scholarly journals Climate trends in northern Ontario and Quebec from borehole temperature profiles

2016 ◽  
Author(s):  
C. Pickler ◽  
H. Beltrami ◽  
J.-C. Mareschal
Keyword(s):  
Surface Temperature ◽  
Ground Surface ◽  
Ice Age ◽  
Climate Trends ◽  
James Bay ◽  
Northern Ontario ◽  
Ground Surface Temperature ◽  
Cooling Period ◽  
The Past ◽  
Discontinuous Permafrost

Abstract. The ground surface temperature histories of the past 500 years were reconstructed at 10 sites containing 18 boreholes in northeastern Canada. The boreholes, between 400 and 800 m deep, are located north of 51° N, and west and east of James Bay in northern Ontario and Quebec. We find that both sides of James Bay have experienced similar ground surface temperature histories with a warming of ~ 1–2 K for the last 150 years, similar to borehole reconstructions for the southern portion of the Superior Province and in agreement with available proxy data. A cooling period corresponding to the little ice age was found at only one site. Despite permafrost maps locating the sites in a region of discontinuous permafrost, the ground surface temperature histories suggest that the entire region is and was free of permafrost for the past 500 years. This could be the result of air surface temperature interpolation used in permafrost models being unsuitable to represent the spatial variability of ground temperatures along with an offset between ground and air surface temperatures due to the snow cover.

scholarly journals Climate trends in northern Ontario and Québec from borehole temperature profiles

2016 ◽  
Vol 12 (12) ◽  
pp. 2215-2227 ◽  
Author(s):  
Carolyne Pickler ◽  
Hugo Beltrami ◽  
Jean-Claude Mareschal
Keyword(s):  
Surface Temperature ◽  
Ground Surface ◽  
Ice Age ◽  
Climate Trends ◽  
James Bay ◽  
Northern Ontario ◽  
Ground Surface Temperature ◽  
Cooling Period ◽  
The Past ◽  
Discontinuous Permafrost

Abstract. The ground surface temperature histories of the past 500 years were reconstructed at 10 sites containing 18 boreholes in northeastern Canada. The boreholes, between 400 and 800 m deep, are located north of 51° N and west and east of James Bay in northern Ontario and Québec. We find that both sides of James Bay have experienced similar ground surface temperature histories with a warming of 1.51 ± 0.76 K during the period of 1850 to 2000, similar to borehole reconstructions for the southern portion of the Superior Province and in agreement with available proxy data. A cooling period corresponding to the Little Ice Age was found at only one site. Despite permafrost maps locating the sites in a region of discontinuous permafrost, the ground surface temperature histories suggest that the potential for permafrost was minimal to absent over the past 500 years. This could be the result of air surface temperature interpolation used in permafrost models being unsuitable to account for the spatial variability of ground temperatures along with an offset between ground and air surface temperatures due to the snow cover.

scholarly journals Past climate changes and permafrost depth at the Lake El'gygytgyn site: implications from data and thermal modeling

2013 ◽  
Vol 9 (1) ◽  
pp. 119-133 ◽  
Author(s):  
D. Mottaghy ◽  
G. Schwamborn ◽  
V. Rath
Keyword(s):  
Surface Temperature ◽  
Thermal Regime ◽  
Climate Changes ◽  
Ground Surface ◽  
Temperature Data ◽  
Ice Age ◽  
Drilling Process ◽  
Past Climate ◽  
Ground Surface Temperature ◽  
Recent Climate

Abstract. This study focuses on the temperature field observed in boreholes drilled as part of interdisciplinary scientific campaign targeting the El'gygytgyn Crater Lake in NE Russia. Temperature data are available from two sites: the lake borehole 5011-1 located near the center of the lake reaching 400 m depth, and the land borehole 5011-3 at the rim of the lake, with a depth of 140 m. Constraints on permafrost depth and past climate changes are derived from numerical simulation of the thermal regime associated with the lake-related talik structure. The thermal properties of the subsurface needed for these simulations are based on laboratory measurements of representative cores from the quaternary sediments and the underlying impact-affected rock, complemented by further information from geophysical logs and data from published literature. The temperature observations in the lake borehole 5011-1 are dominated by thermal perturbations related to the drilling process, and thus only give reliable values for the lowermost value in the borehole. Undisturbed temperature data recorded over more than two years are available in the 140 m deep land-based borehole 5011-3. The analysis of these observations allows determination of not only the recent mean annual ground surface temperature, but also the ground surface temperature history, though with large uncertainties. Although the depth of this borehole is by far too insufficient for a complete reconstruction of past temperatures back to the Last Glacial Maximum, it still affects the thermal regime, and thus permafrost depth. This effect is constrained by numerical modeling: assuming that the lake borehole observations are hardly influenced by the past changes in surface air temperature, an estimate of steady-state conditions is possible, leading to a meaningful value of 14 ± 5 K for the post-glacial warming. The strong curvature of the temperature data in shallower depths around 60 m can be explained by a comparatively large amplitude of the Little Ice Age (up to 4 K), with low temperatures prevailing far into the 20th century. Other mechanisms, like varying porosity, may also have an influence on the temperature profile, however, our modeling studies imply a major contribution from recent climate changes.

