Ground temperature histories in eastern and central Canada from geothermal measurements: evidence of climatic change

Beltrami, Hugo; Jessop, A M; Mareschal, Jean‐Claude

doi:10.1016/0031-0182(92)90195-b

Cited by 66 publications

(40 citation statements)

References 34 publications

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“…This large magnitude of GST warming in Western Canada is confirmed by temperature anomalies from borehole temperature profiles measured in southwestern Manitoba and North Dakota (Gosnold et al 1997). Similar evidence of GST warming following a cold period with its minimum GST in the early to mid-19th century has been found from boreholes across northern North America: Quebec and Ontario (Beltrami et al 1992, Wang et al 1992, the midwestern United States (Harris & Chapman 1998), Manitoba (Guillou-Frottier et al 1998, and the Canadian Arctic (Beltrami & Taylor 1995).…”

Section: Introductionmentioning

confidence: 60%

“…The individual GSTHs were obtained by applying the FSI technique (Shen & Beck 1991, Beltrami et al 1992, Wang et al 1992, Shen et al 1995a, Pollack et al 1998, and a detailed description is given in Majorowicz & Safanda (1998a,b, 2001) and Majorowicz et al (1999). This technique assumes that heat transfer is by conduction alone through a 1-dimensional, possibly heterogeneous medium.…”

Section: The Inversion Methodsmentioning

confidence: 99%

“…is the cause of very low effective thermal conductivity (1.4 to 1.6 W mK -1 ) and low diffusivity (0.6 to 0.8 × 10 -6 m 2 s -1 ) observed here. Such low diffusivity values allow us to look for GST events relatively far back in time (a few centuries) with borehole temperature logs shallower than those from crystalline rocks in the Canadian Shield (Beltrami et al 1992). The temperature profiles were subjected to the inversion described by Shen et al (1995a).…”

Section: The Inversion Methodsmentioning

confidence: 99%

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Reconstruction of the surface warming history of western interior Canada from borehole temperature profiles and other climate information

Majorowicz¹,

Skinner²

2001

Clim. Res.

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Over the past several decades annual surface air temperature (SAT) warming in western interior Canada has been more than twice that of the global average. Inversions of the temperature profiles in boreholes throughout this large region provide evidence of anomalously high ground surface temperature (GST) warming trends between the mid-19th century and present. Previous studies have identified strong SAT/GST associations throughout this region for the 20th century. This analysis of the composite, century-scale, regional GST histories (GSTHs) is based on the deepest available borehole temperature logs from the Foreland Sedimentary Basin in western and northern Canada, east of the Cordillera. Although separated by almost 20°latitude, there is strong regional correlation (r = 0.98) between the GSTHs developed from northern (boreal forest) and southern (prairie grassland) boreholes. When filtered, the GSTHs of western Canada correlate strongly with the northern hemisphere (r = 0.80) and the Canadian Arctic (r = 0.86) high temporal resolution proxy climate histories. Strong correlation also exists between the prairie grassland GSTH curve and the tree-ring-based surface summer temperature history from the Columbia Icefield in the Canadian Rocky Mountains close to Athabasca Glacier (r = 0.95). These findings strongly suggest that the similar, but enhanced, SAT warming signal identified by GSTHs makes western interior Canada a strong indicator region of global warming.

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Section: Introductionmentioning

confidence: 60%

Section: The Inversion Methodsmentioning

confidence: 99%

Section: The Inversion Methodsmentioning

confidence: 99%

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Reconstruction of the surface warming history of western interior Canada from borehole temperature profiles and other climate information

Majorowicz¹,

Skinner²

2001

Clim. Res.

