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  • Utility of classification and regression tree analyses and vegetation in mountain permafrost models, Yukon, Canada
  • Canada ; Classification ; Cold area ; LANDSAT ; Model ; Northwest Territories ; Periglacial features ; Permafrost ; Regression analysis ; Remote sensing ; Spatial distribution ; Tree ; Vegetation ; Vegetation index ; Yukon
  • Classification and regression tree (CART) analyses were undertaken to test the usefulness of including vegetation variables in mountain permafrost distribution models for 5 widely spaced study areas in the Yukon. Digital elevation model (DEM
  • )-derived variables, field-derived vegetation variables and satellite imagery-derived vegetation variables were employed individually to classify sites into permafrost probable, permafrost improbable and permafrost ‘uncertain’ categories. The vegetation
  • variables were subsequently combined with the DEM-derived set to see if they could improve the latter's accuracy. CART analyses appear useful for predicting permafrost distribution because they can incorporate non-linear relationships between independent
  • variables and the presence of permafrost.
  • 2011
  • Vegetation canopy and radiation controls on permafrost plateau evolution within the discontinuous permafrost zone, Northwest Territories, Canada
  • Aerial photography ; Canada ; Climatic change ; LiDAR ; Northwest Territories ; Periglacial features ; Permafrost ; Plant canopy ; Plateau ; Radiation ; Remote sensing ; Satellite imagery ; Spatial variation ; Vegetation
  • This study examines the links between the spatial distribution of three-dimensional vegetation structural characteristics and historical permafrost plateau area changes using airborne light detection and ranging and aerial photography. The results
  • show that vegetation is prone to reduced canopy fractional cover and reduced canopy heights at the edges of plateaus. Increased incident shortwave radiation may result in augmented thawing of permafrost and increased meltwater runoff, which further
  • inhibits vegetation and permafrost persistence. Edge influences on ground thaw cause vegetation to die over several years (confirmed using historical aerial photography), thereby exacerbating thaw and plateau area reduction. Permafrost degradation is also
  • 2011
  • Degrading mountain permafrost in southern Norway : spatial and temporal variability of mean ground temperatures, 1999–2009
  • Climatic warming ; Degradation ; Geophysics ; Interannual variability ; Mountain ; Norway ; Periglacial features ; Permafrost ; Seasonal variability ; Soil temperature ; Southern Norway
  • permafrost, marginal permafrost and deep seasonal frost. Ongoing permafrost degradation is suggested both by direct temperature monitoring and indirect geophysical surveys. Increased snow depths and an increase in winter air temperatures appear to be the most
  • important factors controlling warming observed over the ten-year period. Geophysical surveys performed in 1999 to delineate the altitudinal limit of mountain permafrost were repeated in 2009 and 2010 and indicated the degradation of some permafrost over
  • 2011
  • Classification ; Inventory ; Mountain ; Norway ; Periglacial features ; Permafrost ; Rock glacier ; Spatial distribution
  • In total 307 permafrost landforms have been mapped, consisting of rock glaciers and ice-cored moraines. The landforms were classified as active/inactive (intact) or relict landforms, and by origin. In northern Norway, permafrost landforms exist down
  • to sea level and the majority of the landforms are relict talus-derived rock glaciers. In southern Norway, permafrost landforms are restricted to high elevations and the majority of the landforms are connected to glacial activity and classified as active
  • . In the present paper, this contrasting pattern is interpreted to reflect that different processes leading to a permafrost landform also represent different ages and climatic regimes during their formation.
