Using ice-scars as indicators of exposure to physical lakeshore disturbances, Corvette Lake, northern Québec, Canada
Canada ; Cold area ; Dendrochronology ; Dendrology ; Ice ; Impact ; Lake ; Lake hydrology ; Lake level ; Lake shore ; Landscape structure ; Quebec ; Space time ; Vegetation ; Wave
The hypothesis tested here is that ice-scars recorded by lakeshore tree stands can be used as an integrative proxy indicator of the overall hydrodynamic disturbance regimes affecting northern lakeshores. This study was conducted on a shoreline
segment located at the extreme east of Corvette Lake, situated in the high-boreal climatic zone of northern Quebec. A significant relationship was found between ice-scar chronology and wave exposure index, which indicates that the mechanical action
and physical force of ice activity mainly depend on the same environmental factors determining exposure to wave action (fetch, wind direction and velocity, and shore slope). The spatial and temporal variability of ice-scar chronology features also corresponded
to the distribution of geomorphological features associated with ice activity along the shoreline. Together, ice-scars and wave exposure index provide essential information to interpret the evolution of lakeshore vegetation mosaics in time and space.
A 2D model for characterising first-order variability in sublimation of buried glacier ice, Antarctica : assessing the influence of polygon troughs, desert pavements and shallow subsurface salts
Antarctica ; Cold area ; Glacier ; Ice ; Ice wedges ; Microclimate ; Model ; Numerical model ; Patterned ground ; Periglacial features ; Permafrost ; Polar region ; Sublimation ; Temperature
To assess the role of thermal contraction-crack polygons (sublimation polygons) in modulating sublimation of buried glacier ice in Antarctica, the AA. applied a 2D numerical model using COMSOL Multiphysics that calculates the rate and spatial
variability of vapour diffusion through porous media. Specifically, they examined vapour transport through Granite drift, a dry supraglacial till marked with thermal contraction-crack polygons that rests on glacier ice reportedly >8-million years in age
. The model results show that sublimation varies with drift texture and surface topography. The importance of including field-based data for drift texture, topography and microclimate variation in modelling ice sublimation is highlighted. The results also
suggest that stable conditions (no ice loss) at polygon centres are possible with either a 1.9°C decrease in mean annual atmospheric temperature or a 12 per cent increase in mean annual relative humidity.
Development of covered karstic dolines in ground ice environment (Eastern Alps, Austria). Interests of experimental and mathematical modelling
Alps (The) ; Austria ; Doline ; Ground ice ; Karst ; Meltwater ; Mountain ; Periglacial features ; Permafrost ; Piping
The AA. studied the evolution of dolines in ground ice environment, in a paleouvala of the Hochschwab Mts. (Northern Calcareous Alps, Austria) as well as in laboratory conditions. They measured the ground ice thickness by geophysical methods
. They estimated the melting (thinning) speed and the pertinent parameters for ground ice samples at different temperatures in laboratory conditions. After simulating the process, the AA. were able to determine the physical conditions generating the ground ice
melting phenomena, and based on this they calculated its melting speed. Due to the air circulation in the karst, the lower level of the ground ice starts to melt and the covering sediment particles fall down. Thus the thinned covering sediments will fall
In this study, flume experiments of flows under a simulated ice cover are presented. Open water conditions and simulated rough ice-covered flows are discussed. Mean flow and turbulent flow statistics were obtained from an Acoustic Doppler
Velocimeter (ADV) above a gravel-bed surface. A central region of faster flow develops in the middle portion of the flow with the addition of a rough cover. The turbulent flow characteristics are unambiguously different when simulated ice covered conditions
are used. Two distinct boundary layers (near the bed and in the vicinity of the ice cover, near the water surface) are clearly identified, each being characterized by high turbulent intensity levels. Detailed profile measurements of Reynolds stresses
and turbulent kinetic energy indicate that the turbulence structure is strongly influenced by the presence of an ice cover and its roughness characteristics.
