Climatic and geomorphic factors affecting contemporary (1950-2004) activity of retrogressive thaw slumps on the Aklavik Plateau, Richardson Mountains, NWT, Canada
Arctic Region ; Canada ; Climate ; Climatic change ; Ground ice ; Mass movement ; Mountain ; Northwest Territories ; Periglacial features ; Permafrost ; Thawing ; Thermokarst
The climatic and geomorphic factors affecting retrogressive thaw slump initiation and activity on the Aklavik Plateau (Richardson Mountains, NWT) were examined using historical air photographs over a 54-year period (1950-2004). All thaw slumps
on the Aklavik Plateau are located within the glacial limit of the Laurentide Ice Sheet and the majority developed on the western side of the valley on gently sloping terrain. Aerial photographic analysis showed an increase in thaw slump initiation over the 1954
-71 period and over the 1985-2004 period. However, the total number of active mature thaw slumps on the Aklavik Plateau decreased from a maximum of 46 in 1950 to a minimum of 24 observed in 2004. Both these trends may relate to the influence of climate
on the erosional processes that are thought to initiate thaw slumps and keep them active in regions of highlands.
Freeze-thaw cycles on rock surfaces below the timberline in a montane zone : field measurements in Kobugahara, Northern Ashio Mountains, Central Japan
Freeze-thaw cycle ; Honshu ; Japan ; Mountain ; Surface temperature ; Tree line ; Weathering
continually every 30 min from December 1, 2002 through December 13, 2004 by thermistor probes connected to miniature data loggers. The diurnal and the annual freeze–thaw cycles and effective freeze–thaw cycles were recorded at each site. The freezing index
Creep ; Ground ice ; Hokkaido ; Japan ; Mountain ; Periglacial features ; Slope dynamics ; Solifluction ; Thawing
of soil moisture and ice segregation. Seasonal freeze-thaw cycles produced both frost creep and gelifluction. In layers shallower than 60 cm, ice segregation during the freezing season induced seasonal frost heave, and ice melt at the same depths during
the thaw season promoted gelifluction as well as seasonal frost creep. At greater depths, gelifluction did not occur even when the thaw plane reached the ice-rich layers. The results at the study site demonstrate that segregated ice plays an important role
Climatic warming ; Cold area ; Global change ; Periglacial features ; Permafrost ; Polar region ; Russia ; Soil temperature ; Thawing ; Thermal regime
ground temperatures measured in existing and new boreholes show a substantial warming during the last 20 to 30 years. Thawing of permafrost is most noticeable within the discontinuous permafrost domain. However, permafrost in Russia is also starting
to thaw at some limited locations in the continuous permafrost zone. As a result, a northward displacement of the boundary between continuous and discontinuous permafrost zones was observed.
The study was conducted in the watershed of the Zuomaokong River in an alpine meadow over a three-year period. A high vegetation cover (93%) delayed thawing and freezing at a given depth relative to sites with lower covers (65%, 30% and 5%). Low
Active layer ; Adaptation ; Climatic warming ; Cold area ; Global change ; Northern hemisphere ; Periglacial features ; Permafrost ; Polar region ; Soil temperature ; Thawing ; World
in climate and ecosystem models and an important objective should be to define typical pedons appropriate for model setups. The thawing permafrost carbon feedback needs to be included in model projections of future climate change.
Active layer ; Climatic warming ; Cold area ; Europe ; Global change ; Periglacial features ; Permafrost ; Polar region ; Scandinavia ; Soil temperature ; Spatial variation ; Thawing ; Thermal regime