Detection of mountain permafrost by combining conventional geophysical methods and thermal monitoring in the Retezat Mountains, Romania

Onaca, Alexandru; Ardelean, Adrian C.; Urdea, Petru; Ardelean, Florina; Sîrbu, Flavius

doi:10.1016/j.coldregions.2015.08.001

Cited by 28 publications

(28 citation statements)

References 46 publications

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“…At the site, the surface material is a boulderly matrix-supported deposit, with a pebbly-sandy matrix and no visible 30 voids. This limits the interpretation of a talus-ventilation related origin for the low GST and suggests conditions close to those described by Gądek and Kędzia (2008) in the Tatra Mountains and also by Onaca et al (2015) to the Tatras. It is also possible that the deposit is open work at depth, which could help explain the low temperatures, but this hypothesis lacks verification.…”

Section: Discussioncontrasting

confidence: 52%

“…Other authors have indicated snow redistribution by avalanches as an important factor promoting cooler ground and permafrost formation at the base of slopes, since snow lasts longer at those localities, mitigating ground surface 25 warming (Haeberli, 1975). Onaca et al (2015) indicate this as an important effect for the maintenance of permafrost in the Retezat Mountains (Romania), where permafrost occurs at sites with MAGST below 0 ºC, BTS lower than -3 ºC and ground freezing index higher than 600 degree-days.…”

Section: Discussionmentioning

confidence: 94%

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Ground surface temperatures indicate the presence of permafrost in North Africa (Djebel Toubkal, High Atlas, Morocco)

Vieira

Mora

Faleh

2016

Preprint

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Abstract. Relict and present-day periglacial activity have been reported in the literature for the upper reaches of the High Atlas mountains, the highest range in North Africa (Djebel Toubkal – 4,167 m a.s.l.). Lobate features in the Irhzer Ikbi South at 3,800 m a.s.l. have been previously interpreted as an active rock glacier, but no measurements of ground or air temperatures are known to exist for the area. In order to assess on the possible presence of permafrost, analyse data from June 2015 to June 2016 from two air temperature sites at 2,370 and 3,200 m a.s.l., and from four ground surface temperature (GST) sites at 3,200, 3,815, 3,980 and 4,160 m a.s.l. allowing to characterize conditions along an altitudinal gradient along the Oued Ihghyghaye valley to the summit of the Djebel Toubkal. GST were collected at 1-hour intervals and the presence of snow cover at the monitoring sites was validated using Landsat-8 and Sentinel-2 imagery. Two field visits allowed for logger installation and collection and for assessing the geomorphological features in the area. The results show that snow plays a major role on the thermal regime of the shallow ground, inducing important spatial variability. The lowest site at 3,210 m showed a regime characterized by frequent freeze-thaw cycles during the cold season but with a small number of days of snow. When snow sets, the ground remains isothermal at 0 °C and the thermal regime indicates the absence of permafrost. The highest sites at 3,980 and 4,160 m a.s.l. showed very frequent freeze-thaw cycles and a small influence of the snow cover on GST, reflecting the lack of snow accumulation due to the their wind-exposed settings in a ridge and in the summit plateau. The site located at 3,815 m in the Irhzer Ikbi South valley showed a stable thermal regime from December to March with GST varying from −4.5 to −6 °C, under a continuous snow cover. The site's location in a concave setting favours snow accumulation and lower incoming solar radiation due to the effect of a southwards ridge, favouring the maintenance of a thick snow pack. The stable and low GST are interpreted as a strong indicator of the probable presence of permafrost at this site, an interpretation which is supported by the presence of lobate and arcuate forms in the talus deposits. These results are still a first approach and observations through geophysics and boreholes are foreseen. This is the first time that probable permafrost is reported from temperature observations in the mountains of North Africa.

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Section: Discussioncontrasting

confidence: 52%

Section: Discussionmentioning

confidence: 94%

Ground surface temperatures indicate the presence of permafrost in North Africa (Djebel Toubkal, High Atlas, Morocco)

Vieira

Mora

Faleh

2016

Preprint

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“…The surface material is a bouldery matrix-supported deposit, with a pebbly-sandy matrix and no visible voids. This limits the interpretation of a talus-ventilation-related origin for the low GSTs and suggests conditions similar to those described by Gądek and Kędzia (2008) and by Onaca et al (2015) in the Tatra Mountains. In addition, the area around T3 has been observed to be one of the sites with the latest snow melt.…”

Section: Discussionmentioning

confidence: 69%

“…Onaca et al (2015) indicate this as an important effect for the maintenance of permafrost in the Retezat Mountains (Romania), where permafrost occurs at sites with MAGST below 0 • C, BTS lower than −3 • C and ground freezing index higher than 600 • days. Snow avalanche and rock and debris fall events have also been shown to be responsible for burial of snow and ice at the base of talus slopes, even at low altitudes (see for example Scapozza et al, 2011, or Kenner et al, 2017.…”

