and a receiver was hooked up to it.  The receiver sat more in less in my lap. The second antenna and receiver were set up at the camp. The idea was to use the differential method, recording two signals and post-processing to remove errors in the track recorded by the moving receiver (you don’t have to do that these days - young people today have it too damned easy!).  In addition, to help things along, it was generally a good idea to stop every kilometre or so to let the mobile receiver get a better fix. And, based on the advice on the NERC experts, it was also a good idea to switch off all possible sources of interference, including the snowmobile engine.  This was not something I felt all that happy about, especially when alone, at 3am, 40km from camp, at around -25C, and with no radio contact. Actually, there was no way on Earth I would have done that with a BAS-issue Bombardier Skiddoo snowmobile, but the Yamaha was much more confidence inspiring. And we had an agreement that if I didn’t turn up by a certain deadline Peter would come to look for me, following my tracks (there was a bit of a flaw in that plan, considering that Filchner Ice Shelf is quite a windy place, and that wind and whiteouts can rapidly conceal snowmobile tracks), and I had a survival pack. Well, it all turned out fine, but yeah, it was bloody stupid. But we’d come all that way and I wanted my data.

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The GPS surveying set-up

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A long way from nowhere

Did I mention -25C ? Well, that was something that we hadn’t fully factored in. Probably, had we been backed up by a full national program logistics organisation, somebody might have pointed out that at such temperatures, batteries might not perform quite to optimum levels. The first sign I got of this was returning to camp on one of the first trips, and hearing a strange high pitched sound. This was actually not one of my team-mates snoring, but the second, reference Ashtech receiver using up it’s last few millivolts to emit a warning “battery-low” buzz rather than saving and securing it’s RAM data. This was, in my colourfully expressed opinion, a bit of a design flaw, and a sound I would come to dread. Essentially it meant that the post processing would be tricky, and in some cases impossible. Certainly, it couldn’t be done in the field with the primitive laptop software we had.

Ah yes, the laptops. At one point, we noticed that the laptop hooked up to our ARGUS weather station was showing remarkably steady weather conditions.  Temperature, wind speed, wind direction, humidity, none had changed for ages. At this point somebody noticed that the laptop’s liquid crystal display (this was 1991, remember) had frozen solid. Oh well. After it warmed up it was fine.

When not surveying in one way or another, we carried out some more traditional glaciology, digging snow pits to record melt horizons (which could be very significant for the ERS-1 radar altimeter echoes) and measuring 10m depth temperature profiles using a superbly hand crafted set of thermistor cables. These data, together with the weather station data, could be used in future to plug into out model of how the ERS-1 13.8 GHz radar waves interacted with and penetrated into the snow. On days when ERS-1 was not overflying us, Jeff used the scatterometer and associated equipment to measure physical properties of the snow which combine to reflect the radar signal.

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Jeff hard at work pushing the scatterometer and pulling the electronics sledge

And we put the snow blocks extracted from the snow pits to good use, building the structure which gave our camp - and this website - its name.

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GLACE Flight 999 approaches Snowhenge International Airport

Although things started out well, some snags were on the horizon. First of all, our generator broke down, and we were unable to recharge batteries, including our radio battery.
The glacier survey team turned up and brought us a new generator, but also requisitioned a large proportion of our fuel reserves, seriously restricting our GPS surveying. It seemed that in general there was insufficient fuel to satisfy all the fuel parties’ snowmobile needs. We were also running low on paraffin for heating and cooking. And the scatterometer suffered a broken diode, making it unusable. But the worst blow fell further south. 

While landing at a depot towards the south of the Ice Shelf, the Twin Otter grazed an unspotted crevasse and tipped slightly into it. It escaped with a damaged ski, which was extremely lucky in the circumstances, but there was no way to repair it. This was the final straw. The GLACE crew had no option but to fly all the way to Canada to get it fixed. This took several weeks (a Twin Otter’s top speed is about 120 knots), and during this time, our field party was effectively stranded.  We had insufficient fuel to travel overland to Blaenga, or indeed much anywhere, and we were well out of helicopter range. Fortunately nothing went wrong, and the Twin Otter eventually returned, bringing as a bonus a new diode for the scatterometer.  But by this time, a late field season had turned into an extremely late one.  Nevertheless, Monica wasn’t going to give up the Tent, and all efforts were focused on that.