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“…The differences between the full gridpoint net and the perturbed subset are negligible in the context of the low frequency variability reproduced by the inverted histories; also, they are on the range of variability of typical methodological uncertainties in the SVD approach (e.g. Beltrami et al, 1992;Beltrami and Bourlon, 2004). Thus, Fig.…”

Section: Other Methodological Aspectsmentioning

confidence: 94%

Borehole climatology: a discussion based on contributions from climate modeling

et al. 2009

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Abstract. Progress in understanding climate variability through the last millennium leans on simulation and reconstruction efforts. Exercises blending both approaches present a great potential for answering questions relevant both for the simulation and reconstruction of past climate, and depend on the specific peculiarities of proxies and methods involved in climate reconstructions, as well as on the realism and limitations of model simulations. This paper explores research specifically related to paleoclimate modeling and borehole climatology as a branch of climate reconstruction that has contributed significantly to our knowledge of the low frequency climate evolution during the last five centuries.The text flows around three main issues that group most of the interaction between model and geothermal efforts: the use of models as a validation tool for borehole climate reconstructions; comparison of geothermal information and model simulations as a means of either model validation or inference about past climate; and implications of the degree of realism on simulating subsurface climate on estimations of future climate change.The use of multi-centennial simulations as a surrogate reality for past climate suggests that within the simplified reality of climate models, methods and assumptions in borehole reconstructions deliver a consistent picture of past climate evolution at long time scales. Comparison of model simulations and borehole profiles indicate that borehole temperatures are responding to past external forcing and that more realism in the development of the soil model components in climate models is desirable. Such an improved degree of Correspondence to: J. F. González-Rouco (fidelgr@fis.ucm.es) realism is important for the simulation of subsurface climate and air-ground interaction; results indicate it could also be crucial for simulating the adequate energy balance within climate change scenario experiments.

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“…In the case considered herein, the truncated singular value decomposition (SVD; see Lanczos, 1961, Varah, 1973, and Lawson and Hanson, 1974 is used to perform the inversion. This approach was introduced in the context of GST estimation by Beltrami et al (1992), and has since been a standard tool for analyzing borehole temperatures as paleoclimatic indicators. In this method, stabilization is achieved by keeping only the p largest singular values of M, using an appropriate threshold .…”

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confidence: 99%

Numerical studies on the Impact of the Last Glacial Cycle on recent borehole temperature profiles: implications for terrestrial energy balance

et al. 2014

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Abstract. Reconstructions of past climatic changes from borehole temperature profiles are important independent estimates of temperature histories over the last millennium. There remain, however, multiple uncertainties in the interpretation of these data as climatic indicators and as estimates of the changes in the heat content of the continental subsurface due to long-term climatic change. One of these uncertainties is associated with the often ignored impact of the last glacial cycle (LGC) on the subsurface energy content, and on the estimate of the background quasi steadystate signal associated with the diffusion of accretionary energy from the Earth's interior. Here, we provide the first estimate of the impact of the development of the Laurentide ice sheet on the estimates of energy and temperature reconstructions from measurements of terrestrial borehole temperatures in North America. We use basal temperature values from the data-calibrated Memorial University of Newfoundland glacial systems model (MUN-GSM) to quantify the extent of the perturbation to estimated steady-state temperature profiles, and to derive spatial maps of the expected impacts on measured profiles over North America. Furthermore, we present quantitative estimates of the potential effects of temperature changes during the last glacial cycle on the borehole reconstructions over the last millennium for North America. The range of these possible impacts is estimated using synthetic basal temperatures for a period covering 120 ka to the present day that include the basal temperature history uncertainties from an ensemble of results from the calibrated numerical model. For all the locations, we find that within the depth ranges that are typical for available boreholes (≈ 600 m), the induced perturbations to the steady-state temperature profile are on the order of 10 mW m −2 , decreasing with greater depths. Results indicate that site-specific heat content estimates over North America can differ by as much as 50 %, if the energy contribution of the last glacial cycle in those areas of North America that experienced glaciation is not taken into account when estimating recent subsurface energy changes from borehole temperature data.

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Ground temperature histories in eastern and central Canada from geothermal measurements: evidence of climatic change

Cited by 66 publications

References 34 publications

Reconstruction of the surface warming history of western interior Canada from borehole temperature profiles and other climate information

Reconstruction of the surface warming history of western interior Canada from borehole temperature profiles and other climate information

Borehole climatology: a discussion based on contributions from climate modeling

Numerical studies on the Impact of the Last Glacial Cycle on recent borehole temperature profiles: implications for terrestrial energy balance

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