Permafrost Mapping Research Articles

A ground temperature map of the North Atlantic permafrost region based on remote sensing and reanalysis data

Abstract. Permafrost is a key element of the terrestrial cryosphere which makes mapping and monitoring of its state variables an imperative task. We present a modeling scheme based on remotely sensed land surface temperatures and reanalysis products from which mean annual ground temperatures (MAGT) can be derived at a spatial resolution of 1 km at continental scales. The approach explicitly accounts for the uncertainty due to unknown input parameters and their spatial variability at subgrid scale by delivering a range of MAGTs for each grid cell. This is achieved by a simple equilibrium model with only few input parameters which for each grid cell allows scanning the range of possible results by running many realizations with different parameters. The approach is applied to the unglacierized land areas in the North Atlantic region, an area of more than 5 million km2 ranging from the Ural Mountains in the east to the Canadian Archipelago in the west. A comparison to in situ temperature measurements in 143 boreholes suggests a model accuracy better than 2.5 °C, with 139 considered boreholes within this margin. The statistical approach with a large number of realizations facilitates estimating the probability of permafrost occurrence within a grid cell so that each grid cell can be classified as continuous, discontinuous and sporadic permafrost. At its southern margin in Scandinavia and Russia, the transition zone between permafrost and permafrost-free areas extends over several hundred km width with gradually decreasing permafrost probabilities. The study exemplifies the unexploited potential of remotely sensed data sets in permafrost mapping if they are employed in multi-sensor multi-source data fusion approaches.

Soil geomorphology and frozen ground conditions at a subalpine talus slope having permafrost in the eastern Swiss Alps

At a subalpine site with permafrost below the timberline in the eastern Swiss Alps the complex interrelationship between different environmental factors was investigated by applying an integrated approach that combines soil mapping, 3D near-surface geophysics and surface and subsurface temperature monitoring. The objectives of this approach were to explore the 3D extension of isolated permafrost bodies and to relate this to surface parameters such as soils and humus forms and other extrinsic factors. Using this procedure, interdependencies between surface (soil properties and humus forms) and subsurface factors (ground thermal regime and frozen ground conditions) could be independently analysed. Although time-consuming, 3D ERI (electrical resistivity imaging) demonstrated its ability for precise permafrost mapping. Despite climate warming, super-cooling in winter along the investigated scree slopes is still efficient enough for establishing permafrost conditions. By comparing the spatial dimensions of the permafrost bodies with surface conditions, we found that thick moss or organic litter layers had an insulating effect and prevented the permafrost from melting. However, the comparison of soil units and soil thickness with the permafrost distribution did not always show an obvious relationship. This indicates that there is a complex evolution and behaviour of soils and permafrost at such sites.

Modelling and mapping climate change impacts on permafrost at high spatial resolution for an Arctic region with complex terrain

Abstract. Most spatial modelling of climate change impacts on permafrost has been conducted at half-degree latitude/longitude or coarser spatial resolution. At such coarse resolution, topographic effects on insolation cannot be considered accurately and the results are not suitable for land-use planning and ecological assessment. Here we mapped climate change impacts on permafrost from 1968 to 2100 at 10 m resolution using a process-based model for Ivvavik National Park, an Arctic region with complex terrain in northern Yukon, Canada. Soil and drainage conditions were defined based on ecosystem types, which were mapped using SPOT imagery. Leaf area indices were mapped using Landsat imagery and the ecosystem map. Climate distribution was estimated based on elevation and station observations, and the effects of topography on insolation were calculated based on slope, aspect and viewshed. To reduce computation time, we clustered climate distribution and topographic effects on insolation into discrete types. The modelled active-layer thickness and permafrost distribution were comparable with field observations and other studies. The map portrayed large variations in active-layer thickness, with ecosystem types being the most important controlling variable, followed by climate, including topographic effects on insolation. The results show deepening in active-layer thickness and progressive degradation of permafrost, although permafrost will persist in most of the park during the 21st century. This study also shows that ground conditions and climate scenarios are the major sources of uncertainty for high-resolution permafrost mapping.

