A sensitivity study of factors influencing warm/thin permafrost in the Swiss Alps

AbstractAlpine permafrost distribution is controlled by a great number of climatic, topographic and soil-specific factors, including snow cover, which plays a major role. In this study, a one-dimensional finite-element numerical model was developed to analyze the influence of individual snow-specific and climatic factors on the ground thermal regime. The results indicate that the most important factor is snow depth. Snow depths below the threshold value of 0.6 m lack sufficient insulation to prevent low atmospheric temperatures from cooling the soil. The date of first winter snow insulation and variations in mean annual air temperature (MAAT) are also shown to be important. Delays in early-winter snow insulation and in summer snow disappearance are shown to be of approximately equal significance to the ground thermal conditions. Numerical modelling also indicates that the duration of effective thermal resistance of snow cover governs the slope of the linear dependency between MAAT and mean annual ground surface temperatures (MAGST). Consequently, the most direct effect of a long-term rise in air temperatures on ground temperatures is predicted under a thin snow cover with early snowmelt in spring and/or where a large change in the date of total snowmelt occurs, in response to atmospheric warming.

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Climatic influence on the composition of snow cover at Austre Okstindbreen, Norway, 1989 and 1990

Annals of Glaciology ◽

10.3189/1994aog19-1-1-6 ◽

1994 ◽

Vol 19 ◽

pp. 1-6 ◽

Cited By ~ 3

Author(s):

He Yuanqing ◽

Wilfred H. Theakstone

Keyword(s):

Snow Cover ◽

North Atlantic ◽

Early Summer ◽

Late Winter ◽

Crustal Material ◽

Air Masses ◽

The North ◽

Air Temperatures ◽

Winter Snow ◽

Marine Source

Winter snow cover at Austre Okstindbreen is influenced strongly by patterns of atmospheric circulation, and by air temperatures during precipitation. Differences of circulation over the North Atlantic and Scandinavia during the winters of 1988–89 and 1989–90 were reflected in the ionic and isotopic composition of snow that accumulated at the glacier. Early summer ablation did not remove, or smooth out, all the initial stratigraphic differences. In the first half of the 1988–89 winter, most air masses took a relatively short route between a marine source and Okstindan; late winter snowfalls were from air masses which had taken a longer continental route. The snow that accumulated in the first half of the 1989–90 winter was associated with air masses which had followed longer continental routes, and so brought higher concentrations of impurities from forests, lakes and crustal material. The ablation season began earlier in 1990 than in 1989, and summer winds and rain supplied more impurities to the snowpack surface.

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

10.5194/tc-2016-234 ◽

2016 ◽

Author(s):

Gonçalo Vieira ◽

Carla Mora ◽

Ali Faleh

Keyword(s):

Snow Cover ◽

North Africa ◽

Thermal Regime ◽

Ground Surface ◽

Cold Season ◽

Snow Accumulation ◽

Landsat 8 ◽

High Atlas ◽

Freeze Thaw ◽

Air Temperatures

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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New insights into the environmental drivers of the circumpolar ground thermal regime

10.5194/tc-2018-144 ◽

2018 ◽

Author(s):

Olli Karjalainen ◽

Miska Luoto ◽

Juha Aalto ◽

Jan Hjort

Keyword(s):

Thermal Regime ◽

Climatic Factors ◽

Global Climate ◽

Thermal Conditions ◽

Cold Climate ◽

The Arctic ◽

Environmental Drivers ◽

Active Layer Thickness ◽

Thermal Dynamics ◽

Air Temperatures

Abstract. The thermal dynamics of permafrost shape Earth surface systems and human activity in the Arctic and have implications to global climate. Improved understanding of the fine-scale variability in the circumpolar ground thermal regime is required to account for its sensitivity to changing climatic and geoecological conditions. Here, we statistically related circumpolar observations of mean annual ground temperature (MAGT) and active-layer thickness (ALT) to high-resolution (~1 km2) geospatial data to identify their key environmental drivers. The multivariate models fitted well to MAGT and ALT observations with average R2 values being ~0.94 and 0.78, respectively. Corresponding predictive performances in terms of root mean square error were ~1.31 °C and 87 cm. Freezing air temperatures were the main driver of MAGT in permafrost conditions while thawing temperatures dominated when permafrost was not present. ALT was most strongly related to solar radiation and precipitation with an important influence from soil properties. Our findings suggest that in addition to climatic factors, initial ground thermal conditions and local-scale topography-soil-driven variability need to be considered in order to realistically assess the impacts of climate change on cold-climate geoecosystems.