Section: Discussionmentioning

confidence: 99%

New observations indicate the possible presence of permafrost in North Africa (Djebel Toubkal, High Atlas, Morocco)

2017

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Abstract. Relict and present-day periglacial features have been reported in the literature for the upper reaches of the High Atlas mountains, which is the highest range in North Africa (Djebel Toubkal -4167 m a.s.l.). A lobate feature in the Irhzer Ikhibi south at 3800 m a.s.l. has been previously interpreted as an active rock glacier, but no measurements of ground or air temperatures are known to exist for the area. In order to assess the possible presence of permafrost, we analyse data from June 2015 to June 2016 from two air temperature measurement sites at 2370 and 3210 m a.s.l. and from four ground surface temperature (GST) sites at 3220, 3815, 3980 and 4160 m a.s.l. to characterize conditions along an altitudinal gradient along the Oued Ihghyghaye valley to the summit of the Djebel Toubkal. GSTs were collected at 1 h intervals, and the presence of snow cover at the monitoring sites was validated using Landsat 8 and Sentinel-2 imagery. Two field visits allowed for logger installation and collection and for assessing the geomorphological features in the area. The results show that snow plays a major role on the thermal regime of the shallow ground, inducing important spatial variability. The lowest site at 3220 m had a thermal regime characterized by frequent freeze-thaw cycles during the cold season but with few days of snow. When snow settled, the ground surface remained isothermal at 0 • C , indicating the absence of permafrost. The highest sites at 3980 and 4160 m a.s.l. showed very frequent freeze-thaw cycles and a small influence of the snow cover on GST, reflecting the lack of snow accumulation due to the wind-exposed settings on a ridge and on the summit plateau. The site located at 3815 m in the Irhzer Ikhibi south valley had a cold, stable thermal regime with GST varying from −4.5 to −6 • C from December to March, under a continuous snow cover.The site's location in a concave setting favours wind-driven snow accumulation and lower incoming solar radiation due to the shading effect of a ridge, inducing the conservation of a thick snow pack. The stable and low GSTs are interpreted as a strong indicator of the probable presence of permafrost at this site, which is an interpretation supported by the presence of lobate and arcuate features in the talus deposits. We present first results and further observations using geophysics, and borehole measurements are foreseen. This is the first time that probable permafrost has been reported from temperature observations in the mountains of North Africa.

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“…In general, research carried out on a regional scale in South America has been associated with regional mapping of Andean permafrost and inventories of rock glaciers using climatic characteristics that contribute to the formation of cryogenic sediments, and using satellite images either for statistical models of linear regression or methods of non‐linear detection . Other studies have sought to detect or interpret the presence of subterranean ice through indirect methods . However, here the Stepanek region is studied for this first time to provide a quantitative interpretation of active and inactive rock glaciers that may contain ground ice.…”

Section: Introductionmentioning

confidence: 99%

Periglacial water paths within a rock glacier‐dominated catchment in the Stepanek area, Central Andes, Mendoza, Argentina

Liaudat

Sileo

Dapeña

2020

Permafrost & Periglacial

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In the region of the Stepanek rock glacier (69 19 0 /69 26 0 W, 32 55 0 /32 59 0 S), in the Province of Mendoza, Argentina, seasonal hydrochemical monitoring was carried out between 2013 and 2017. This paper describes underground and surface water flow, and their hydrochemistry, and provides an overview of how groundwater interacts with the rock glacier. The cryogenic basin of the study area where the hydrological flows originate has a surface area of 11.5 km 2 . The Stepanek rock glacier fills the valley and its permafrost influences water flow. Isotopic analyses of surface ephemeral streams and groundwater were made. Characteristic, naturally occurring δ 2 H and δ 18 O signatures of these samples indicate strongly that they are fed from within permafrost from the rock glacier, in response to the degradation of permafrost and melting of ground ice. Elevated values of Ni 2+ , Cd 2+ and Zn 2+ were detected in the meltwater runoff. Due to lithological factors, the Andean periglacial environment may indicate altitudinal differences in the hydrogeochemical results. Our hydrogeochemical research allows the interpretation of different water flows, directly observed or indirectly deduced, which cross the rock glacier. The new information allows for the development of a new conceptual rock glacier model that includes different flow paths. It is expected that this will become more important due to ongoing climate change.

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Detection of mountain permafrost by combining conventional geophysical methods and thermal monitoring in the Retezat Mountains, Romania

Cited by 28 publications

References 46 publications

Ground surface temperatures indicate the presence of permafrost in North Africa (Djebel Toubkal, High Atlas, Morocco)

Ground surface temperatures indicate the presence of permafrost in North Africa (Djebel Toubkal, High Atlas, Morocco)

New observations indicate the possible presence of permafrost in North Africa (Djebel Toubkal, High Atlas, Morocco)

Periglacial water paths within a rock glacier‐dominated catchment in the Stepanek area, Central Andes, Mendoza, Argentina

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