Extending Airborne Electromagnetic Surveys for Regional Active Layer and Permafrost Mapping with Remote Sensing and Ancillary Data, Yukon Flats Ecoregion, Central Alaska

Machine‐learning regression tree models were used to extrapolate airborne electromagnetic resistivity data collected along flight lines in the Yukon Flats Ecoregion, central Alaska, for regional mapping of permafrost. This method of extrapolation (r = 0.86) used subsurface resistivity, Landsat Thematic Mapper (TM) at‐sensor reflectance, thermal, TM‐derived spectral indices, digital elevation models and other relevant spatial data to estimate near‐surface (0–2.6‐m depth) resistivity at 30‐m resolution. A piecewise regression model (r = 0.82) and a presence/absence decision tree classification (accuracy of 87%) were used to estimate active‐layer thickness (ALT) (< 101 cm) and the probability of near‐surface (up to 123‐cm depth) permafrost occurrence from field data, modelled near‐surface (0–2.6 m) resistivity, and other relevant remote sensing and map data. At site scale, the predicted ALTs were similar to those previously observed for different vegetation types. At the landscape scale, the predicted ALTs tended to be thinner on higher‐elevation loess deposits than on low‐lying alluvial and sand sheet deposits of the Yukon Flats. The ALT and permafrost maps provide a baseline for future permafrost monitoring, serve as inputs for modelling hydrological and carbon cycles at local to regional scales, and offer insight into the ALT response to fire and thaw processes. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

Distribution of Permafrost in China: An Overview of Existing Permafrost Maps

ABSTRACTMany permafrost maps in China have been compiled since the early 1960s. The scales of these maps range from the local (1:600 000) to the regional scale (1:10 000 000). The permafrost classification systems differ among these maps. The indices for permafrost classification used in these mapping projects include spatial continuity (areal extent) and thickness of the permafrost, air and ground temperatures and ground ‐ice content. All of those data have been retrieved, digitised and published in the Environmental and Ecological Science Data Center for West China. These maps represent the best understanding at the time regarding the distribution of permafrost in China and its changes over the past century. An updated map of permafrost in China, including frozen ground area, is also provided. The total area of permafrost in China is estimated at ~ 1.59 × 106 km2 (glaciers and lakes excluded), and the area of seasonally frozen ground (excluding instantaneous frozen ground) is ~ 5.36 × 106 km2. The total area of high‐altitude (plateau and mountain) permafrost in China is ~ 1.35 × 106 km2, the area of mountain permafrost is ~ 0.30 × 106 km2 and the area of plateau permafrost is ~ 1.05 × 106 km2. The latitudinal permafrost is located in the northern part of northeastern China, and its area is ~ 0.24 × 106 km2. Additionally, some suggestions are proposed for future mapping of permafrost in China. Copyright © 2012 John Wiley & Sons, Ltd.

Near-Surface Permafrost Distribution Mapping Using Logistic Regression and Remote Sensing in Interior Alaska

A combination of binary logistic regression (BLR) and remote sensing techniques was used to generate a high-resolution spatially continuous near-surface (< 1.6 m) permafrost map. The BLR model was used to establish the relationship between vegetation type, aspect-slope, and permafrost presence; it predicted permafrost presence with an accuracy of 88%. Near-surface permafrost occupies 45% of the total vegetated area and 37% of the total study area. As less than 50% of the study area is underlain by near-surface permafrost, this distribution is characterized as "sporadic" for the study area.

Movement of trichloroethene in a discontinuous permafrost zone

At a site with discontinuous permafrost in Fairbanks, Alaska, releases of trichloroethene (TCE), an industrial solvent, have caused contamination of the groundwater. The objective of this study was to investigate the relationship between the migration pathway of the TCE groundwater plume and the distribution of the discontinuous permafrost at the site. The TCE plume configuration is substantially different than what regional hydrology trends would predict. Using GIS, we conducted a geostatistical analysis of field data collected during soil-boring installations and groundwater monitoring well sampling. With the analysis results, we constructed maps of the permafrost-table elevation (top of permafrost) and of the groundwater gradients and TCE concentrations from multiyear groundwater sampling events. The plume concentrations and groundwater gradients were overlain on the permafrost map to correlate permafrost locations with groundwater movement and the spatial distribution of TCE moving with groundwater. Correlation of the overlay maps revealed converging and diverging groundwater flow in response to the permafrost-table distribution, the absence of groundwater contamination in areas with a high permafrost-table elevation, and channeling of contaminants and water between areas of permafrost. In addition, we measured groundwater elevations in nested wells to quantify vertical gradients affecting TCE migration. At one set of nested wells down gradient from an area of permafrost we measured an upward vertical gradient indicating recharge of groundwater from the subpermafrost region of the aquifer causing dilution of the plume. The study indicates that the variable distribution of the permafrost is affecting the way groundwater and TCE move through the aquifer. Consequently, changes to the permafrost configuration due to thawing would likely affect both groundwater movement and TCE migration, and areas that were contaminant-free may become susceptible to contamination.