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The Input of the Climatic Factors in the Temperature Regime of Soils of Discontinuous Permafrost of Northern Taiga of Western Siberia

Dokuchaev Soil Bulletin ◽

10.19047/0136-1694-2017-87-39-54 ◽

2017 ◽

pp. 39-54

Author(s):

O. Yu. Goncharova ◽

G. V. Matyshak ◽

A. A. Bobrik ◽

D. G. Petrov ◽

M. O. Tarkhov ◽

...

Keyword(s):

Snow Cover ◽

Temperature Regime ◽

Western Siberia ◽

Climatic Factors ◽

Northern Taiga ◽

Cold Winter ◽

Air Temperatures ◽

Discontinuous Permafrost ◽

Long Time ◽

Soil Temperature Regime

The results of the four-year study of the temperature regime of soils of three common landscapes of northern taiga in Western Siberia, located in the area of discontinuous permafrost, are presented. The soils of lumpy peatlands are characterized by mild permafrost annual regime with very cold summer and moderately cold winter. Temperature regime of the forest soils may be characterized as cold long-time seasonally freezing mild with very cold summer and moderately cold winter. The soils of the investigated region are functioning in conditions of the narrow range of temperatures: at the depth of 20 cm for the soils of all of the landscapes, the temperatures vary within the range of -2.5 to 0°С. This occurs due to their high moisture, low thermal conductivity, specificities of snow cover regime and the freezing effect of permafrost rocks. Annual temperature soil indices are characterized by the weak correlation to the mean annual specificities of air temperature regime. We discovered the direct correlation of annual soil temperature regime and the dynamics of the snow cover (with average and maximal thickness, and thawing date), and with winter N-factor (surface temperature index), and accumulative positive temperatures. Since isolating activity of the vegetation is significantly lower than that of snow (summer N- factors 0.7-0.9), annual fluctuations of summer air temperatures will significantly affect the temperature regime of soils and geo-cryologic situation of the region in general.

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Transfer function models to quantify the delay between air and ground temperatures in thawed active layers

The Cryosphere Discussions ◽

10.5194/tcd-5-2935-2011 ◽

2011 ◽

Vol 5 (5) ◽

pp. 2935-2966

Author(s):

E. Zenklusen Mutter ◽

J. Blanchet ◽

M. Phillips

Keyword(s):

Transfer Function ◽

Response Times ◽

Ground Surface ◽

Phase Changes ◽

Swiss Alps ◽

Coarse Grained ◽

Ground Temperatures ◽

Air Temperatures ◽

Function Models ◽

Transfer Function Models

Abstract. Air temperatures influence ground temperatures with a certain delay, which increases with depth. Borehole temperatures measured at 0.5 m depth in Alpine permafrost and air temperatures measured at or near the boreholes have been used to model this dependency. Statistical transfer function models have been fitted to the daily difference series of air and ground temperatures measured at seven different permafrost sites in the Swiss Alps. The relation between air and ground temperature is influenced by various factors such as ground surface cover, snow depth, water or ground ice content. To avoid complications induced by the insulating properties of the snow cover and by phase changes in the ground, only the mostly snow-free summer period when the ground at 0.5 m depth is thawed has been considered here. All summers from 2006 to 2009 have been analysed, with the main focus on summer 2006. The results reveal that in summer 2006 daily air temperature changes influence ground temperatures at 0.5 m depth with a delay ranging from one to six days, depending on the site. The fastest response times are found for a very coarse grained, blocky rock glacier site whereas slower response times are found for blocky scree slopes with smaller grain sizes.

