scholarly journals Wind driven snow conditions control the occurrence of contemporary marginal mountain permafrost in the Chic-Chocs Mountains, south-eastern Canada – a case study from Mont Jacques-Cartier

2016 ◽  
Author(s):  
Gautier Davesne ◽  
Daniel Fortier ◽  
Florent Dominé ◽  
James T. Gray
Keyword(s):  
Surface Temperature ◽  
Snow Cover ◽  
Ground Surface ◽  
Climatic Conditions ◽  
Eastern Canada ◽  
Ground Surface Temperature ◽  
South Eastern ◽  
Snow Distribution ◽  
Snow Conditions ◽  
The Impact

Abstract. We present data from Mont Jacques-Cartier, the highest summit in the Appalachians of south-eastern Canada, to demonstrate that the occurrence of contemporary permafrost body is necessarily associated with a very thin and wind-packed winter snow cover which brings local azonal topo-climatic conditions on the dome-shaped summit. The aims of this study was (i) to understand the snow distribution pattern and snow thermo-physical properties on the Mont Jacques-Cartier summit; and (ii) to investigate the impact of snow on the spatial distribution of the ground surface temperature (GST) using temperature sensors deployed over the summit. Results showed that above the local treeline, the summit is characterized by snow cover typically less than 30 cm thick due to the physiography and surficial geomorphology of the site and the strong westerly winds. The mean annual ground surface temperature (MAGST) below this thin and wind-packed snow cover was about −1 °C in 2013 and 2014, for the higher exposed sector of the summit characterised by a block-field or sporadic herbaceous cover. In contrast, for the gentle slopes covered with stunted spruce (krummholz), and for the steep leeward slope to the SE of the summit the MAGST was around 3 °C in 2013 and 2014.

scholarly journals Wind-driven snow conditions control the occurrence of contemporary marginal mountain permafrost in the Chic-Choc Mountains, south-eastern Canada: a case study from Mont Jacques-Cartier

2017 ◽  
Vol 11 (3) ◽  
pp. 1351-1370 ◽  
Author(s):  
Gautier Davesne ◽  
Daniel Fortier ◽  
Florent Domine ◽  
James T. Gray
Keyword(s):  
Surface Temperature ◽  
Snow Cover ◽  
Thermophysical Properties ◽  
Ground Surface ◽  
Climatic Conditions ◽  
Eastern Canada ◽  
Cold Surface ◽  
Ground Surface Temperature ◽  
South Eastern ◽  
The Impact

Abstract. We present data on the distribution and thermophysical properties of snow collected sporadically over 4 decades along with recent data of ground surface temperature from Mont Jacques-Cartier (1268 m a.s.l.), the highest summit in the Appalachians of south-eastern Canada. We demonstrate that the occurrence of contemporary permafrost is necessarily associated with a very thin and wind-packed winter snow cover which brings local azonal topo-climatic conditions on the dome-shaped summit. The aims of this study were (i) to understand the snow distribution pattern and snow thermophysical properties on the Mont Jacques-Cartier summit and (ii) to investigate the impact of snow on the spatial distribution of the ground surface temperature (GST) using temperature sensors deployed over the summit. Results showed that above the local treeline, the summit is characterized by a snow cover typically less than 30 cm thick which is explained by the strong westerly winds interacting with the local surface roughness created by the physiography and surficial geomorphology of the site. The snowpack structure is fairly similar to that observed on windy Arctic tundra with a top dense wind slab (300 to 450 kg m−3) of high thermal conductivity, which facilitates heat transfer between the ground surface and the atmosphere. The mean annual ground surface temperature (MAGST) below this thin and wind-packed snow cover was about −1 °C in 2013 and 2014, for the higher, exposed, blockfield-covered sector of the summit characterized by a sporadic herbaceous cover. In contrast, for the gentle slopes covered with stunted spruce (krummholz), and for the steep leeward slope to the south-east of the summit, the MAGST was around 3 °C in 2013 and 2014. The study concludes that the permafrost on Mont Jacques-Cartier, most widely in the Chic-Choc Mountains and by extension in the southern highest summits of the Appalachians, is therefore likely limited to the barren wind-exposed surface of the summit where the low air temperature, the thin snowpack and the wind action bring local cold surface conditions favourable to permafrost development.