Remote sensing and field‐based mapping of permafrost distribution along the Alaska Highway corridor, interior Alaska

AbstractWe employed an integrated approach that combined remote sensing techniques with field measurements to predict the presence/absence of near‐surface permafrost in a section of the Alaska Highway corridor. We investigated the correlative relationships among vegetation type, topography, moss thickness, tussock condition and near‐surface permafrost in the study area. Analysis of moss thickness and active‐layer depth in low‐lying plains (slope &lt;8°) showed an inverse relationship in different vegetation classes. The maximum likelihood classification of remotely sensed data mapped 80% of the study area as covered with vegetation. We developed an empirical‐statistical (Binary Logistic Regression) model to establish the statistical relationship between surface variables and permafrost. The statistical relationships between the surface variables (vegetation, aspect and elevation classes) and permafrost were used within a spatial model to estimate the probability of permafrost presence at any given location (or pixel) in the study area. The statistical model yielded an overall classification accuracy of 80%. The spatial model mapped 62% of the total vegetated area as underlain by permafrost, including 99.5% of the scattered short spruce, 92.5% of the dense tall spruce, and 35.8% of the mixed spruce and deciduous vegetation classes. Comparison of our probabilistic permafrost map with an independently produced photo‐interpreted permafrost map showed 75% agreement for the continuously frozen class and very close agreement for the discontinuously frozen class. Copyright © 2010 John Wiley &amp; Sons, Ltd.

Estimating the extent of near‐surface permafrost using remote sensing, Mackenzie Delta, Northwest Territories

AbstractThe extent of near‐surface permafrost, or perennially frozen ground within 3 m of the surface, was estimated for the Mackenzie River delta by determining its association with riparian vegetation communities in the field, and by subsequently mapping these vegetation communities using SPOT‐5 data and the supervised maximum‐likelihood classification technique. Near‐surface permafrost was absent beneath willow–horsetail (Salix‐Equisetum) vegetation communities on point bars and alluvial islands throughout the delta and beneath horsetail (Equisetum) communities in the southern and central delta. Near‐surface permafrost was found beneath all other vegetation communities and land surface types. Multispectral SPOT‐5 data were classified with overall accuracies greater than 80 per cent. Using the remotely sensed vegetation community data, near‐surface permafrost was estimated to occur beneath 93 per cent, 95 per cent and 96 per cent of the land surface within the investigation areas of the southern, central and northern delta, respectively. In contrast to the most recent Permafrost Map of Canada, these results indicate that the Mackenzie Delta is part of the continuous permafrost zone. Copyright © 2009 Her Majesty the Queen in right of Canada. Published by John Wiley &amp; Sons, Ltd.

RELATIONSHIP BETWEEN DISCONTINUOUS FERMAFROST AND VAGETATION IN ALASKA

The purpose of this paper it to detect discontinuous permafrost in the subarctic taiga of Interior Alaska by using geophysical prospecting. Alaskan taiga is characterised by permafrost overlaid with an active layer. For shallow discontinuous permafrost mapping, we carriedout electorical resistivity sounding. The following results were obtained: beneath north-facing slopes, there is a continuous high electorical resistivity zone, the under boundary of which is almost flat through summer, and the thickness of which is between 10 and 20m. It follows from this that the high resistivity zone is almost equivalent to permafrost zone. Beneath south-facing slopes, two high resistivity zones are near surface and underground cavities at the depth of about 15m. It follows from these that the high resistivity zones are not equivalent to permafrost zones, these phenomena of near surface appear to depend on being dried through summer and on cavities of scree. And the permafrost and whose active layer influence the biology of the taiga. The second goal of this study was to describe the temporal variation of vegetation. The north-facing slopes have Black spruce-mosses woodland. The south-facing slopes have Aspen-birch forest, whose foot have Sphagnum mosses mire. The watershed have Dwarf shrubs.