Before, however, we were to be evacuated from Snowhenge to a location from which, if necessary, we could reach Blaenga under our own steam (and in Peter’s dreams). We still wanted to try to get a second dataset in a more plateau-like environment with undulating terrain, and we had selected a site on Coats Land, which we dubbed “Newhaven” - as it turned out craftily concealed in a hollow and invisible from a km or so away. We packed up Snowhenge, and the Twin Otter arrived to carry us to our new home in the hills. Soon after we arrived, a snowmobile party from Blaenga turned up, bringing Elisabeth and Axel to join us.

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Our new home at Newhaven

Meanwhile, the South Pole party had finally got going, delivered by the Twin Otter, to start the search for The Tent.  There are conflicting stories about what actually happened next. According to the South Pole log the ground-penetrating radar was never used. However, Jeff recalls that the team claimed to have used it and to have found a cavity in the snow close to the predicted location of the tent. Personally I’m skeptical, but either way, the Tent was not found.

Feb 16 1992: Monica with the marker tent set up at South Pole. Read the full story (scroll down to the 1991-92 section) at southpolestation.com

There’s also some contradiction about whether or not the US National Science Foundation supported the Tent search. Again according to that South Pole log they did, but my recollection from field radio chit-chat at the time was that there was some serious resistance in-situ - indeed, we had the impression they were practically hostile and refused to even allow the team to enter Amundsen-Scott base.

In fact, I’m sure there was a radio exchange something on these lines…

[Blaenga] "Blaenga, Blaenga Station calling Amundsen-Scott"
[A-S] "Who???"
[Blaenga] "Yeah, hi, er, look, we'll be dropping in tomorrow to pick up Amundsen's Tent"
[A-S] "Say again? What tent ?"
[Blaenga] "Amundsen's Tent.  He left it there in 1911"
[A-S]  er, Hold 5 …(static, unintelligible background chatter, laughter)…
[Blaenga] "Hello ? Amundsen-Scott? Do you read?"
[A-S] "Blaenga, yeah, um, you, er, know that it isn't here any more, right?"
Blaenga huts

Blaenga Base. Great location, ample parking, winter sports, suit nature lovers

Meanwhile at Newhaven things were getting a bit gloomy. It was now getting darker at night and quite chilly, and we had very little idea of what was going on, generally. The option of travelling to Blaenga by snowmobile was looking more likely, but we were not well equipped, or experienced, for such a journey. Conserving fuel also restricted our field work, and morale was declining.  I seem to recall that the scatterometer was either not working, or its frame had collapsed, but for my part I was able to do some basic GPS surveying. This time, rather than a long, along track grid, I settled for a cross-shaped survey centered on Newhaven. Elisabeth had her own work to do, digging pits for snow samples, and we took advantage of these to make more thermistor measurements. I do remember that we set up a hot shower tent, though. That was definitely a high point!

Transport

The complete Aurora Programme transport pool huddling in a snowstorm

Eventually we were airlifted out and back to the Aurora which had returned to the vicinity of Blaenga.  But this was not the end of the saga. Blaenga had been closed down for the winter, but Monica’s team was still as South Pole, and apparently were not making much progress. She was reluctant to leave, and with the weather closing in on the Aurora, emotions were rising and things were getting tense. And yet, this was the Antarctic, and it had a few gifts for us.  We were blessed with several days of gorgeous weather, stunning, endless sunsets, and the visit of a very chilled-out group of curious emperor penguins (and some of their Adelie friends). These days I’d have to pay $20,000 for an experience like that. But eventually, some vestige of common sense, and the combined pressure of the Aurora’s captain and the GLACE crew won over, and the Pole team were pulled out. The Twin Otter immediately set off North West in the direction of the British Rothera base in the Antarctic Peninsula. And the Aurora left almost as quickly.

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Some Emperor penguins come to inspect us

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The Aurora hurries off into a darkening Weddell Sea

The return journey was uneventful, once we had left the Weddell Sea, although we had a very strange encounter when the bridge watch reported seeing the conning tower of a submarine rapidly heading south into the Antarctic night. I volunteered for watch duties and spent most of my time on the bridge, hearing stories of the Lofoten Islands from the captain. We stopped off for a few days at Grytviken, in South Georgia, which was a pleasant surprise, before finally returning to warmer waters and summer in Uruguay. Relations with Monica remained tense, and she kept herself largely to her cabin. My own relationship with Monica became extremely strained, and was only more or less repaired as we finally went our separate ways some 4 weeks later at Paris airport.

Posted in category "Antarctica" on Friday, January 17, 2014 at 06:00 PM

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