Ice-avalanche impact landforms : the event in 2003 at the glacier Nördliches Bockkarkees, Hohe tauern Range, Austria
The hanging glacier Nördliches Bockkarkees represents the only Austrian glacier that formed large and hazardous ice avalanches over the last decades. This paper focuses on geomorphic and glaciological field measurements and observations at and below
the ice avalanche deposit and its vicinity after the event. Studies were made (a) at the deposited material itself, (b) at the reshaped land surface below the deposit after ice melt, (c) at the front and margin of the deposit, and (d) outside the deposit
. This study reveals different types of ice-avalanche impact landforms comparable to landforms caused by snow avalanches. It is shown that ice avalanches charged with debris at the Nördliches Bockkarkees are important in forming and reshaping erosional
On the burrowing impact of ice rats Otomys sloggetti robertsi at a wetland fringe in the Afro-alpine zone, Lesotho
Recent work has indicated that the southern African ice rat is responsible for negative habitat change due to its foraging and burrowing activities in the Lesotho Highlands. Previous work has focussed on short-term studies. This study evaluates
a ten-year monitoring period across a portion of wetlandfringe/wetland in eastern Lesotho. It is suggested that the environmental impact of ice rats may be less dramatic on the longer term scale due to shifts in of colonies and regeneration of abandoned
Cave development under the influence of Pleistocene glaciation in the Dinarides - an example from Štirovača Ice Cave (Velebit Mt., Croatia)
The aim of this study is to examine the effect of Pleistocene glaciations on the speleogenesis of Štirovača Ice Cave, based on analyses of surface and cave morphology and of cave sediments, since it is well known that caves, and particularly clastic
sediments in caves, contain abundant information on speleogenesis and on the conditions of karstification. The AA. assume that Štirovača Ice Cave represents an important archive in regard to tha glacial history of the Velebit Mt.
Thermal regime of a cold air trap in central Pennsylvania, USA : the Trough Creek ice mine
Air froid ; Anomalie thermique ; Bioclimatologie ; Etats-Unis ; Grotte ; Pennsylvania ; Température ; Température de l'air ; Trough Creek ice mine
Air temperatures internal and external to a talus cave (ice mine) in central Pennsylvania were measured hourly for 3 years. Despite its location near the base of a talus slope, the cave demonstrated the thermal characteristics of an apparently
static cave, with limited connections to the external environment other than through the cave entrance. Congelation ice that lasted until late spring formed as drip or flowstone and ponded ice from the limited influx of infiltrating water during late
Two-dimensional numerical models (FLAC 6.0) were used to explore how edifice shape, rock stiffness and various levels of ice inundation affect edifice shaking intensity. The modelling confirmed that earthquake shaking is enhanced with steeper
topography and at ridge crests but it showed for the first time that total inundation by ice may reduce shaking intensity at hill crests. The effect is diminished to about 80-95% if glacier ice level reduces to half of the mountain slope height. In general
, ice cover reduced shaking most of the steepest-sided edifices, for wave frequencies higher than 3 Hz, and when ice was thickest and the rock had shear stiffness well in excess of the stiffness of ice. The modelling supports the idea that topographic
Late Pleistocene ice fluctuations and glacial geomorphology of the Archipiélago de Chiloé, southern Chile
Paleoglacial features that occur in central Chiloé are characteristic of an ice-sheet style of glaciation, which differentiates it from a typical Alpine glacial style defined previously for the Chilean Lake District (CLD). Therefore
, the Archipiélago de Chiloé represents a geographical break point where the Patagonian ice sheet (PIS) became the large ice mass that occupied the Patagonian Andes during the last glacial period (Llanquihue Glaciation). A double ice-contact slope on the east face
Mudboil and ice-wedge dynamics investigated by electrical resistivity tomography, ground temperatures and surface movements in Svalbard