Permafrost mapping of Northeast European Russia based on the period of climatic warming 1970-1995

Permafrost mapping of Northeast European Russia based on the period of climatic warming 1970-1995

Permafrost mapping of Northeast European Russia based on the periodof climatic warming 1970-1995

Permafrost mapping of Northeast European Russia based on the periodof climatic warming 1970-1995

Permafrost mapping: a review

Permafrost maps have developed over the last century from small line drawings showing the outer limits of the areas within which perennially frozen ground was known or supposed to exist, to large scale, multi-sheet, multi-faceted, complex earth-science documents. These show, in considerable detail, the estimated distribution of frozen ground, in terms of its spatial continuity, thickness, ground temperature and ground ice content. Other related geo-environmental information is commonly included along with the permafrost attributes. The key geocryological issues in permafrost mapping comprise definition, purpose, classification, data acquisition, and data storage and processing. The principal cartographic issues relate to map design, legend development and map production. The recent development of geographic information software (GIS) suitable for use on a desk-top computer allows the geocryologist to undertake many map compilation and production tasks directly. GIS software also allows the map compiler or map user to manipulate the data, layer by layer, and so create specialized maps for specific purposes. Computer storage and processing of permafrost data allows large volumes of data to be handled and, when combined with modelling techniques, allows these large volumes of data to be used in the compilation of maps. Integration of modelling techniques with GIS is a powerful tool for assessing the response of permafrost to a changing climate. Other research directions are noted.

Mapping of mountain permafrost using geophysical methods

Permafrost distribution in nonpolar mountain areas is strongly influenced by topo-graphical effects. Conditions therefore change within short distances and consequently the permafrost pattern is often very complex. Warm permafrost with temperatures between -2°C and 0°C is sensitive in terms of slope failures. It is also crucial to determine the lower permafrost boundary by geophysical means in order to calibrate models. Various geophysical methods have been applied to the mapping of mountain permafrost, including bottom temperature of the snow cover (BTS), refraction seismics, DC resistivity, ground penetrating radar (GPR), electromagnetic induction and radiometry. This paper gives an overview of investigations to map mountain permafrost distribution showing the potential of the modern use of geophysical methods. The two-dimensional DC resistivity tomography makes it possible to get an impression of internal structures. Electromagnetic induction methods showed good results, in particular the EM-31 for determining the permafrost distribution and the PROTEM to assess the overall permafrost thickness. Using passive microwave (11.4 GHz), the BTS, which is used as an indicator for the presence of permafrost, was measured. After ground surveys, an airborne test measurement from a helicopter was made. Traditional BTS measurements agreed very well with the BTS determined by radiometry.

PERMACLIM: a model for the distribution of mountain permafrost, based on climatic observations

In alpine environments at middle latitudes, the spatial distribution of mountain permafrost is strongly controlled by local climatic conditions, and specifically by snow cover. We present a physical model, PERMACLIM, which uses as input data a Climatic DataBase (CDB) and Digital Elevation Model (DEM). The model calculates the Mean Annual Ground Surface Temperature (MAGST) for each point of the DEM including the snow buffering effect according to the heat conduction theory, which uses both the CDB and field measurements of snow thermal characteristics. PERMACLIM provides a permafrost map based on MAGST values, where permafrost is designated as absent, probable or present, respectively, with MAGST values higher than 0 °C, ranging from 0 to −2 °C and lower than −2 °C. PERMACLIM can be improved by incorporating the ground surface temperatures during the snow-free period when solar radiation provides energy to the ground surface (PERMACLIM B). Both models have been tested in the “Passo del Foscagno” area, Italian Central Alps, comparing the output with the known permafrost distribution (obtained with geophysical investigations and borehole data) and with the permafrost distribution derived by Bottom Temperature of winter Snow cover (BTS). The model prediction of the permafrost distribution gives a good result compared with the permafrost distribution detected with geophysical investigations. Work to include snow redistribution by wind, snow melting and vegetation influences should further improve these results.

Mapping of permafrost on Vega Island, Antarctic Peninsula, using satellite images and aerial photography

AbstractThe work presented deals with detailed mapping of permafrost in Devil Bay, Vega Island, northeastern Antarctic Peninsula. Mapping of landforms and permafrost features within a periglacial plain was performed using high resolution visible satellite images and aerial photography. Two maps of permafrost were produced: one based on analysis and interpretation of visible satellite imagery and another on low-altitude aerial photography, both yielding similar results. The principles of morphogenesis were applied to map production, distinguishing both the syncryogenic and epicryogenic formations and each constitutive cryofacies. The interpretation of remote-sensing data allowed areas of occurrence of particular cryogenic processes to be defined. Remote sensing was found to be useful for permafrost mapping at both medium and large scales, and applicable for future extension to other regions in Antarctica.

