scholarly journals Holocene Paleoenvironmental Reconstruction From Deep Ground Temperatures, Canadian Arctic Archipelago: A Comparison With Climatic Inferences From The δ18O Record Of Ice Cores

1990 ◽  
Vol 14 ◽  
pp. 359-360
Author(s):  
Alan E. Taylor
Keyword(s):  
Heat Flow ◽  
Surface Temperature ◽  
Ground Surface ◽  
Ice Cores ◽  
Ice Age ◽  
Measured Temperature ◽  
Paleoenvironmental Reconstruction ◽  
Ground Temperatures ◽  
Ice Cap ◽  
Subsurface Temperatures

The δ18O record from ice cores serves as a proxy paleoclimatic temperature record, through the association of isotopic ratio to air temperatures at time of precipitation. Climatic change may be preserved also as a signal in ground temperatures, not as a proxy indicator of past climate but as a direct consequence of the effect of past air temperature variations and associated physical processes at the ground surface. In the Canadian Arctic Archipelago, δ18O records are available from the Devon and Agassiz ice caps, and precision ground temperatures to depths of up to 1000 m are available from 40 petroleum exploration wells, about one third of which are suitable for paleoenvironmental reconstruction. There is an opportunity to compare these two methods of looking at the paleoenvironment, and to show how complementary they are to each other.Geothermal analysis is predicated on the fundamental hypothesis that the terrestrial heat flow, which arises largely from the decay of radioactive elements within the crust, does not vary measurably in the upper few km. But at many wells, the heat flow, calculated as the product of the measured temperature gradient and rock thermal conductivity, does vary systematically with depth in the well. While more random variations may be attributed to measurement errors, and corrections may be made for such known effects as local topography, the residual coherent “long wavelength” variation may be ascribed to effects arising from climate change.Can we, then, determine whether a particular temperature history is consistent with the geothermal record, or ideally, invert the geothermal data to reveal a record of past surface temperatures? Attempts with varying success at paleoclimatic reconstruction from ground temperatures have been reported in the literature (e.g. Lane, 1923; Hotchkiss and Ingersoll, 1934; Birch, 1948; Cermak, 1971; Vasseur and others, 1983; Lachenbruch and others, 1986) and from temperature profiles in ice sheets (e.g. Paterson, 1968; Weertman, 1968; Budd and Young, 1982).In this study, standard techniques in geothermics (e.g. Jaeger, 1965) have been used (1) to show the effect of any hypothesized surface paleotemperature model upon subsurface temperatures, or (2) on the hypothesis that the variation in heat flow is attributed to paleoclimatic effects, to derive a surface temperature model at each well that minimizes the variation in a statistical sense. The resolution of the method and limitations in our measured temperature and rock thermal conductivity data restrict the application of the second method to the past few hundred to one thousand years. The paper considers the first approach for the period 1 ka-10 kaB.p. at about a dozen wells and gives an example of the second approach at a well west of the Agassiz Ice Cap.Aproach (1). In studying the Devon Island ice core, Fisher and Koerner (1979) present a detailed record of the mean annual air temperature at the site throughout the Holocene, based on the δ18O record. A simplified time-temperature model of this record is applied to the ground temperature data set for the period 1 ka-10 ka B.P. Although the effect on the ground temperatures is only subtly perceptible, the model has the effect of reducing the apparent climatically-related curvature in the data, as reflected in an improvement in the standard deviation in the calculated heat flow profile by 5% to 30%. Hence, the geothermal record provides quantitative support for Holocene climatic information derived from the ice core record.Approach (2). This inversion technique is analogous to Paterson’s (1968) reconstruction of the surface temperature during the past century from a temperature profile taken in the small Meighen Ice Cap, Arctic Canada. A unique model is not obtained; rather, a small set of possible surface temperature variations consistent with the deeper subsurface temperatures is produced. Such modelling suggests that subsurface temperatures at a well 180 km west of the Agassiz Ice Cap are consistent with ground surface temperatures some 4–6 Κ lower at the well during the Little Ice Age; this is considerably more severe than the mean annual air temperatures projected from the δ18O record at Agassiz. It is possible that the large increase in ground surface temperature at the wellsite since the Little Ice Age may be attributed to some climatically-related phenomena such as increased incidence of snow cover coherent with the changing climate. A well on Devon Island is not deep enough for a comparison to that ice cap.The oxygen isotope data provide a valuable estimate of Holocene climate with which to correct ground temperature data for terrestrial heat flow, or other studies. However, examination of the signal of more recent events suggests that ground temperatures may be considerably modified by associated transient phenomena such as snow cover, vegetation, etc. Hence, one would expect that such a Holo¬cene correction might either understate or overstate the actual experience of the ground surface at a site.

scholarly journals Holocene Paleoenvironmental Reconstruction From Deep Ground Temperatures, Canadian Arctic Archipelago: A Comparison With Climatic Inferences From The δ18O Record Of Ice Cores