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Climatic influence on the composition of snow cover at Austre Okstindbreen, Norway, 1989 and 1990

Annals of Glaciology ◽

10.1017/s0260305500010909 ◽

1994 ◽

Vol 19 ◽

pp. 1-6 ◽

Cited By ~ 9

Author(s):

He Yuanqing ◽

Wilfred H. Theakstone

Keyword(s):

Snow Cover ◽

North Atlantic ◽

Early Summer ◽

Late Winter ◽

Crustal Material ◽

Air Masses ◽

The North ◽

Air Temperatures ◽

Winter Snow ◽

Marine Source

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

The Cryosphere ◽

10.5194/tc-11-1691-2017 ◽

2017 ◽

Vol 11 (4) ◽

pp. 1691-1705 ◽

Cited By ~ 8

Author(s):

Gonçalo Vieira ◽

Carla Mora ◽

Ali Faleh

Keyword(s):

Snow Cover ◽

North Africa ◽

Thermal Regime ◽

Ground Surface ◽

Cold Season ◽

Snow Accumulation ◽

Landsat 8 ◽

High Atlas ◽

Freeze Thaw ◽

Air Temperatures

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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Influence of some climatic elements on radon concentration in Saeva Dupka Cave, Bulgaria

International Journal of Speleology ◽

10.5038/1827-806x.49.3.2349 ◽

2020 ◽

Vol 49 (3) ◽

pp. 235-248

Author(s):

Peter Nojarov ◽

◽

Petar Stefanov ◽

Karel Turek ◽

◽

...

Keyword(s):

Snow Cover ◽

Water Content ◽

Radon Concentration ◽

Surface Soil ◽

Climatic Factors ◽

Tour Guides ◽

Leading Role ◽

Air Temperatures ◽

Significant Health ◽

Climatic Elements

This study reveals the influence of some climatic elements on radon concentration in Saeva Dupka Cave, Bulgaria. The research is based mainly on statistical methods. Radon concentration in the cave is determined by two main mechanisms. The first one is through penetration of radon from soil and rocks around the cave (present all year round, but has leading role during the warm half of the year). The second one is through thermodynamic exchange of air between inside of the cave and outside atmosphere (cold half of the year). Climatic factors that affect radon concentration in the cave are temperatures (air, surface, soil) and amount of water, expressed by precipitation or by volumetric water content in the soil. In the cold half of the year, an important factor is the duration and depth of snow cover. Statistical models and projections show that by the year 2070 CE radon concentration in the cave will increase. This increase will occur primarily in the warm half of the year due to the increase in outside air temperatures that will decrease thermodynamic exchange of air between the cave and the atmosphere. By the middle of the 21st century, it is expected that the studied area will no longer have a permanent snow cover and the temperature will remain the only factor for the increase of radon concentration in the cold half of the year. Water content in the soil and precipitation are important factors for radon concentration in the cave, but they have no significant trend and they are not expected to exert any influence in the next 50 years. The projected increase of radon concentration in Saeva Dupka Cave creates a serious risk for the health of the tour guides working there. That is why it is necessary to develop a plan to protect the health of the cave staff. On the other hand, the projected increase of radon concentration does not pose any significant health risk for the tourists visiting the cave.

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A Decade of Ground–Air Temperature Tracking at Emigrant Pass Observatory, Utah

Journal of Climate ◽

10.1175/jcli3808.1 ◽

2006 ◽

Vol 19 (15) ◽

pp. 3722-3731 ◽

Cited By ~ 47

Author(s):

Marshall G. Bartlett ◽

David S. Chapman ◽

Robert N. Harris

Keyword(s):

Solar Radiation ◽

Snow Cover ◽

Air Temperature ◽

Surface Air Temperature ◽

Incident Solar Radiation ◽

Ground Temperatures ◽

Temperature Tracking ◽

Air Temperatures ◽

Winter Snow ◽

A Minor

Abstract Observations of air and ground temperatures collected between 1993 and 2004 from Emigrant Pass Geothermal Climate Observatory in northwestern Utah are analyzed to understand the relationship between these two quantities. The influence of surface air temperature (SAT), incident solar radiation, and snow cover on surface ground temperature (SGT) variations are explored. SAT variations explain 94% of the variance in SGT. Incident solar radiation is the primary variable governing the remaining variance misfit and is significantly more important during summer months than winter months. A linear relationship between the ground–air temperature difference (ΔTsgt-sat) and solar radiation exists with a trend of 1.21 K/(100 W m−2); solar radiation accounts for 1.3% of the variance in SGT. The effects of incident solar radiation also account for the 2.47-K average offset in ΔTsgt-sat. During the winter, snow cover plays a role in governing SGT variability, but exerts only a minor influence on the annual tracking of ground and air temperatures at the site, accounting for 0.5% of the variance in SGT. These observations of the tracking of SGT and SAT confirm that borehole temperature changes mimic changes in SAT at frequencies appropriate for climatic reconstructions.

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