Active layer ; Arctic Region ; Electrical resistivity tomography ; Freeze-thaw cycle ; Geophysics ; Ice wedge ; Patterned ground ; Periglacial features ; Permafrost ; Soil properties ; Soil temperature ; Svalbard
The AA. applied electrical resistivity tomography (ERT) to understand near-surface conditions of 2 types of patterned ground, ice-wedge polygons and mudboils in Svalbard. Automated monitoring shows surface movement characterized by annual cycles
of frost heave and thaw settlement, the amounts and rates of which are influenced by the intensity of ice segregation. A time series of ERT shows (1) a distinct resistivity boundary delimiting the active-layer depth, (2) seasonal variation in resistivity
controlled by thermo-hydrological dynamics and (3) spatial variation in resistivity reflecting desiccation in summer and intensive ice segregation in winter. These results demonstrate ERT as a useful complementary technique for monitoring active-layer depths
Altai Mountains ; Asian part of Russia ; Geocryology ; Ice ; Lithalsa ; Periglacial features ; Permafrost ; Sedimentology ; Siberia ; Soil properties ; Stratigraphy
almost its entire vertical cross-section, revealing its internal structure. The frozen core consisted mainly of soil segments suspended in reticulate ice lenses with a mean thickness of 11-48 mm and a maximum thickness of about 160 mm. The shapes
of the soil segments matched their neighbours. Other features included soil segments suspended in the ice veins shaped like En echelon gash veins, and the presence of a radial structure of ice-rich and sediment-rich frozen bands. These features all suggest
the greater importance of a differential stress field during heaving of the mound and after ice segregation, compared to the thermal gradient and water supply.
Ablation of ice-cored moraine in a humid, maritime climate : Fox Glacier, New Zealand
To evaluate the effects of varying debris-cover and climate on ice-melt in a maritime mid-latitude setting, an 11-day ablation stake study was undertaken on ice-cored moraine at Fox Glacier. Ablation rates varied with enhancement of melt-rate under
produced from topographic surveys of the ice-cored moraine over the following months indicated that ablation rates progressively decreased over time, probably due to melt-out of englacial debris increasing debris-cover thickness. The morphology
Annual accumulation over the Greenland ice sheet interpolated from historical and newly compiled observation data
Climatic data ; Coastal environment ; Forecast ; Geographical information system ; Geostatistics ; Glacial deposit ; Glacial features ; Glacier mass balance ; Greenland ; Ice sheet ; Krigeage ; Spatial analysis
In this study, the AA. kriged and analyzed the spatial pattern of accumulation based on an observation data series including 315 points used in a recent research, plus 101 ice cores and snow pits and newly compiled 23 coastal weather station data
patterns of accumulation over the Greenland ice sheet.
Climatic change ; Glacial landform ; Glaciation ; Glacier mass balance ; Ice ; Mars planet ; Remote sensing
Mars’ mid-latitude ice was deposited. They then define and describe the various ice-related landforms that have been identified within Mars’ mid-latitudes, and they review the processes that have been proposed to explain the origin and physical
This progress report is the first of 3 overviews of important fields of study within contemporary glaciology, highlighting key developments in each field since 2005. The topics covered in this paper are : (1) the mass balance of glaciers and ice
sheets and their contributions to global sea level change; and (2) atmospheric melt-induced influences on the dynamics of the Greenland Ice Sheet. The paper aims to provide an overview of key developments over the last six years from each topic
Controlled, ice-cored moraines: sediments and geomorphology. An example from Ragnarbreen, Svalbard
in this end moraine complex. However, the intensity of gravity flows is much lower now than it was in the early stages of end moraine complex development. The stability of the ice-cored moraines is due mainly to the thickness of the covering debris, which
protects the ice from melting. The occurrence of fine sediments on the contemporary hills suggests that the end moraine complex has undergone at least one cycle of topographic inversion. The analysis of landforms and deposits occurring in the end moraine