Snow research in the Antarctic

Blog from the Antarctic

SLF snow researcher Martin Schneebeli has been taking part in a study expedition in the Antarctic since December 3. His regular blog (in German) gives an insight into his work and illuminates his experiences in and impressions of the Antarctic.

Published on 07th Jan. 2013     |    1 comment

Bei den Schneemessungen ist manchmal voller Körpereinsatz gefragt. Dabei kommt es vor, dass ein Messgerät den Geist aufgibt und Flexibilität gefragt ist. Bei einer kleinen, antarktischen „Summer School“ haben sich die Forschenden im Schneegraben getroffen, um den Aufbau der Schneedecke zu diskutieren.

Published on 27th Dec. 2012

In der Antarktis hat Martin Schneebeli eine besondere Himmelserscheinung beobachtet – einen Zirkumzenitalbogen. Im Schneeprofil wurden die Schichten inzwischen mit Spezialfotografie genauer untersucht.

Fig. 1: Antarctic

Winter 2012/13 expedition

In the heart of the Antarctic, the ice can be as much as several thousand metres thick. This ice stores a wealth of information about the climate in the past and thus gives an insight into the continent's history, dating back thousands of years. Given that the air temperature remains permanently below zero degrees, several hundred to a thousand years pass before the snow on the surface metamorphoses into ice. On European glaciers, in contrast, this transformation occurs within just one year. This upper layer of granular snow, known as firn, which can be up to 100 m thick, is the subject of the 2012/13 Antarctic research project.

Martin Schneebeli's role is that of the expedition's snow expert: He is analysing the properties of the uppermost four metres of the firn layer and investigating how its structure has changed with increasing depth. At a depth of four metres, the snow is already 20 to 40 years old because only around 50 to 100 kg of snow falls per square metre in this frozen wilderness (in Europe, the equivalent snow depth would be about half a metre).

Last year, Martin Schneebeli was pursuing a similar goal as a member of the EXPLORE project. Since the time available for fieldwork was ultimately restricted to just three days on that occasion, he seized the opportunity to join the CoFi (Coldest Firn) project. Until the end of January he will be using a variety of instruments developed by the SLF to explore as accurately as possible how snow metamorphoses into firn. It will not be possible to make all the desired measurements in the field, so that he will also be taking snow samples and placing them in a liquid for freezing, or shipping them to the SLF's cold laboratory in insulated crates. These will be examined with the computer tomograph in the summer. By carrying out these investigations, Martin Schneebeli is hoping to answer some of the outstanding questions concerning the climatic history of the Antarctic.

Investigation methods

Field measurements

• Snow profiling (including irradiation) and infrared photography: for examining the structural properties (e.g. grain shape and size) and stratification (layering) of the snowpack. For this purpose, Martin Schneebeli and his team put to the test for the first time a new method which they had developed in advance. First, one side of a snow profile is irradiated with near-infrared light, which is invisible to the human eye, and photographed. By subsequently preparing and irradiating the translucent profile with green light, the grain size and density can be calculated (Fig. 4).
• SnowMicroPen: for measuring the hardness of the snow layers
• Spectrometer: for measuring the reflectivity of snow and ice

Fig. 2: The NIRTRAN infrared device for measuring density and grain size in snow

Laboratory tests

• Computer tomography: for examining the "architecture" of snow and its thermal and mechanical properties