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Influence of surface and subsurface heterogeneity on observed borehole temperatures at a mountain permafrost site in the Upper Engadine, Swiss Alps  [PDF]
S. Schneider,M. Hoelzle,C. Hauck
The Cryosphere , 2012, DOI: 10.5194/tc-6-517-2012
Abstract: Compared to lowland (polar) regions, permafrost in high mountain areas occurs in a large variety of surface and subsurface materials and textures. This work presents an eight-year (2002–2010) data set of borehole temperatures for five different (sub-) surface materials from a high alpine permafrost area, Murtèl-Corvatsch, Switzerland. The influence of the material on the thermal regime was investigated by borehole temperature data, the temperature at the top of the permafrost (TTOP-concept) and the apparent thermal diffusivity (ATD). The results show that during the last eight years, material-specific temperature changes were more significant than climate-induced temperature trends. At coarse blocky, ice-rich sites, no changes in active layer depth were observed, whereas the bedrock and the fine-grained sites appear to be highly sensitive to changes in the microclimate. The results confirm that the presence and growth of ice as well as a thermally driven air circulation within the subsurface are the key factors for the occurence and preservation of alpine permafrost.
Influence of surface heterogeneity on observed borehole temperatures at a mountain permafrost site in the Upper Engadine, Swiss Alps  [PDF]
S. Schneider,M. Hoelzle,C. Hauck
The Cryosphere Discussions , 2011, DOI: 10.5194/tcd-5-2629-2011
Abstract: Compared to lowland (polar) regions, permafrost in high mountain areas occurs in a large variety of surface and subsurface material and texture. This work presents an eight-year (2002–2010) data set of borehole temperatures for five different (sub-) surface materials from a high alpine permafrost area, Murtel-Corvatsch, Switzerland. The influence of the material on the thermal regime was investigated by borehole temperature data, the TTOP-concept and the apparent thermal diffusivity (ATD). The results show that during the last eight years material specific temperature changes were more significant than for all boreholes consistent, climate-induced temperature trends. At coarse blocky, ice-rich sites no changes in active layer depth were observed, whereas the bedrock and the fine-grained sites appear to be highly sensitive to changes in the microclimate. The results confirm that the presence and growth of ice as well as a thermally driven air-circulation within the subsurface are the key factors for the occurence and preservation of alpine permafrost.
Brief Communication: "An inventory of permafrost evidence for the European Alps"  [PDF]
E. Cremonese,S. Gruber,M. Phillips,P. Pogliotti
The Cryosphere , 2011, DOI: 10.5194/tc-5-651-2011
Abstract: The investigation and modelling of permafrost distribution, particularly in areas of discontinuous permafrost, is challenging due to spatial heterogeneity, remoteness of measurement sites and data scarcity. We have designed a strategy for standardizing different local data sets containing evidence of the presence or absence of permafrost into an inventory for the entire European Alps. With this brief communication, we present the structure and contents of this inventory. This collection of permafrost evidence not only highlights existing data and allows new analyses based on larger data sets, but also provides complementary information for an improved interpretation of monitoring results.
Brief Communication: "An inventory of permafrost evidence for the European Alps"  [PDF]
E. Cremonese,S. Gruber,M. Phillips,P. Pogliotti
The Cryosphere Discussions , 2011, DOI: 10.5194/tcd-5-1201-2011
Abstract: The investigation and modelling of permafrost distribution, particularly in areas of discontinuous permafrost, is challenging due to spatial heterogeneity, remoteness of measurement sites and data scarcity. We have designed a strategy for standardizing different local data sets containing evidence of the presence or absence of permafrost into an inventory for the entire European Alps. With this brief communication, we present the structure and contents of this inventory. This collection of permafrost evidence not only highlights existing data and allows new analyses based on larger data sets, but also provides complementary information for an improved interpretation of monitoring results.