scholarly journals Holocene paleoenvironmental reconstruction from deep ground temperatures: a comparison with paleoclimate derived from the δ18O record in an ice core from the agassiz Ice Cap, Canadian Arctic Archipelago

1991 ◽  
Vol 37 (126) ◽  
pp. 209-219 ◽  
Author(s):  
Alan E. Taylor
Keyword(s):  
Surface Temperature ◽  
Snow Cover ◽  
Ice Core ◽  
Canadian Arctic ◽  
Ground Surface ◽  
Temperature Profiles ◽  
Canadian Arctic Archipelago ◽  
Ground Surface Temperature ◽  
Ice Cap ◽  
Surface Temperatures

Abstract Changes in ground-surface temperature for the past few hundred years have been derived from deep temperature profiles at three wells in the northeastern Canadian Arctic Archipelago, and compared with the climatic history derived from the oxygen-isotope ratio 18O/16O measured in an ice core from the Agassiz Ice Cap, about 180-260 km to the east. Analysis of the ground-temperature profiles suggests that surface temperatures in the area decreased after the Little Climatic Optimum about 1000 years ago until the Little Ice Age (LIA). About 100 years ago, ground-surface temperatures appear to have increased by 2-5K to reach today’s values, while air temperatures increased by 2-3K, according to the isotope record. Part of the larger ground-surface temperature change may be due to other paleoenvironmental effects, such as an increase in snow cover coincident with the end of the LIA. The δ18O climatic record was successful in predicting the general features of the ground-temperature profiles observed at two of the sites, but not the third. There is contemporary evidence that surface temperatures at the latter site may be substantially modified by other environmental factors such as snow cover.

scholarly journals Modeling the impact of wintertime rain events on the thermal regime of permafrost

2011 ◽  
Vol 5 (4) ◽  
pp. 945-959 ◽  
Author(s):  
S. Westermann ◽  
J. Boike ◽  
M. Langer ◽  
T. V. Schuler ◽  
B. Etzelmüller
Keyword(s):  
Surface Temperature ◽  
Winter Season ◽  
Ground Surface ◽  
Field Measurements ◽  
Rain Water ◽  
Water Infiltration ◽  
Temperature Threshold ◽  
Ground Surface Temperature ◽  
Rain Events ◽  
The Impact

Abstract. In this study, we present field measurements and numerical process modeling from western Svalbard showing that the ground surface temperature below the snow is impacted by strong wintertime rain events. During such events, rain water percolates to the bottom of the snow pack, where it freezes and releases latent heat. In the winter season 2005/2006, on the order of 20 to 50% of the wintertime precipitation fell as rain, thus confining the surface temperature to close to 0 °C for several weeks. The measured average ground surface temperature during the snow-covered period is −0.6 °C, despite of a snow surface temperature of on average −8.5 °C. For the considered period, the temperature threshold below which permafrost is sustainable on long timescales is exceeded. We present a simplified model of rain water infiltration in the snow coupled to a transient permafrost model. While small amounts of rain have only minor impact on the ground surface temperature, strong rain events have a long-lasting impact. We show that consecutively applying the conditions encountered in the winter season 2005/2006 results in the formation of an unfrozen zone in the soil after three to five years, depending on the prescribed soil properties. If water infiltration in the snow is disabled in the model, more time is required for the permafrost to reach a similar state of degradation.

scholarly journals Modeling the impact of wintertime rain events on the thermal regime of permafrost

2011 ◽  
Vol 5 (3) ◽  
pp. 1697-1736 ◽  
Author(s):  
S. Westermann ◽  
J. Boike ◽  
M. Langer ◽  
T. V. Schuler ◽  
B. Etzelmüller
Keyword(s):  
Surface Temperature ◽  
Winter Season ◽  
Ground Surface ◽  
Field Measurements ◽  
Rain Water ◽  
Water Infiltration ◽  
Temperature Threshold ◽  
Ground Surface Temperature ◽  
Rain Events ◽  
The Impact