  • 2011
  • Sensitivity and path dependence of mountain permafrost systems
  • Alps (The) ; Bavaria ; Climatic change ; Concept ; Germany ; Mountain ; Palaeoclimate ; Periglacial features ; Permafrost ; Scenario ; Sensitivity analysis
  • This article is an attempt to transfer a classical geomorphological concept – the sensitivity concept by Brunsden and Thornes – onto mountain permafrost systems. Focus is put on the impulses applied on the system and its subsequent response
  • . The system state, the ratio between sensitivity and resistivity, as well as all system components and the external impulses are understood to be variable in space and time. In order to address sensitivity and path dependence in mountain permafrost systems
  • 2011
  • Characteristics of discontinuous permafrost based on ground temperature measurements and electrical resistivity tomography, Southern Yukon, Canada
  • Canada ; Climatic variability ; Cold area ; Electrical resistivity tomography ; Geophysics ; Ground ice ; Northwest Territories ; Palsa ; Periglacial features ; Permafrost ; Thermal regime ; Yukon
  • Warm permafrost conditions (mean temperatures of −3°C to −0.1°C) were investigated in detail at 13 valley and mountain sites in the sporadic (10–50%) and extensive (50–90%) discontinuous permafrost zones in the southern half of the Yukon (60°N to 64
  • in the spring imaged both deep seasonal frost and perennially frozen ground. The observations revealed the complexity of site conditions where permafrost is discontinuous and the utility of ERT, in combination with other methods, to investigate permafrost
  • 2011
  • On the connection between debris flow activity and permafrost degradation : a case study from the Schnalstal, South Tyrolean Alps, Italy
  • Alps (The) ; Climatic warming ; Debris flow ; Degradation ; Italy ; Model ; Mountain ; Periglacial features ; Permafrost ; Spatial distribution
  • The possible influence of permafrost degradation on the formation of debris flows in an area of the South Tyrolean Alps was examined by comparing debris flow activity since 1983 with the modelled contemporary permafrost distribution. The study
  • focused on the spatial congruence of new initiation zones and potentially marginal permafrost, which should be especially sensitive to climatic change and is presumed to be currently degrading. The results show that distinct changes in the spatial position
  • of debris flow initiation areas mainly occurred at elevations above this marginal zone. Consequently, the changes detected in debris flow activity do not appear to have been influenced by atmospheric warming-induced degradation of permafrost. However, a link
  • 2011
  • Equivalent elevation: a new method to incorporate variable surface lapse rates into mountain permafrost modelling
  • Air temperature ; Canada ; Cold area ; Lapse rate ; Model ; Mountain ; Northwest Territories ; Periglacial features ; Permafrost ; Tree line ; Yukon
  • Permafrost is present at multiple elevations with no defined lower limit in the southern Yukon Territory, Canada. Empirical statistical modelling of permafrost probability in the region required the development of equivalent elevation, a new
  • temperatures at nearby climate stations, which permits prediction of equivalent elevation for the entire region. Permafrost probability modelling using equivalent elevation produced statistically significant results in several study areas.
  • 2011
  • Permafrost thermal regime from two 30-m deep boreholes in Southern Victoria Land, Antarctica
  • Active layer ; Air temperature ; Antarctica ; Climatic change ; Cold area ; Permafrost ; Polar region ; Soil temperature ; Temperature ; Thermal regime
  • Two 30-m deep permafrost temperature-monitoring boreholes were installed in bedrock, one at Marble Point and one in the Wright Valley, in the Ross Sea region of Antarctica. A soil climate-monitoring station in till is located near each borehole
  • . The main aims of this paper are: (1) to describe the permafrost temperatures and active-layer thermal regime at these two sites in southern Victoria Land; and (2) to derive a climate change record over the last 10 years from the permafrost borehole
  • 2011
  • Effects of ice content on the thermal erosion of permafrost: implications for coastal and fluvial erosion
  • Bank erosion ; Coastal erosion ; Cold area ; Erosion rate ; Experimentation ; Fluvial erosion ; Geophysics ; Ice content ; Impact ; Meltwater ; Model ; Periglacial features ; Permafrost ; Runoff ; Thermokarst ; Water erosion
  • The effects of ice content and water flow on thawing and erosion of non-cohesive permafrost banks were investigated through laboratory experiments. A critical ice content was identified as associated with turbulent flows, above which thermal erosion
  • 2011
  • [b3] Melnikov Permafrost Inst., Russian Academy of Sciences, Sakha (Yakutia) Republic, Russie, Federation de
  • Biogeochemical and geocryological characteristics of wedge and thermokarst-cave ice in the CRREL permafrost tunnel, Alaska
  • Alaska ; Biogeochemistry ; Carbon ; Cold area ; Ice ; Ice wedge ; Meltwater ; Model ; Nutrient ; Periglacial features ; Permafrost ; Solution load ; Thermokarst
  • Partially eroded ice wedges and lenticularly shaped bodies of massive thermokarst-cave ice in ice-rich syngenetic permafrost (yedoma) are exposed in the CRREL tunnel near Fairbanks, Alaska. Here, the AA. report the biogeochemical characteristics
  • characteristics. Current estimates of soluble solutes stored in permafrost may underestimate the total carbon and nutrient load where wedge material has been extensively replaced by surface water rich in organic carbon, nutrients or inorganic solutes.
