Caracterización térmica de la capa activa de un glaciar rocoso en medio periglaciar de alta montaña mediterránea : El ejemplo del Corral del Veleta (Sierra Nevada, España)

Franch, Ferran Salvador; Ortíz, Antonio Gómez; Catarineu, Montserrat Salvà; Estremera, David Palacios

doi:10.18172/cig.1255

Cited by 16 publications

(13 citation statements)

References 10 publications

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“…For example, Salvador Franch et al (2011) indicate that the mean annual ground temperature in a shallow borehole with permafrost in the Sierra Nevada was 0.6 • C at 0.05 m depth, while the PERMOS network in Switzerland consistently shows MAGST below the values measured in the High Atlas (PERMOS, 2016). There is a clear altitudinal control on the MAGST, but topographically driven site-specific factors, such as high snow accumulation and lower potential annual solar radiation, affect the spatial pattern and lower the surface temperatures, as was observed at T3.…”

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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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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“…The central aim of this work is to provide a review and new data regarding present‐day activity of periglacial processes and their relationship with the ground thermal regime in different landforms across the Sierra Nevada (Table ). We update data and provide the most extensive and complete review of the thermal regime of a southern massif in Europe, complementing previous works …”

Section: Methodsmentioning

confidence: 99%

“…At the summits (3300–3400 m) MAAT is 0°C (2003–2013) and snow and frozen soil can persist, in an irregular manner that depends on the location, from early November to mid‐June. The warm season is very short and dry, with a mean monthly air temperature of 10–11°C in July and August at the summit level . These climatic conditions favor the existence of a periglacial belt from ca.…”

Section: Study Areamentioning

confidence: 99%

Monitoring permafrost and periglacial processes in Sierra Nevada (Spain) from 2001 to 2016

Gómez‐Ortiz

Oliva

Franch

et al. 2019

Permafrost & Periglacial

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Outside the Alps, the Sierra Nevada is probably the best studied European massif with respect to its past and current environmental dynamics. A multi‐approach research program started in the early 2000s focused on the monitoring of frozen ground conditions in this National Park. Here, we present data on the thermal state and distribution of permafrost and seasonal frozen ground in different sites across the highest areas of the massif. New results confirm the absence of widespread permafrost conditions, with seasonal frost prevailing above 2500 m. Small permafrost patches have been only detected in glaciated areas of the Veleta and Mulhacén cirques during the Little Ice Age at elevations of 3000–3100 m. The remnants of those glaciers are still preserved under the thick debris layer covering the cirque floors. Geomatic and geophysical surveying of a rock glacier existing in the Veleta cirque, together with the monitoring of soil temperature at different depths, have revealed permanently frozen conditions undergoing a process of degradation. In the rest of the massif, a seasonal frost regime prevails, even at the highest plateaus at 3300–3400 m, where annual soil temperatures average 2.5°C. The monitoring of soil temperatures in other different periglacial features has also revealed positive average values ranging between 2°C (inactive sorted‐circles) and 3–4°C (inactive and weakly active solifluction lobes). Consequently, we conclude that the present‐day climatic regime does not allow the existence of permafrost in the Sierra Nevada, and environmental dynamics is controlled by the intensity and duration of seasonal frost in the ground.

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“…a), allow us to conclude that this is a stabilized rock glacier owing to the fact that the frozen bodies housed in its interior tend to progressive degradation (Salvador‐Franch et al . ; Gómez‐Ortiz et al . ).…”

Section: Dynamics In the Sierra Nevada (Corral Del Veleta Rock Glacier)mentioning

confidence: 99%

Geomatics techniques applied to glaciers, rock glaciers, and ice patches in spain (1991–2012)

Blasco

Berenguer

Atkinson

et al. 2014

Geografiska Annaler: Series A, Physical Geography

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At present there is a wide variety of geomatic techniques available to determine the dynamics of glaciers, rock glaciers and ice patches. Between 1991 and 2012, different geomatic techniques – total station, global positioning system, close‐range photogrammetry and terrestrial laser scanner – were applied to monitor the movement of cryosphere landforms in the high mountains of the Iberian Peninsula. The applied techniques must be adapted to the dynamic conditions of cryospheric environments, and so there is no ideal general technique, and depending on the characteristics of the geomorphological structure to be studied, different geomatic techniques can be used. However, there are situations in which certain instruments cannot be used: global positioning system–real time kinematics shows difficulties when the presence of vertical walls cause a ‘multipath’ effect. The technique that provides the best results in each case must be chosen, although they can all give good results in measuring and monitoring geomorphological processes. This paper analyses the techniques used and results on vertical and horizontal changes of glaciers, rock glaciers and ice patches in the Sierra Nevada, Pyrenees and Picos de Europa, and differences among them by location and topoclimatic setting. All glaciers and rock glaciers show a thinning tendency and annual variations in the flow velocity. In addition to the specific dynamic analysis, the geomatic techniques can be used to detail scale and volume changes and perimeter of the analysed landforms.

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Caracterización térmica de la capa activa de un glaciar rocoso en medio periglaciar de alta montaña mediterránea : El ejemplo del Corral del Veleta (Sierra Nevada, España)

Cited by 16 publications

References 10 publications

New observations indicate the possible 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)

Monitoring permafrost and periglacial processes in Sierra Nevada (Spain) from 2001 to 2016

Geomatics techniques applied to glaciers, rock glaciers, and ice patches in spain (1991–2012)

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