Abstract. In this study, we present field measurements and numerical process modeling from Western Svalbard showing that the ground surface temperature below the snow is impacted by strong wintertime rain events. During such events, rain water percolates to the bottom of the snow pack, where it freezes and releases latent heat. In the winter season 2005/2006, on the order of 20 to 50 % of the wintertime precipitation fell as rain, thus confining the surface temperature to close to 0 °C for several weeks. The measured average ground surface temperature during the snow-covered period is −0.6 °C, despite of a snow surface temperature of on average −8.5 °C. For the considered period, the temperature threshold below which permafrost is sustainable on long timescales is exceeded. We present a simplified model of rain water infiltration in the snow coupled to a transient permafrost model. While small amounts of rain have only minor impact on the ground surface temperature, strong rain events have a long-lasting impact. We show that consecutively applying the conditions encountered in the winter season 2005/2006 results in the formation of an unfrozen zone in the soil after three to five years, depending on the prescribed soil properties. If water infiltration in the snow is disabled in the model, more time is required for the permafrost to reach a similar state of degradation.

scholarly journals Holocene paleoenvironmental reconstruction from deep ground temperatures: a comparison with paleoclimate derived from the δ18O record in an ice core from the agassiz Ice Cap, Canadian Arctic Archipelago

1991 ◽  
Vol 37 (126) ◽  
pp. 209-219 ◽  
Author(s):  
Alan E. Taylor
Keyword(s):  
Surface Temperature ◽  
Snow Cover ◽  
Ice Core ◽  
Canadian Arctic ◽  
Ground Surface ◽  
Temperature Profiles ◽  
Canadian Arctic Archipelago ◽  
Ground Surface Temperature ◽  
Ice Cap ◽  
Surface Temperatures

AbstractChanges in ground-surface temperature for the past few hundred years have been derived from deep temperature profiles at three wells in the northeastern Canadian Arctic Archipelago, and compared with the climatic history derived from the oxygen-isotope ratio 18O/16O measured in an ice core from the Agassiz Ice Cap, about 180-260 km to the east. Analysis of the ground-temperature profiles suggests that surface temperatures in the area decreased after the Little Climatic Optimum about 1000 years ago until the Little Ice Age (LIA). About 100 years ago, ground-surface temperatures appear to have increased by 2-5K to reach today’s values, while air temperatures increased by 2-3K, according to the isotope record. Part of the larger ground-surface temperature change may be due to other paleoenvironmental effects, such as an increase in snow cover coincident with the end of the LIA.The δ18O climatic record was successful in predicting the general features of the ground-temperature profiles observed at two of the sites, but not the third. There is contemporary evidence that surface temperatures at the latter site may be substantially modified by other environmental factors such as snow cover.

scholarly journals Modeling the Temperature Field in the Ground with an Installed Slinky-Coil Heat Exchanger

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 4010
Author(s):  
Monika Gwadera ◽  
Krzysztof Kupiec
Keyword(s):  
Temperature Field ◽  
Heat Exchanger ◽  
Surface Temperature ◽  
Ground Surface ◽  
Heat Sources ◽  
Ground Surface Temperature ◽  
Coil Heat Exchanger ◽  
The Relationship ◽  
Temperature Responses ◽  
Coil Heat

In order to find the temperature field in the ground with a heat exchanger, it is necessary to determine temperature responses of the ground caused by heat sources and the influence of the environment. To determine the latter, a new model of heat transfer in the ground under natural conditions was developed. The heat flux of the evaporation of moisture from the ground was described by the relationship taking into account the annual amount of rainfall. The analytical solution for the equations of this model is presented. Under the conditions for which the calculations were performed, the following data were obtained: the average ground surface temperature Tsm = 10.67 °C, the ground surface temperature amplitude As = 13.88 K, and the phase angle Ps = 0.202 rad. This method makes it possible to easily determine the undisturbed ground temperature at any depth and at any time. This solution was used to find the temperature field in the ground with an installed slinky-coil heat exchanger that consisted of 63 coils. The results of calculations according to the presented model were compared with the results of measurements from the literature. The 3D model for the ground with an installed heat exchanger enables the analysis of the influence of miscellaneous parameters of the process of extracting or supplying heat from/to the ground on its temperature field.

Sign in / Sign up

Export Citation Format

Share Document