Our visit to Kohnen Station was a short one, as we arrived at 4 pm yesterday and were on the move again by 8 o'clock this morning. Kohnen Station itself may be but a brief human presence on the plateau – though with some significant scientific achievements on its record.
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