1990 ◽  
Vol 14 ◽  
pp. 359-360
Author(s):  
Alan E. Taylor
Keyword(s):  
Heat Flow ◽  
Surface Temperature ◽  
Ground Surface ◽  
Ice Cores ◽  
Ice Age ◽  
Measured Temperature ◽  
Paleoenvironmental Reconstruction ◽  
Ground Temperatures ◽  
Ice Cap ◽  
Subsurface Temperatures

The δ18O record from ice cores serves as a proxy paleoclimatic temperature record, through the association of isotopic ratio to air temperatures at time of precipitation. Climatic change may be preserved also as a signal in ground temperatures, not as a proxy indicator of past climate but as a direct consequence of the effect of past air temperature variations and associated physical processes at the ground surface. In the Canadian Arctic Archipelago, δ18O records are available from the Devon and Agassiz ice caps, and precision ground temperatures to depths of up to 1000 m are available from 40 petroleum exploration wells, about one third of which are suitable for paleoenvironmental reconstruction. There is an opportunity to compare these two methods of looking at the paleoenvironment, and to show how complementary they are to each other. Geothermal analysis is predicated on the fundamental hypothesis that the terrestrial heat flow, which arises largely from the decay of radioactive elements within the crust, does not vary measurably in the upper few km. But at many wells, the heat flow, calculated as the product of the measured temperature gradient and rock thermal conductivity, does vary systematically with depth in the well. While more random variations may be attributed to measurement errors, and corrections may be made for such known effects as local topography, the residual coherent “long wavelength” variation may be ascribed to effects arising from climate change. Can we, then, determine whether a particular temperature history is consistent with the geothermal record, or ideally, invert the geothermal data to reveal a record of past surface temperatures? Attempts with varying success at paleoclimatic reconstruction from ground temperatures have been reported in the literature (e.g. Lane, 1923; Hotchkiss and Ingersoll, 1934; Birch, 1948; Cermak, 1971; Vasseur and others, 1983; Lachenbruch and others, 1986) and from temperature profiles in ice sheets (e.g. Paterson, 1968; Weertman, 1968; Budd and Young, 1982). In this study, standard techniques in geothermics (e.g. Jaeger, 1965) have been used (1) to show the effect of any hypothesized surface paleotemperature model upon subsurface temperatures, or (2) on the hypothesis that the variation in heat flow is attributed to paleoclimatic effects, to derive a surface temperature model at each well that minimizes the variation in a statistical sense. The resolution of the method and limitations in our measured temperature and rock thermal conductivity data restrict the application of the second method to the past few hundred to one thousand years. The paper considers the first approach for the period 1 ka-10 kaB.p. at about a dozen wells and gives an example of the second approach at a well west of the Agassiz Ice Cap. Aproach (1). In studying the Devon Island ice core, Fisher and Koerner (1979) present a detailed record of the mean annual air temperature at the site throughout the Holocene, based on the δ18O record. A simplified time-temperature model of this record is applied to the ground temperature data set for the period 1 ka-10 ka B.P. Although the effect on the ground temperatures is only subtly perceptible, the model has the effect of reducing the apparent climatically-related curvature in the data, as reflected in an improvement in the standard deviation in the calculated heat flow profile by 5% to 30%. Hence, the geothermal record provides quantitative support for Holocene climatic information derived from the ice core record. Approach (2). This inversion technique is analogous to Paterson’s (1968) reconstruction of the surface temperature during the past century from a temperature profile taken in the small Meighen Ice Cap, Arctic Canada. A unique model is not obtained; rather, a small set of possible surface temperature variations consistent with the deeper subsurface temperatures is produced. Such modelling suggests that subsurface temperatures at a well 180 km west of the Agassiz Ice Cap are consistent with ground surface temperatures some 4–6 Κ lower at the well during the Little Ice Age; this is considerably more severe than the mean annual air temperatures projected from the δ18O record at Agassiz. It is possible that the large increase in ground surface temperature at the wellsite since the Little Ice Age may be attributed to some climatically-related phenomena such as increased incidence of snow cover coherent with the changing climate. A well on Devon Island is not deep enough for a comparison to that ice cap. The oxygen isotope data provide a valuable estimate of Holocene climate with which to correct ground temperature data for terrestrial heat flow, or other studies. However, examination of the signal of more recent events suggests that ground temperatures may be considerably modified by associated transient phenomena such as snow cover, vegetation, etc. Hence, one would expect that such a Holo¬cene correction might either understate or overstate the actual experience of the ground surface at a site.

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 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 Borehole temperatures reveal details of 20th century warming at Bruce Plateau, Antarctic Peninsula

2012 ◽  
Vol 6 (3) ◽  
pp. 675-686 ◽  
Author(s):  
V. Zagorodnov ◽  
O. Nagornov ◽  
T. A. Scambos ◽  
A. Muto ◽  
E. Mosley-Thompson ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Antarctic Peninsula ◽  
Accumulation Rate ◽  
Ice Cores ◽  
Temperature History ◽  
Mean Annual Temperature ◽  
Measured Temperature ◽  
Climate Trends ◽  
Cold Temperatures ◽  
Reconstructed Surface

