Permafrost Degradation and Destabilization of Alpine Rockwalls: A Very Close Link in the Mont Blanc Massif

2013 ◽  
pp. 397-402
Author(s):  
Ludovic Ravanel ◽  
Philip Deline
Keyword(s):  
Permafrost Degradation ◽  
Close Link ◽  
Mont Blanc Massif

scholarly journals Évolution des parois rocheuses gelées de haute montagne sous forçage climatique

2020 ◽  
pp. 034
Author(s):  
Ludovic Ravanel ◽  
Florence Magnin ◽  
Xavi Gallach ◽  
Philip Deline
Keyword(s):  
Global Warming ◽  
High Altitude ◽  
Recent Work ◽  
Time Scales ◽  
Heat Waves ◽  
High Mountain ◽  
Permafrost Degradation ◽  
Geomorphological Processes ◽  
Different Time Scales ◽  
Mont Blanc Massif

Avec le réchauffement du climat, la dégradation du permafrost est à l'origine d'une intensification des processus géomorphologiques sur les versants de haute montagne. Dans les parois rocheuses, les écroulements se multiplient et leur volume augmente, posant des problèmes de sécurité non seulement à haute altitude (infrastructures, alpinistes), mais également pour les fonds de vallée. Cet article présente les travaux récemment menés dans le massif du Mont-Blanc sur la relation entre climat et écroulements à différentes échelles de temps, les effets des épisodes caniculaires et la répartition et l'évolution du permafrost de paroi. Under global warming, permafrost degradation tends to intensify geomorphological processes on high mountain slopes. In the perennially frozen rock walls, the number and volume of rockfalls is increasing, causing safety problems not only at high altitude (infrastructure, mountaineers) but also for the valleys. This article summarizes recent work carried out in the Mont-Blanc massif on the climate-rockfall relationship at different time scales, the effects of heat waves, and the distribution/evolution of rock wall permafrost.

scholarly journals Modelling rock wall permafrost degradation in the Mont Blanc massif from the LIA to the end of the 21st century

2017 ◽  
Vol 11 (4) ◽  
pp. 1813-1834 ◽  
Author(s):  
Florence Magnin ◽  
Jean-Yves Josnin ◽  
Ludovic Ravanel ◽  
Julien Pergaud ◽  
Benjamin Pohl ◽  
...  
Keyword(s):  
Climate Change ◽  
Air Temperature ◽  
21St Century ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Permafrost Degradation ◽  
Rock Wall ◽  
Exposed Rock ◽  
Warm Permafrost ◽  
Mont Blanc Massif

Abstract. High alpine rock wall permafrost is extremely sensitive to climate change. Its degradation has a strong impact on landscape evolution and can trigger rockfalls constituting an increasing threat to socio-economical activities of highly frequented areas; quantitative understanding of permafrost evolution is crucial for such communities. This study investigates the long-term evolution of permafrost in three vertical cross sections of rock wall sites between 3160 and 4300 m above sea level in the Mont Blanc massif, from the Little Ice Age (LIA) steady-state conditions to 2100. Simulations are forced with air temperature time series, including two contrasted air temperature scenarios for the 21st century representing possible lower and upper boundaries of future climate change according to the most recent models and climate change scenarios. The 2-D finite element model accounts for heat conduction and latent heat transfers, and the outputs for the current period (2010–2015) are evaluated against borehole temperature measurements and an electrical resistivity transect: permafrost conditions are remarkably well represented. Over the past two decades, permafrost has disappeared on faces with a southerly aspect up to 3300 m a.s.l. and possibly higher. Warm permafrost (i.e.  >   − 2 °C) has extended up to 3300 and 3850 m a.s.l. in N and S-exposed faces respectively. During the 21st century, warm permafrost is likely to extend at least up to 4300 m a.s.l. on S-exposed rock walls and up to 3850 m a.s.l. depth on the N-exposed faces. In the most pessimistic case, permafrost will disappear on the S-exposed rock walls at a depth of up to 4300 m a.s.l., whereas warm permafrost will extend at a depth of the N faces up to 3850 m a.s.l., but possibly disappearing at such elevation under the influence of a close S face. The results are site specific and extrapolation to other sites is limited by the imbrication of local topographical and transient effects.