Statistical modelling of mountain permafrost distribution: local calibration and incorporation of remotely sensed data

AbstractField mapping of mountain permafrost is laborious and is generally based on interpolation between point information. A spatial model that is based on elevation and a parameterization of solar radiation during summer is presented here. It allows estimation of permafrost distribution and can be calibrated locally, based on bottom temperature of snow (BTS) measurements or other indicators such as mapped features of permafrost creep. Local calibration makes this approach flexible and allows application in various mountain ranges. Model output consists of a continuous field of simulated BTS values that are subsequently divided into the classes ‘permafrost likely’, ‘permafrost possible’ and ‘no permafrost’ following the rules of thumb established for BTS field measurements in the Alps. Additionally, the simulated BTS values can be interpreted as a crude proxy for ground temperature regime and sensitivity to permafrost degradation. A map of vegetation abundance derived from atmospherically and topographically corrected satellite imagery was incorporated into this model to enhance the accuracy of the prediction. Based on the same corrected satellite image, a map of albedo was derived and used to calculate net short‐wave radiation, in an attempt to increase model accuracy. However, the statistical relationship with BTS did not improve. This is probably due to the correlation of short‐wave solar radiation with snow‐melt patterns or other factors of permafrost distribution which are being influenced differently by the introduction of albedo. Copyright © 2001 John Wiley &amp; Sons, Ltd.RÉSUMÉLa cartographie sur le terrain du pergélisol de montagne est un travail laborieux généralement basé e sur des interpolations entre des points pour lesquelles on possède des informations. Un modèle spatial basé sur l'altitude et le calcul de la radiation solaire est présenté ici. Il permet d'estimer la distribution du pergélisol et peut être calibré localement en utilisant des mesures de température à la base de la neige (BTS) et d'autres indications comme celles résultant de la cartographie des traces de creep du pergélisol. Une calibration locale rend cette approche flexible et permet son application dans différents milieux montagneux. Les données provenant du modèle se présentent comme un champ continu de valeurs BTS simulées qui sont par la suite divisées en classes de “pergélisol probable”, “pergélisol possible” et “pergélisol absent” suivant une règle empirique établie pour les mesures BTS dans les Alpes. En outre, les valeurs BTS simulées peuvent être interprétées comme donnant une approximation du régime de température du sol et de la fragilité à la dégradation du pergélisol.Une carte de l'abondance de la végétation dérivée d'images satellitaires corrigées pour l'atmosphère et la topographie a été incorporée dans ce modèle dans l'espoir d'augmenter la précision de la prédiction. Basée sur la même image satellitaire corrigée, une carte de l'albedo a été obtenue et utilisée pour calculer la radiation nette dans les ondes courtes pour essayer d'augmenter encore la précision du modèle. Toutefois la relation statistique avec les résultats obtenus par BTS n'a pas été augmentée. Cela est probablement dû à la corrélation existante entre la radiation solaire à courte longueur d'onde et le réseaux de fonte des neige, ainsi qu'à d'autres facteurs qui contrôlent la distribution du pergélisol en variant différemment d e l'albedo. Copyright © 2001 John Wiley &amp; Sons, Ltd.

Application of electrical imaging techniques for the investigation of natural dams: an example from the Thulagi Glacier Lake, Nepal

The Thulagi Glacier Lake in the Gorkha District of western Nepal was investigated by electrical resistivity tomography (ERT) to delineate buried glacier ice and permafrost zones within the dam. Data were processed using a 2-D inversion program and by finite-difference forward modelling. Interpretation of the processed electrical images indicates that the method can be used for detecting the buried ice and permafrost by virtue of their very high electrical resistivity values (&gt;20,000 Ohm.m and &gt;5.000 Ohm.m, respectively). The resistivity of permafrost seems to be strongly dependent on the material particle size: the finer the particle size the lower is the value of electrical resistivity. Water-saturated glacier sediments have values of electrical resistivity less than 3,000 Ohm.m. The ERT method was useful in mapping of buried glacier ice and permafrost as well as in differentiating other geological materials constituting the dam.

Permafrost mapping by transient electromagnetic method

Permafrost mapping by transient electromagnetic method

Permafrost mapping by transient electromagnetic method

Permafrost mapping by transient electromagnetic method