Aapasuon routaa säätelevät tekijät - esimerkkitapaus Kuusamosta (Factors controlling groundfrost on an aapa mire in Kuusamo, Finland)
The chief factor controlling the frost horizon in the ground proved to be snow depth which was regulated by wind action, particularly in late winter. The vegetation had a considerable influence locally. The contribution of the third major factor
, the groundwater was seen principally in the fact that the mire accumulated less groundfrost than other sites on average and that the frost began to melt almost a month earlier than in ordinary mineral soils.
Frost heave on earth hummocks (pounus) in Finnish Lapland
Cold area ; Finland ; Freezing ; Frost action ; Ground survey ; Lapland ; Periglacial features ; Snow
tubes above the ground surface. Frost heave values on the pounus did not differ much from those from the surrounding mire. During the early summer, slow thawing of frost keeps the surface of pounus higher than the surrounding mire surface
Frost heave, frost and snow depths on 2 earth hummocks (pounus) were monitored from 1992 to 2002 in Finnish Lapland. Frost heave was measured with motometers, frost depth with Gandahl's frost tube containing methylene blue, and snow depth with frost
Seasonal groundfrost occurrence : developing a statistically-based predictive model
Results suggest that although frost penetration can often be approximated on the basis of freezing degree days, the last frost observed and a qualitative assessment of soil moisture, the overall accuracy of the predictive model is undermined
Frost-cracking conditions, Bylot Island, Eastern Canadian Arctic Archipelago
Air temperature ; Arctic Region ; Canada ; Cold area ; Geophysics ; Ground freezing ; Ice wedges ; Northwest Territories ; Nunavut ; Periglacial features ; Permafrost ; Soil temperature
This paper examines how frost-cracking events are related to variations in air and ground temperatures. The implications of the results for ice-wedge dynamics, frost cracking processes and frozen ground rheology are also discussed. The study site
Frozen ground phenomena in the Northern Foothills, Northern Victoria Land, include large-scale polygons, 15-20 m in diameter, and small frost mounds, 1-5 m high. The polygons are most widespread on terrain formed upon Younger Drift and are usually
surrounded by interpolygon furrows or troughs, 10-30 cm deep and 10-100 cm wide. Field and anecdotal evidence suggest that thermal contraction cracking is active under today's climate. Frost mounds occur in association with a number of perennially frozen
lakes in the region. In most cases they appear related related to frost and icing blister activity caused by the episodic injection of free water from below.
The focus of this paper is on locating and mapping frost-wedge pseudomorphs using electromagnetic induction (EMI). The AA. used EMI at a test site in Belgium to develop a new methodology for locating near-surface frost-wedge pseudomorphs. Besides
Environmental controls on soil frost activity in the Western Cape mountains, South Africa
Cape Province ; Freeze-thaw cycle ; Ground freezing ; Mountain ; Periglacial features ; Precipitation ; Snow cover ; Soil ; Soil moisture ; South Africa ; Vegetation
Field observations on active frost processes in the Western Cape mountains have shown the presence of micropatterned ground and turf- and stone-banked steps and lobes in argillaceous sediments at sites above 1600 m a.s.l. Soil texture plays
an important control on the spatial distribution of soil frost features in this region. 2 microclimatic monitoring stations were established on different substrates at about 1900 m a.s.l. recording air and soil temperature, soil moisture and precipitation over
periods of 5 and 2 years respectively. Results show the region to experience surficial diurnal frost only.
Frost boils and soil ice content : field observations
Alaska ; Climatic variability ; Cold area ; Freeze-thaw cycle ; Ground ice ; Micromorphology ; Patterned ground ; Periglacial features ; Permafrost ; Soil properties ; Soil temperature ; Vegetation index
The AA. measure and explain the seasonal changes in soil ice content in the frost boils of Galbraith Lake, Alaska. They use the changes in soil volume, temperature and thermal properties during freezing and thawing to draw conclusions about changes
in ice volume. Their objectives are to describe the heave dynamics of a frost boil, to quantify the role of seasonal ice growth in these features, and to evaluate the role of ice formation and segregation in differential frost heave at this site.
Development of miniature sorted patterned ground following soil erosion in East Falkland, South Atlantic
and indicate that in cool oceanic climates the distribution of frost-sorted patterns is controlled by the presence of bare ground on suitable regolith rather than by altitude.
The features have developed in the L'Antioja valley, East Falkland, following recent erosion and display many of the characteristics associated with the operation of frost-related processes in regolith materials. The patterns are currently active
Effects of high pine shelterwood on temperature near the ground in Climatological extremes in the mountains, Physical background, geomorphological and ecological consequences.
Frosts during the vegetation period may damage growing plants. The use of shelterwood instead of clearfelling may reduce the risk of frost damage. Measurements of the air temperature near the ground were made in 20 meter tall shelterwoods of Scots
Frost-boil ecosystems : complex interactions between landforms, soils, vegetation and climate
Active layer ; Alaska ; Arctic Region ; Climate ; Cold area ; Cryoturbation ; Ecosystem ; Patterned ground ; Soil properties ; Vegetation
This paper presents observations of frost boils in northern Alaska. It presents a hypothesis of how vegetation affects small-scale patterned-ground features across the complete Arctic climate gradient. Although not directly part of the Circumpolar
-Active-Layer-Monitoring (CALM) project, frost boils influence the thaw layer and are relevant to CALM.
stress and ice segregation during prolonged episodes of permafrost formation in the cold periods of the Pleistocene. Frost wedging and frost heaving (jacking) were the primary mechanisms. Today, climatic conditions on the summits permit only thin
and marginal permafrost bodies. Stonenets and stripes are developed where a residual bedrock-derived debris mantle is present. They reflect frost-induced movements within the active layer. The latest of these movements probably occurred during the cold period
Rates of heave and surface rotation of periglacial frost boils in the White Mountains, California
California ; Freeze-thaw cycle ; High mountain ; Mountain ; Patterned ground ; Periglacial features ; Slope dynamics ; Snow ; Thawing ; United States of America
This paper presents information on active nested patterned ground existing at three distinct scales at elevations ranging from 3900 m to 4150 m in the White Mountains. The processes responsible for the observed movement in the White Mountains
Ground temperature variations in a subarctic mountain valley, Abisko, Northern Sweden
Studies of the ground temperatures and hydrological conditions at four sites on a subalpine heath and in the birch forest in the subarctic valley in Abisko from 1984-87 show that a clear relationship exists between ground temperature and climatic
parameters, especially precipitation through the effects of snow cover. The effects of precipitation poor summers in 1985-87 and the colder than normal and snow poor winters of 1985 and 1987 were instrumental in intensifying the effects of seasonal frost
Forms of unusual patterned ground: examples from the Falkland Islands, South Atlantic
Aeolian features ; Atlantic Ocean ; Earth surface processes ; Island ; Lacustrine sediment ; Patterned ground ; Peat ; Sand ; Sediment transport ; South Atlantic Ocean
This paper descibes the characteristics of, and outlines the most likely origins for, three forms of unusual patterned ground observed in the Falkland Islands, South Atlantic. The features here described are not products of frost-related processes