scholarly journals Modelling rock wall permafrost degradation in the Mont Blanc massif from the LIA to the end of the 21<sup>st</sup> century

2016 ◽  
Author(s):  
Florence Magnin ◽  
Jean-Yves Josnin ◽  
Ludovic Ravanel ◽  
Julien Pergaud ◽  
Benjamin Pohl ◽  
...  
Keyword(s):  
Climate Change ◽  
Air Temperature ◽  
21St Century ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Permafrost Degradation ◽  
Rock Wall ◽  
Exposed Rock ◽  
Warm Permafrost ◽  
Mont Blanc Massif

Abstract. High alpine rock wall permafrost is extremely sensitive to climate change. Its degradation can trigger rock falls constituting an increasing threat to socio-economical activities of highly frequented areas. Understanding of permafrost evolution is therefore crucial. This study investigates the long-term evolution of permafrost in three vertical cross-sections of rock wall sites between 3160 and 4300 m a.s.l. in the Mont Blanc massif, since LIA steady-state conditions to 2100. Simulations are forced with air temperature time series, including two contrasted air temperature scenarios for the 21st century representing possible lower and upper boundaries of future climate change according to the most recent models and climate change scenarios. The model outputs for the current period (2010–2015) are evaluated against borehole temperature measurements and an electrical resistivity transect: permafrost conditions are remarkably well represented. Along the past two decades, permafrost has disappeared into the S-exposed faces up to 3300 m a.s.l., and possibly higher. Warm permafrost (i.e. > −2 °C) has extended up to 3300 and 3850 m a.s.l. in N and S-exposed faces, respectively. Along the 21st century, warm permafrost is likely to extent at least up to 4300 m a.s.l. into the S-exposed rock walls, and up to 3850 m a.s.l. at depth of the N-exposed faces. In the most pessimistic case, permafrost will disappear at depth of the S-exposed rock walls up to 4300 m a.s.l., whereas warm permafrost will extend at depth of the N faces up to 3850 m a.s.l., but could disappear at such elevation under the influence of a close S face. The results are site-specific and extrapolation to other sites is limited by the imbrication of the local topographical and transient effects. Shorter time-scale changes are not debatable due to limitations in the modelling approaches and future air temperature scenarios.

Merger regulation in Central and Eastern Europe: Evidence from Hungary, Romania and Slovenia

2002 ◽  
Vol 52 (3) ◽  
pp. 327-345 ◽  
Author(s):  
T. Kravtseniouk
Keyword(s):  
Eastern Europe ◽  
Central And Eastern Europe ◽  
Merger Control ◽  
Substantial Part ◽  
Economic Competition ◽  
Close Link ◽  
Case Study Methodology ◽  
Domestic Markets ◽  
Study Methodology

This paper shows the principal features of merger control in selected transition economies of Central and Eastern Europe (CEE), namely Hungary, Romania and Slovenia, by applying case study methodology. The presented findings are based on the analysis of Hungarian, Romanian and Slovenian competition law and merger rulings reached by the Competition Offices of these countries. A substantial part of the conclusions is drawn from a sample of 42 merger applications processed by the Office of Economic Competition of Hungary between 1994 and 2000. The results of empirical analysis demonstrate the considerable flexibility of merger control in the studied countries, its orientation towards the future of domestic markets and a close link with industrial policy. The paper also highlights the areas of interdependence of competition policy and transition and argues that merger control in the studied CEE countries may be regarded as currently adequate to the requirements imposed by transition.