A statistical permafrost distribution model for the European Alps  [PDF]
L. Boeckli,A. Brenning,S. Gruber,J. Noetzli
The Cryosphere Discussions , 2011, DOI: 10.5194/tcd-5-1419-2011
Abstract: Permafrost distribution modeling in densely populated mountain regions is an important task to support the construction of infrastructure and for the assessment of climate change effects on permafrost and related natural systems. In order to analyze permafrost distribution and evolution on an Alpine-wide scale, one consistent model for the entire domain is needed. We present a statistical permafrost model for the entire Alps based on rock glacier inventories and rock surface temperatures. Starting from an integrated model framework, two different sub-models were developed, one for debris covered areas (debris model) and one for steep rock faces (rock model). For the debris model a generalized linear mixed-effect model (GLMM) was used to predict the probability of a rock glacier being intact as opposed to relict. The model is based on the explanatory variables mean annual air temperature (MAAT), potential incoming solar radiation (PISR) and the mean annual sum of precipitation (PRECIP), and achieves an excellent discrimination (area under the receiver-operating characteristic, AUROC = 0.91). Surprisingly, the probability of a rock glacier being intact is positively associated with increasing PRECIP for given MAAT and PISR conditions. The rock model was calibrated with mean annual rock surface temperatures (MARST) and is based on MAAT and PISR. The linear regression achieves a root mean square error (RMSE) of 1.6 °C. The final model combines the two sub-models and accounts for the different scales used for model calibration. Further steps to transfer this model into a map-based product are outlined.
Permafrost distribution in the European Alps: calculation and evaluation of an index map and summary statistics  [PDF]
L. Boeckli,A. Brenning,S. Gruber,J. Noetzli
The Cryosphere , 2012, DOI: 10.5194/tc-6-807-2012
Abstract: The objective of this study is the production of an Alpine Permafrost Index Map (APIM) covering the entire European Alps. A unified statistical model that is based on Alpine-wide permafrost observations is used for debris and bedrock surfaces across the entire Alps. The explanatory variables of the model are mean annual air temperatures, potential incoming solar radiation and precipitation. Offset terms were applied to make model predictions for topographic and geomorphic conditions that differ from the terrain features used for model fitting. These offsets are based on literature review and involve some degree of subjective choice during model building. The assessment of the APIM is challenging because limited independent test data are available for comparison and these observations represent point information in a spatially highly variable topography. The APIM provides an index that describes the spatial distribution of permafrost and comes together with an interpretation key that helps to assess map uncertainties and to relate map contents to their actual expression in the terrain. The map can be used as a first resource to estimate permafrost conditions at any given location in the European Alps in a variety of contexts such as research and spatial planning. Results show that Switzerland likely is the country with the largest permafrost area in the Alps, followed by Italy, Austria, France and Germany. Slovenia and Liechtenstein may have marginal permafrost areas. In all countries the permafrost area is expected to be larger than the glacier-covered area.
Permafrost distribution in the European Alps: calculation and evaluation of an index map and summary statistics  [PDF]
L. Boeckli,A. Brenning,S. Gruber,J. Noetzli
The Cryosphere Discussions , 2012, DOI: 10.5194/tcd-6-849-2012
Abstract: The objective of this study is the production of an Alpine Permafrost Index Map (APIM) covering the entire European Alps. A unified statistical model that is based on Alpine-wide permafrost observations is used for debris and bedrock surfaces across the entire Alps. The explanatory variables of the model are mean annual air temperatures, potential incoming solar radiation and precipitation. Offset terms were applied to make model predictions for topographic and geomorphic conditions that differ from the terrain features used for model fitting. These offsets are based on literature review and involve some degree of subjective choice during model building. The assessment of the APIM is challenging because limited independent test data are available for comparison and these observations represent point information in a spatially highly variable topography. The APIM provides an index that describes the spatial distribution of permafrost and comes together with an interpretation key that helps to assess map uncertainties and to relate map contents to their actual expression in terrain. The map can be used as a first resource to estimate permafrost conditions at any given location in the European Alps in a variety of contexts such as research and spatial planning. Results show that Switzerland likely is the country with the largest permafrost area in the Alps, followed by Italy, Austria, France and Germany. Slovenia and Liechtenstein may have marginal permafrost areas. In all countries the permafrost area is expected to be larger than the glacier-covered area. The permafrost index map with an approximate grid spacing of 30 m is available at the webpage of the Department of Geography, University of Zurich.
