In Alaska, the project named «2004 Forest Fire Impacts to Hydrological Cycles, Permafrost and Eco Systems in Central Alaska» started in 2005 was carried out in the summer of 2006 to monitor permafrost conditions after a severe wildfire (M. Fukuda, K. Harada, Y. Sawada and K. Narita). Observations were carried out at Poker Flat near Fairbanks in July and August, and at Kougarok near Nome in August. In 2006, water and thermal conditions in the active layer were investigated by electrical soundings and pit surveys. These data will be compared with those in 2005 and 2007, and will be used for the prediction of the impacts of wildfire on permafrost.
In eastern Tibet, the final field campaign was undertaken in the mid-summer of 2006 for the five-year Japan- China joint project on «Permafrost Hydrology in the Source Area of the Yellow River» (N. Matsuoka, A. Ikeda, T. Sueyoshi, T. Ishii, C. Gao, Z. Han, and J. Ding). The fieldwork involved data collection from the frozen ground observatory at Madoi (4273 m asl) established in 2004 and seismic sounding at a number of localities on the Tibetan Plateau (4000-4700 m asl). The observatory data suggest that the Plateau ground quickly responds to the change in air temperature because of the minimum snow cover (< 20 cm thick) and generally dry active layer. This condition accounts for the rapid degradation of permafrost and resulting lowering of the groundwater level during the last 20 years, which is indicated by drilling and geophysical sounding.
In Adventdalen, Svalbard, permafrost and periglacial processes were investigated as a part of the Japan-Norway joint project on «Constructing model experimental sites for periglacial processes» (N. Matsuoka, A. Ikeda, T. Watanabe, M. Kobayashi, H.H. Christiansen and O. Humlum). In July 2006, continuous data on ice-wedge cracking, rock weathering and rock glacier creep were acquired from the experimental sites. Subsurface structure below periglacial topography (polygons and hummocks) was also explored with two-dimensional geoelectrical profiling and ground penetrating radar.