MONITORING OF THE THERMOABRASIONAL AND ACCUMULATIVE COASTS NEAR THE UNDERWATER GAS PIPELINE ROUTE ACROSS THE BAYDARATSKAYA BAY, KARA SEA

2017 ◽  
Author(s):  
Nataliya Belova ◽  
Nataliya Belova ◽  
Alisa Baranskaya ◽  
Alisa Baranskaya ◽  
Osip Kokin ◽  
...  
Keyword(s):  
Thermal Regime ◽  
Storm Surges ◽  
Gas Pipeline ◽  
The Arctic ◽  
Yamal Peninsula ◽  
Permafrost Degradation ◽  
Nearshore Zone ◽  
Barrier Beach ◽  
Energy Dissipater ◽  
Pipeline Route

The coasts of Baydaratskaya Bay are composed by loose frozen sediments. At Yamal Peninsula accumulative coasts are predominant at the site where pipeline crosses the coast, while thermoabrasional coast are prevail at the Ural coast crossing site. Coastal dynamics monitoring on both sites is conducted using field and remote methods starting from the end of 1980s. As a result of construction in the coastal zone the relief morphology was disturbed, both lithodynamics and thermal regime of the permafrost within the areas of several km around the sites where gas pipeline crosses coastline was changed. At Yamal coast massive removal of deposits from the beach and tideflat took place. The morphology of barrier beach, which previously was a natural wave energy dissipater, was disturbed. This promoted inland penetration of storm surges and permafrost degradation under the barrier beach. At Ural coast the topsoil was disrupted by construction trucks, which affected thermal regime of the upper part of permafrost and lead to active layer deepening. Thermoerosion and thermoabrasion processes have activated on coasts, especially at areas with icy sediments, ice wedges and massive ice beds. Construction of cofferdams resulted in overlapping of sediments transit on both coasts and caused sediment deficit on nearby nearshore zone areas. The result of technogenic disturbances was widespread coastal erosion activation, which catastrophic scale is facilitated by climate warming in the Arctic.

CRYOGENIC DYNAMICS IN THE COASTAL ZONE OF THE LAPTEV AND EAST SIBERIAN SEAS

2017 ◽  
Author(s):  
Anatoly Gavrilov ◽  
Anatoly Gavrilov ◽  
Elena Pizhankova ◽  
Elena Pizhankova
Keyword(s):  
Coastal Zone ◽  
Permafrost Degradation

We consider the patterns of existence of thermo-abrasion, thermo-denudation and submarine permafrost degradation in the coastal zone of the Laptev and East Siberian seas. The key goal is to assess their role in changing the permafrost conditions along the coastal zone of a few tens of kilometers wide.

Uric Acid in Metabolic and Cerebrovascular Disorders: A Review

2020 ◽  
Vol 18 (6) ◽  
pp. 610-618
Author(s):  
Francesca Cortese ◽  
Pietro Scicchitano ◽  
Anna M. Cortese ◽  
Giovanni Meliota ◽  
Andrea Andriani ◽  
...  
Keyword(s):  
Metabolic Syndrome ◽  
Uric Acid ◽  
Cerebrovascular Disorders ◽  
Haemorrhagic Stroke ◽  
Cerebrovascular Diseases ◽  
Healthcare Research ◽  
Cochrane Library ◽  
Close Link ◽  
Mesh Terms ◽  
Active Inflammation

Background: Several studies showed a close link between metabolic syndrome (MetS), type 2 diabetes (T2DM) and cerebrovascular diseases. There is considerable debate regarding the role of uric acid (UA) as a risk factor in these conditions. Objective: The aim of this narrative review is to discuss the links between UA, MetS, T2DM and cerebrovascular disease. Methods: An extensive review has been conducted based on the scientific literature published in English, and indexed in MEDLINE (through PubMed), EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and Google Scholar from January to May 2019. Additional relevant studies published after the initial review were also considered during the period of June 2019-October 2019, during which, this manuscript was written. The Mesh Terms considered were: uric acid, antioxidant, oxidant, metabolic syndrome, diabetes, cerebrovascular diseases, stroke, haemorrhagic stroke, neurocognitive disorders, and their combinations. Results: The literature review shows a dose-dependent inflammatory action of UA, which occurs with serum concentrations >4 mg/dl (>0.24 mmol/l), representing one of the contributors to the chronic inflammatory process that underlies metabolic and cerebrovascular diseases. Conclusion: UA, which is associated with arterial hypertension and cardiovascular diseases, represents one of the indicators of oxidative homeostasis. Increasing concentrations represent a status of active inflammation which is observed with metabolic and cerebrovascular diseases.

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