  • 2011
  • Physical modelling of rainfall- and snowmelt-induced erosion of stony slope underlain by permafrost
  • Climatic warming ; Erosion ; Experimentation ; France ; Freeze-thaw cycle ; Model ; Periglacial features ; Permafrost ; Precipitation ; Slope dynamics
  • Physical modelling experiments have been carried out in a cold room to test on a small scale, the effects of water supply during the thaw of an experimental slope with permafrost. Permafrost was maintained at depth and a thin active layer was frozen
  • 2011
  • Alaska ; Collapse structures ; Floating vegetation ; Geophysics ; Ground-penetrating radar ; Lake ; Periglacial features ; Permafrost ; Remote sensing ; Thawing ; Thermokarst
  • Investigations on the northern Seward Peninsula in Alaska identified zones of recent permafrost collapse that led to the formation of floating vegetation mats along thermokarst lake margins. This paper reports on the recent expansion
  • of these collapse features on Lake Rhonda and Lake Owl and their geometry is determined using geophysical and remote sensing measurements. In addition, the AA. determined the extent of thawed permafrost obscured by floating vegetation mats at the study site
  • 2011
  • [b2] Permafrost Lab., Geophysical Inst., Univ. of Alaska, Fairbanks, Etats-Unis
  • Inheritated geomorphological features ; Mountain ; Palaeogeography ; Patterned ground ; Periglacial features ; Permafrost ; Plain ; Poland ; Present time ; Spatial distribution ; Upper Pleistocene
  • -scale non-sorted polygons, and can only be observed on aerial pictures taken under conditions of suitable weather, lithology and land use. The polygons attest to permafrost conditions during the last Pleistocene glaciation. In turn, in the alpine
  • 2011
  • Altitude ; Andes ; Model ; Periglacial features ; Permafrost ; Peru ; Rock glacier ; Soil temperature ; Volcano
  • This article analyses temperature variations around 0°C in shallow ground and the elevational distribution of annual average air temperatures, to determine elevational boundaries for periglacial and permafrost environments in the Chachani volcanic
  • 2011
  • Arctic Region ; Climatic change ; Climatic warming ; Eurasia ; Global change ; Habitat ; Natural resources ; Permafrost ; Sea transport ; Society-environment relationship
  • manifestations of a warming Arctic climate, including reduced Arctic ice cap thickness and extent, reduction of the continuous permafrost zone, and changes in the conditions of terrestrial and marine habitats in the Far North. It explores how these changes have
  • 2011
  • Eurasia ; Geomorphology ; Glacial features ; Glacier fluctuation ; Inheritated geomorphological features ; Mountain ; Permafrost ; Quaternary ; Slope dynamics ; World
  • during cold stages a pronounced role was played by expansion of permafrost in western direction. The limits of vertical zones of geomorphic processes are frequently adapted to inherited features of relief and especially to relief energy. High rate
  • 2011
  • Alps (The) ; Electrical resistivity tomography ; Freezing ; Geophysics ; Infiltration ; Mountain ; Periglacial features ; Permafrost ; Snow cover ; Switzerland ; Thawing
  • , as opposed to single measurements at irregular time intervals, are illustrated using the permafrost monitoring station at the Schilthorn, Swiss Alps. Results from a one-year dataset show small temporal changes during periods with snow cover, and the largest
  • at greater depths, the new A-ERT system can be widely applied in permafrost regions.
  • 2011
  • Alps (The) ; Climatic change ; Digital elevation model ; High mountain ; Italy ; LiDAR ; Periglacial features ; Permafrost ; Photogrammetry ; Remote sensing ; Rockfall ; Slope dynamics ; Time series ; Twentieth Century
  • This paper describes a remote sensing-based approach for detailed topographic investigations in steep periglacial high-mountain faces. The study was conducted in the European Alps, at the permafrost-affected and partially glacierised east face
  • and detachment zones showed that the sequence of the main slope failures is spatially connected and that there is coupling between permafrost bedrock instability and the condition of adjacent hanging glaciers.
  • 2011
  • Climatic change ; Crack ; Experimentation ; Heat transfer ; Meltwater ; Model ; Mountain ; Numerical model ; Periglacial features ; Permafrost ; Rock ; Rockfall
  • that this energy is not directly detectable in ground temperature records. The results suggest that thawing-related rockfall is possible even in cold permafrost if meltwater production and flow characteristics change significantly. Advective warming could rapidly
  • 2011