Safe descent into the Eternal Ice

 

The Alfred Wegener Institute has been operating the Kohnen Station in Antarctica for more than 20 years. At the research station, a wide variety of studies are carried out in the fields of climate research, air chemistry, meteorology and the like. Scientists also drill ice cores here to investigate how climate conditions developed in the near, distant and very distant past. The examination of air trapped in deep-lying, old ice layers, for example, provides information about its composition in times long past - experts regard the ice cores obtained as a kind of "climate archive".

Since Kohnen Station can only be inhabited during the Arctic summer months from November to February, the rotating research teams move from the year-round base Neumayer Station III 750 km inland to an altitude of 2,892 m for several months to drill new boreholes or collect and evaluate other climate-relevant samples and data at Kohnen Station, which can hold up to 20 people.

The team around station manager Holger Schubert, who was to be there at the turn of the year 2021/22, had something special in their luggage: the material for a RINGSCAFF stair tower from Scafom-rux, which gave the manufacturer from Hagen, Germany the chance to realise what was, according to sales representative Maximilian Rux, its "southernmost project ever". And probably the coldest.

But first things first: After 14 days of quarantine in Cape Town, South Africa, followed by a flight to Neumayer Station III in Antarctica, the Kohnen crew of the 2021/22 season began preparing the traverse to the actual destination - "traverse" is the name given to the transport of cargo and equipment with the help of pistenbullys and sledges. However, this has nothing to do with husky romance, as each of these vehicles pulls several containers of up to 35 tonnes total weight.

The preparations for the 750 km journey to the inland ice were very speedy and concentrated, but the departure date had to be postponed again and again, because when a very strong depression with snowstorms and winds up to 130 km/h settled on the Weddell Sea area, it was not possible to start the traverse. After about two weeks of waiting, a small weather window finally appeared.

The nine-member team seized the opportunity and the convoy, consisting of 6 vehicles, each pulling 3 container sledges, set off. With driving snow and a visibility of about 25 metres, the conditions were far from ideal but, according to Holger Schubert, who was after all competing in his 21st Antarctic season: "Manageable." The long journey to Kohnen Station took 10 days. Already on the way, snow depth measurements were carried out on behalf of scientists. Snow samples and other investigations were also on the agenda.

The snow conditions coupled with the aforementioned 35-ton load that each Pistenbully had to pull made the journey extremely demanding. Getting stuck, pushing and digging out the trains again accompanied the mountain journey, which ultimately took them up to almost 3,000 m above sea level. On 2.12.2021, the convoy reached the Kohnen station and awoke it from its unmanned hibernation. The infrastructure was built and everything necessary for life was set up. The scientific research as well as the maintenance work on the drilling trench in which the drilling unit was housed, as well as on the station itself could be taken up - including the replacement of the aging station generator.

Immediately after the turn of the year, the RINGSCAFF stair tower project was tackled. It was to be used in the scientific centre of the facility: the aforementioned drilling trench. This was built a good twenty years ago. For this purpose, an approximately 70-metre-long trench (5.5 metres wide and 6 metres deep at the time) was cut out of the ice. Then a wooden roof was built over it and all the drilling equipment was put in there, always well protected from wind and weather. Wood and snow? Holger Schubert waves it off: "With humidity approaching zero, the snow doesn't bother the wood. No metal will rust in the dry Antarctic air either."

Over the years since its first deployment, the drilling trench has brought to light an ice core (in 1-metre-long pieces) of an impressive 2,774 metres in total length from the depths. The natural snow accumulation had made it necessary after 10 years to erect a second roof over the first to preserve the trench and ensure continued access to the borehole, which had continued to provide scientific data all these years. The snow was then removed from the lower roof and the roof was henceforth used as a false ceiling for stowing provisions and equipment.

The height (or rather depth) of the trench was now about 10 metres - 4 metres more than when it was originally created. In order to ensure safe access to the trench and borehole, it was decided to use a stair tower from Scafom-rux, which could be successively adjusted in height and which, with its simple handling and robust material design, ensured problem-free construction even in extreme sub-zero temperatures. To make the openings for the stair tower, the team cleared the snow from the roof, cut the roof open on both levels and supported it from below. An inspection and repair of the foundation was also carried out.

Now it was time to recall the skills learned months ago at the scaffolding manufacturer Scafom-rux in Hagen, 'zillions of kilometres away, and erect the first segment of the RINGSCAFF stair tower. The assembly of the modular scaffolding took place in the best weather conditions. In Antarctica this meant clear skies, little wind, outside temperatures (outside the trench) around -36° Celsius, inside the trench around -46° Celsius. Station manager Holger Schubert: "We avoided touching the steel with our bare hands and secured our colleagues. Since we had been at the station for a long time, we had got used to the temperatures and no longer needed the very thick overalls. This allowed us to move relatively freely."

For reasons of space, it was decided to set up outside. This meant that all the material did not first have to be brought down to the bottom of the trench and then work its way upwards in a relatively cramped space. After completion, the first segment of the stair tower was completely lowered into the shaft by means of a Pistenbully acting as a crane, after the concrete-hard snow walls had been corrected somewhat by means of chain saws. The first segment was then aligned and brought into the desired position. Then the tower was built up to the edge of the trench. After wedging the components in place, a very stable, safe and perfect access to the trench was obtained.

At the end of the season, the tower was dismantled before leaving the station, so that the roof could be closed again. This prevented the drifting snow of the coming winter from getting inside. In a coming season, a third roof will be installed to relieve the current roof. Then the stair tower will be further extended - to a provisional total height of about 14 metres.

Conclusion: Despite a difficult season dominated by bad weather, many scientific, logistical and technical projects were carried out and successfully completed at the station. And the fact that a stair tower, which under normal circumstances would be considered relatively unspectacular, can now do its useful service in the name of science in the eternal ice, naturally pleases the staff of the manufacturer immensely. Holger Schubert thanked Scafom-rux again personally in an email: "(...) for the material supplied and the friendly support. Many thanks also to all colleagues who carried out the scaffolding material training with me. They put a lot of effort and patience into it. The advice and tips were very helpful and made our work much easier. The HöhenFreak hoodies we were given also kept us very nice and warm in extreme conditions."