The Bundesanstalt für Geowissenschaften und Rohstoffe, Hannover, and the Centre d’Ètudes Nordiques, Université Laval, Québec (Georg Delisle), joint-project on investigation of the permafrost development in emerged marine sediments near the eastern shore of the Hudson Bay continues into its second year.
Monitoring of subsurface temperatures of a (mineral) palsa east of Umiujaq, Nunavuk shows a mean annual temperature of -0.6°C. A pressure transducer positioned near the bottom of the palsa (at the freezing front) provides a continuous record of the pore pressure indicating a strong hydraulic gradient into the palsa. Numerical modeling to simulate annually the thermal processes within the palsa is in progress. Since the frozen core of the structure is rather close to the melting point of ice, this site offers a unique opportunity to observe the effect of climatic change in the Arctic. Therefore, it is planned to extend the monitoring beyond 2003.
The Potsdam Research Unit of the Alfred Wegener Institute for Polar and Marine Research (Hans-W. Hubberten) co-ordinates the multidisciplinary terrestrial part of the joint German-Russian project ‘System Laptev Sea 2000’. An expedition to the Lena Delta took place in July-August 2001 (Expedition leaders: Eva- Maria Pfeiffer and Mikhail N. Grigoriev), consisting of eight German and eight Russian scientists and technicians from Moscow, St. Petersburg, Yakutsk and Tiksi. One team focused on modern processes in permafrost soils and the underlying frozen sequences and worked from the biological station of the Lena Delta Reserve on Samoylov Island in the central part of the Lena Delta. Since 1998 the energy and water balances of the active layer are registered year round at four sites. During the field season the pedogenic and soil microbial parameters, which control the production, oxidation and emission rates of trace gases, were studied as well as the carbon flux. The emission of CH4 and CO2 from other possible sources, such as lakes and ice complex deposits, have been studied. Surprisingly high methane emissions have been observed from the frozen soil as well as from the ice wedge part of the ice complex. Several cores were drilled down to 8.5 m into the permafrost, which will mainly be used for microbial and molecular biological investigations.
Under the umbrella of the IPA-IASC project ACD (Arctic Coastal Dynamics, Project leader: Volker Rachold, (http://www.awi-potsdam.de/www-pot/geo/acd. html), another team studied the coastal dynamics at the west coast of the Lena Delta from a field camp at Babaryna Island. After investigating the coastal processes at the eastern and western coasts of the Laptev Sea in 1999 and 2000, three weeks were dedicated to studying the complex system of the coast of the sandy Arga Complex, which is separated from the open ocean by shallow lagoons and tens of kilometers long north-south extending sand barriers. An unexpected result was the importance and dominance of wind erosion and accumulation compared to wave action. Apart from geodetic measurements to compare the actual coastline with older aerial photographs in order to determine the rate of coastal retreat, shore face profiles were measured from the barriers to the 10 m isobath and sediment samples were taken. Some results of this project are presented in 14 articles in press in a special volume of the journal Polarforschung, to be printed early next year. A small group from the Alfred Wegener Institute performed geocryological studies in Central Yakutia between the middle Lena and the Aldan rivers in cooperation with the Permafrost Institute, Yakutsk.
The Department of Physical Geogryphy, University of Trier (Christof Kneisel) has continued investigating a mountain permafrost occurrence below the timberline in the Upper Engadine, eastern Swiss Alps. Geophysical measurements were carried out and monitoring of ground temperature is now maintained for the third year to study the physical processes controlling the interaction of permafrost with the environment at this sporadic permafrost site. The measurements of the near surface ground temperature are extended along altitudinal belts from the subalpine zone to the periglacial/subnival zone.
After completion of the PACE project the Giessen PACE group (Lorenz King) continues mountain permafrost research in the Mattertal, Valais, Swiss Alps. Temperature data from the borehole at Stockhornplateau (3410 m) near Zermatt, indicate a permafrost thickness of about 160 m, and an active layer thickness of about 2 m. Coldest ground temperatures of -2.6°C were reached at a depth of 22.5 meters. Further ground temperature measurements have been started at the lower part of the discontinuous permafrost belt in the Gornergrat area above Zermatt. The data will contribute to the project of Thomas Herz concerning the influence of a coarse-grained debris cover on energy transfer processes between atmosphere, lithosphere and ground temperatures in the alpine periglacial belt. In late September 2001, the test area Grächen-Seetalhorn was instrumented with a 30m borehole and a meteorological station.
Mountain permafrost investigations are also carried out in the neighbouring Turtmanntal, Valais, Switzerland by a research group of the Department of Geography at the University of Bonn (Richard Dikau). This valley is characterized by a high density of rock glaciers at all stages of activity. A main objective of the project is to assess the scale dependent significance of rock glaciers to determine the sensitivity of high mountain geosystems to global environmental change. Through the combination of different approaches and methods in various spatial and temporal scales, a holistic approach is planned to be achieved. A sediment budget for the catchment may support the hypothesis that the rock glacier process was the dominant sediment flux in alpine regions during the Holocene. A monitoring programme was started in 1990 with the following objectives: Reconstructing past and present permafrost distribution (Dikau, Nyenhuis, von Witsch) Rock glacier distribution (Nyenhuis), geophysical methods (Nyenhuis, Pfeffer) Rock glacier movement rates applying remote sensing and terrestrial surveying (Roer, von Elverfeldt) Rock glacier movement pattern modelling by process based models (Hoffmann) Bioindication of rock glacier systems (Roer) Periglacial system components and their coupling/ decoupling with the glacial situation (Otto), Quantifying sediment storages (Knopp, Nyenhuis) Surface analysis by remote sensing (Schreiner) and morphometric landscape analyses (Rasemann).
Lorenz King (Lorenz.King@geogr.uni-giessen.de)