Effects of changes in groundwater level on palsas in central Iceland
Bog ; Cold area ; Humid environment ; Hydrology ; Iceland ; Palsa ; Periglacial features ; Permafrost ; Vegetation
The effects of the changed hydrological conditions on 5 palsas were monitored over a period of 5 years. All the palsas increased in height. A core through one palsa showed that while it was formed by segregation ice, the observed height increases
Palsas in Härjedalen, Sweden : 1910 and 1988 compared
Biogeography ; Climatic index ; Microrelief ; Palsa ; Peat bog ; Periglacial features ; Precipitation ; Sweden ; Temperature ; Wind
In 1998 an area near Helagsfjället was investigated in an attempt to relocate palsas discovered by the botanist Harry Smith in 1910. Several small palsa-like features with ice cores were detected. This location is the most southerly area known
with occurrence of palsa-like forms in Sweden at the present time. In spite of a warmer climate towards the latter part of this century, palsa-like features have survived in this area. The palsa formation is probably dependent on strong winds thinning out
How to make a palsa: a field experiment on permafrost formation
Cold area ; Experimentation ; Finland ; Lapland ; Palsa ; Periglacial features ; Permafrost ; Snow
This paper presents a natural scale field experiment on palsa formation. In this study only one parameter, which was thought to be critical one in this environment for the formation of permafrost is varied. The factor was snow depth, which
Depth of snow and forst on a palsa mire, Finnish Lapland
Analysis of snow and frost measurements made on a palsa mire in Utsjoki, northernmost Finland from September 1984 to October 1985. Rather good multiple and logarithmic regressions were found between snow and frost depths of March and April
. This type of condition makes possible a new palsa formation.
Palsar i Nord-Norge. En studie av palsars morfologi, utbredning och klimatiske forutsättningar i Finnmark och Troms fylke A study of the palses'morphology, extension and climatic preconditions in the counties of Troms and Finnmark
Modelling the distribution of palsas in Finnish Lapland with logistic regression and GIS
Aerial photography ; Finland ; Geographical information system ; Modelling ; Palsa ; Periglacial features ; Permafrost ; Photointerpretation ; Regression analysis ; Spatial distribution
The location of palsas (peat mounds with a perennially frozen core) was mapped in an area of 3370 km2 in Finnish Lapland by interpreting aerial digital photographs. Using environmental variables derived from digital land cover data and an elevation
model, the distribution of palsas was modelled using geographic information system (GIS) techniques and multiple logistic regression. The relative roles of 8 environmental variables potentially affecting the distribution of the palsas were studied
in a spatial grid system with 3370 grid squares of 1.0 km2, of which 172 were found to contain palsas.
Spatial modelling of palsa mires in relation to climate in Northern Europe
Climate ; Climatic data ; Cold area ; Europe ; Geographical information system ; Model ; Northern Europe ; Palsa ; Periglacial features ; Permafrost ; Spatial distribution
Palsa mires are mire complexes that occur in the Northern Hemisphere, representing one of the most marginal permafrost features at the outer limit of the permafrost zone. A climate-based generalized linear model (GLM) of the spatial pattern of palsa
mires is presented in relation to a large number of climatological variables using GIS tools. The results indicate a positive association of the distribution of palsa mires with increasing frost number and continentality, whereas precipitation
and temperature showed a negative correlation with the distribution of palsa mires. Additionally, interaction of thawing degree days and summer time precipitation showed a negative association.
There is no general agreement about the meaning of the word palsa. Usage and recent suggested definitions indicate that the word is chiefly used for cryogenic mounds covered by peat that were formed by an accumulation of segregation ice
in the discontinuous permafrost zone. Lithalsas are similar mounds, but without any peat cover. Use of development and decay palsas as indicators of climatic change is difficult. The climatic conditions in which lithalsas form are much more restricted than those
for palsas. Some of the pingo remnants described in western Europe are, more accurately, lithalsa traces.
Non-invasive geophysical investigation and thermodynamic analysis of a palsa in Lapland, Northwest Finland
Climatic warming ; Cold area ; Collapse structures ; Finland ; Geophysics ; Ground penetrating radar ; Humid environment ; Model ; Northwest Finland ; Palsa ; Permafrost ; Soil temperature ; Thermodynamics
Desmoronamiento ; Finlandia ; Geofísica ; Medio húmedo ; Modelo ; Palsa ; Pergelisol ; Recalentamiento climático ; Temperatura del suelo ; Zona fría
Non-invasive geophysical prospecting and a thermodynamic model were used to examine the structure, depth and lateral extent of the frozen core of a palsa near Lake Peerajärvi. A simple thermodynamic model verified that the current climatic
conditions in the study area allow sustainable palsa development. A ground penetrating radar (GPR) survey of the palsa under both winter and summer conditions revealed its internal structure and the size of its frozen core. GPR imaging in summer detected
core of the palsa. The presence of the frozen core could also be traced as minima in surface temperature and ground conductivity measurements. These field methods and thermodynamic models can be utilised in studies of climate impact on Arctic wetlands.
The ramparted depressions that exist on the Hautes Fagnes Plateau in Belgium, first interpreted in 1956 as the remnants of pingos are best explained as remnants of lithalsas (i.e., mineral palsas), formed from ice segregation within frozen ground
Canada ; Climatic change ; Environmental degradation ; Palsa ; Peat bog ; Periglacial features ; Permafrost ; Quebec
Cambio climático ; Degradación del medio ambiente ; Palsa ; Pergelisol ; Periglaciar ; Turbera
Small palsas with very thin frozen layers are present within the peat deposits east of James Bay. Most of these permafrost landforms are in an advanced stage of decay within raised bogs between 51°45N and 55°N. Air photographs, air-borne surveys
Aeolian deflation ; Cold area ; Finland ; Geomorphological mapping ; Lapland ; Model ; Palsa ; Periglacial features ; Solifluction ; Statistics ; Subarctic zone
The AA. downscaled 4 different periglacial features (wind deflation, palsa mire, earth hummock and sorted solifluction sheet) from a 100 ha grid to a 1 ha grid resolution utilizing 2 different techniques : point sampling (PSA) and direct (DA
of the palsa mire and solifluction sheet models was excellent, whereas the AUC values of deflation and earth hummock models were lower.