scholarly journals Simulating Active Layer Thaw in a Boreal Environment

2007 ◽  
Vol 60 (1) ◽  
pp. 9-17 ◽  
Author(s):  
Ming-ko Woo ◽  
Michael Mollinga ◽  
Sharon L. Smith
Keyword(s):  
Surface Temperature ◽  
Phase Change ◽  
Active Layer ◽  
Oil And Gas ◽  
Environmental Changes ◽  
Ground Surface ◽  
Ground Surface Temperature ◽  
Annual Variations ◽  
Discontinuous Permafrost ◽  
Boreal Environment

Abstract A large part of the boreal zone of the western Canadian Arctic is underlain by ice-rich discontinuous permafrost which when thawed, can lead to settlement of the ground surface that has implications for the integrity of northern infrastructure, including oil and gas pipelines. A simple yet physically-based model is desired to simulate thawing of the active layer in different materials commonly found along the Mackenzie Valley pipeline corridor. Stefan’s algorithm determines the phase change of soil moisture using ground surface temperature as the upper boundary condition and conduction to transfer heat to the freeze-thaw front. It is tested on a permafrost site near Wrigley, Northwest Territories, where the computed thaw penetration compares satisfactorily with field data. To further explore the effects of climate and soil types on active layer depth, three representative sites in the Mackenzie valley where ground surface temperatures are available were selected for simulation of ground thaw, under two summer conditions. Results of the simulation demonstrate the sensitivity of active layer thaw to (1) soil materials due to differential thermal properties, (2) moisture content, which largely controls the latent heat requirement for phase change, and (3) inter-annual variations in ground surface temperature. Given the strong potential for environmental changes in the vast boreal region, the model allows the active layer thaw responses to be easily assessed.

scholarly journals Thermal log analysis for recognition of ground surface temperature change and water movements

2007 ◽  
Vol 3 (1) ◽  
pp. 95-120 ◽  
Author(s):  
M. Verdoya ◽  
P. Chiozzi ◽  
V. Pasquale
Keyword(s):  
Surface Temperature ◽  
19Th Century ◽  
Ground Surface ◽  
Northern Italy ◽  
Ice Age ◽  
Joint Analysis ◽  
Measured Temperature ◽  
Surface Temperature Change ◽  
Ground Surface Temperature ◽  
The 19Th Century

Abstract. A joint analysis of surface air temperature series recorded at meteorological stations and temperature-depth profiles logged in near-by boreholes was performed to estimate conditions existing prior to the beginning of the instrumental record in central-northern Italy. The adopted method considers conductive and advective heat transport in a horizontally layered medium and provides simultaneous estimates of the pre-observational temperatures and the Darcy velocities. The reconstruction of the ground surface temperature history using an inversion method was performed for boreholes where hydrological disturbances to measured temperature logs were proved to be negligible. Both methods revealed generally coherent climatic changes in the whole investigated area. Climatic conditions were generally warm and comparable with the reference period 1960–1990. The absence of the Little Ice Age in the middle ages seems to be a generic feature of the climate in central-northern Italy. Climate change of the 19th century was generally insignificant with well balanced periods of cold and warmth. The investigated area became significantly colder only at the end of the 19th century. Cooling culminated around 1950 when it was replaced by rapid warming. Recent warming was not inferred only for one of the investigated holes. This discrepancy can be attributed to local environmental conditions.

scholarly journals Thermal log analysis for recognition of ground surface temperature change and water movements

2007 ◽  
Vol 3 (2) ◽  
pp. 315-324 ◽  
Author(s):  
M. Verdoya ◽  
P. Chiozzi ◽  
V. Pasquale
Keyword(s):  
Surface Temperature ◽  
19Th Century ◽  
Ground Surface ◽  
Northern Italy ◽  
Ice Age ◽  
Joint Analysis ◽  
Measured Temperature ◽  
Surface Temperature Change ◽  
Ground Surface Temperature ◽  
The 19Th Century

Abstract. A joint analysis of surface air temperature series recorded at meteorological stations and temperature-depth profiles logged in nearby boreholes was performed to estimate conditions existing prior to the beginning of the instrumental record in central-northern Italy. The adopted method considers conductive and advective heat transport in a layered medium and provides simultaneous estimates of the pre-observational temperatures and the Darcy velocities. The reconstruction of the ground surface temperature history using a generalised least-squares inversion method was performed for boreholes where hydrological disturbances to measured temperature logs were proved negligible. Both methods revealed generally coherent climatic changes in the whole investigated area. Climatic conditions were generally warm and comparable with the reference period 1960–1990. The absence of the Little Ice Age seems to be a generic feature of the climate in central-northern Italy. Climate change of the 19th century was generally insignificant with well-balanced periods of cold and warmth. The investigated area became significantly colder only at the end of the 19th century. Cooling culminated around 1950 when it was replaced by rapid warming. Recent warming was not inferred only for one of the investigated holes.

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.

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