Optimisation of quasi-3D electrical resistivity imaging – application and inversion for investigating heterogeneous mountain permafrost  [PDF]
D. Schwindt,C. Kneisel
The Cryosphere Discussions , 2011, DOI: 10.5194/tcd-5-3383-2011
Abstract: This study aimed to optimise the application, efficiency and interpretability of quasi-3D resistivity imaging for investigating the heterogeneous permafrost distribution at mountain sites by a systematic forward modelling approach. A three dimensional geocryologic model, representative for most mountain permafrost settings, was developed. Based on this geocryologic model quasi-3D models were generated by collating synthetic orthogonal 2D arrays, demonstrating the effects of array types and electrode spacing on resolution and interpretability of the inversion results. The effects of minimising the number of 2D arrays per quasi-3D grid were tested by enlarging the spacing between adjacent lines and by reducing the number of perpendicular tie lines with regard to model resolution and loss of information value. Synthetic and measured quasi-3D models were investigated with regard to the lateral and vertical resolution, reliability of inverted resistivity values, the possibility of a quantitative interpretation of resistivities and the response of the inversion process on the validity of quasi-3D models. Results show that setups using orthogonal 2D arrays with electrode spacings of 2 m and 3 m are capable of delineating lateral heterogeneity with high accuracy and also deliver reliable data on active layer thickness. Detection of permafrost thickness, especially if the permafrost base is close to the penetration depth of the setups, and the reliability of absolute resistivity values emerged to be a weakness of the method. Quasi-3D imaging has proven to be a promising tool for investigating permafrost in mountain environments especially for delineating the often small-scale permafrost heterogeneity, and therefore provides an enhanced possibility for aligning permafrost distribution with site specific surface properties and morphological settings.
Population dynamics and production of crustacean zooplankton in two mountain lakes in the Italian Alps (Lake Paione Superiore and Lake Malghette).  [cached]
Marina MANCA,Patrizia COMOLI,Valeria LENCIONI
Journal of Limnology , 1999, DOI: 10.4081/jlimnol.1999.25
Abstract: We estimated production of three populations of zooplanktonic crustacea from two lakes in the Italian Alps sampled within the EC-Project MOLAR (ENV-CT95-0007) "Measuring and modelling the dynamic response of remote mountain lake ecosystems to environmental change" (Lake Paione Superiore) and the EC- Guideline 78/659 "On the amelioration and the protection of freshwaters suitable for fish life" (Lake Malghette). The former is a fishless lake, while the latter, in addition to the native Phoxynus phoxynus, hosts populations of Salmo trutta fario and Oncorhynchus mykiss. The Allen curve method was used to estimate production of Acanthodiaptomus denticornis and Daphnia longispina in Lake Malghette and of Cyclops abyssorum tatricus in Lake Paione Superiore. Values of daily production of the three populations are similar to those found by other Authors in oligotrophic and high mountain environments.
Home range dynamics of mountain hare (Lepus timidus) in the Swiss Alps
Anne-Sophie Genini-Gamboni,Francesco Bisi,Elisa Masseroni,Mosè Nodari
Hystrix : the Italian Journal of Mammalogy , 2009, DOI: 10.4404/hystrix-19.2-4425
Abstract: Little is known on the ecology and behaviour of alpine mountain hare (Lepus timidus). Between 1996 and 1997 we analysed by radiotracking the pattern of space use of 8 mountain hares from the Swiss Alps. We estimated home range size using both the kernel density estimator and the minimum convex polygon. We found smaller ranges (38 ha) compared to those reported for the species in boreal or arctic habitats, but similar to ranges in Scotland. Hares did not use a centre of major activity (core area) and showed high home range overlap, confirming their non-territorial behaviour. Smaller ranges were used during winter compared to the other seasons, whilst no difference in size was found between sexes. Riassunto Dinamica dell'uso dello spazio della lepre bianca (Lepus timidus) nelle Alpi Svizzere Le informazioni relative all'ecologia e al comportamento della lepre alpina (Lepus timidus) sono ad oggi scarse. In questo studio abbiamo analizzato l'utilizzo dello spazio di una popolazione di lepre bianca sulle Alpi Svizzere. Tra il 1996 e il 1997 sono stati marcati con redio collare 8 individui di lepre alpina. L'home range è stato calcolato utilizzando lo stimatore di densità kernel (KDE) ed il metodo del minimo poligono convesso (MCP). L'ampiezza degli home range (38 ha) è risultata inferiore a quella riportata per la specie in habitat boreali ed artici. ma simile a quella riscontrata in Scozia. All'interno dell home range non è stato rilevato alcun centro di maggiore attività (core area) ed è stata evidenziata una notevole sovrapposizione tra gli stessi, confermando la non territorialità della specie. Le aree frequentate in inverno sono risultate più piccole rispetto alle altre stagioni e non sono state riscontrate differenze tra i sessi.
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