Abstract. Two ice core boreholes of 143.18 m and 447.73 m (bedrock) were drilled during the 2009–2010 austral summer on the Bruce Plateau at a location named LARISSA Site Beta (66°02' S, 64°04' W, 1975.5 m a.s.l.). Both boreholes were logged with thermistors shortly after drilling. The shallow borehole was instrumented for 4 months with a series of resistance thermometers with satellite uplink. Surface temperature proxy data derived from an inversion of the borehole temperature profiles are compared to available multi-decadal records from weather stations and ice cores located along a latitudinal transect of the Antarctic Peninsula to West Antarctica. The LARISSA Site Beta profiles show temperatures decreasing from the surface downward through the upper third of the ice, and warming thereafter to the bed. The average temperature for the most recent year is −14.78°C (measured at 15 m depth, abbreviated T15). A minimum temperature of −15.8°C is measured at 173 m depth, and basal temperature is estimated to be −10.2°C. Current mean annual temperature and the gradient in the lower part of the measured temperature profile have a best fit with an accumulation rate of 1.9×103 kg m−2 a−1 and basal heat flux (q) of 88 mW m−2, if steady-state conditions are assumed. However, the mid-level temperature variations show that recent temperature has varied significantly. Reconstructed surface temperatures (Ts=T15) over the last 200 yr are derived by an inversion technique (Tikhonov and Samarskii, 1990). From this, we find that cold temperatures (minimum Ts=−16.2°C) prevailed from ~1920 to ~1940, followed by a gradual rise of temperature to −14.2°C around 1995, then cooling over the following decade and warming in the last few years. The coldest period was preceded by a relatively warm 19th century at T15≥−15°C. To facilitate regional comparisons of the surface temperature history, we use our T15 data and nearby weather station records to refine estimates of lapse rates (altitudinal, adjusted for latitude: Γa(l)). Good temporal and spatial consistency of Γa(l) over the last 35 yr are observed, implying that the climate trends observed here are regional and consistent over a broad altitude range.

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.

Assessing Arctic Ground Surface Temperatures from Borehole Temperatures and Paleoclimatic Model Simulations

2021 ◽  
Author(s):  
Hugo Beltrami ◽  
Fracisco José Cuesta-Valero ◽  
Almudena García-García ◽  
Stephan Gruber ◽  
Fernando Jaume-Santero
Keyword(s):  
Surface Temperature ◽  
Ground Surface ◽  
Phase Iii ◽  
The Arctic ◽  
Depth Range ◽  
Model Simulations ◽  
Ground Temperatures ◽  
Surface Temperatures ◽  
Intercomparison Project ◽  
Borehole Temperature

<p>The surface temperature response to changes in our planet’s external forcing is larger at higher latitudes, a phenomenon known as polar amplification. The Arctic amplification has been particularly intense during the last century, with arctic-wide paleoclimatic reconstructions and state-of-the-art model simulations revealing a twofold arctic warming in comparison with the average global temperature increase. As a consequence, Arctic ground temperatures respond with rapid warming, but this response varies with snow cover and permafrost processes. Thus, changes in arctic ground temperatures are difficult to reconstruct from data, and to simulate in climate models.</p><p>Here, we reconstruct the ground surface temperature histories of 120 borehole temperature profiles above 60ºN for the last 400 years. Past surface temperature evolution from each profile was estimated using a Perturbed Parameter Inversion approach based on a singular value decomposition method. Long-term surface temperature climatologies (circa 1300 and 1700 CE) and quasi-steady state heat flow are also estimated from linear regression through the depth range 200 to 300 m of each borehole temperature profile. The retrieved temperatures are assessed against simulated ground surface temperatures from five Past Millennium and five Historical experiments from the Paleoclimate Modelling Intercomparison Project Phase III (PMIP3), and the fifth phase of the Coupled Model Intercomparison Project (CMIP5) archives, respectively.</p><p>Preliminary results from borehole estimates and PMIP3/CMIP5 simulations reveal that changes in recent Arctic ground temperatures vary spatially and are related to each site’s earlier thermal state of the surface. The magnitudes of ground warming from data and simulations differ with large discrepancies among models. As a consequence, a better understanding of freezing processes at and below the air-ground interface is necessary to interpret subsurface temperature records and global climate model simulations in the Arctic.</p>

scholarly journals A 1000 year climate ice-core record from the Guliya ice cap, China: its relationship to global climate variability

1995 ◽  
Vol 21 ◽  
pp. 175-181 ◽  
Author(s):  
L. G. Thompson ◽  
E. Mosley-Thompson ◽  
M.E. Davis ◽  
P.N. Lin ◽  
J. Dai ◽  
...  
Keyword(s):  
Global Climate ◽  
Monsoon Season ◽  
Eastern China ◽  
Ice Core ◽  
Ice Cores ◽  
Ice Age ◽  
Ice Cap ◽  
Western Kunlun ◽  
Ice Core Record ◽  
Western Side

In 1992, an American-Chinese expedition successfully recovered three ice cores (308.6, 93.2 and 34.5m) from the Guliya ice cap (summit 6710 m a.s.l) in the far western Kunlun on the Qinghai–Tibetan Plateau, China. Guliya resembles a “polar” icecap with 10 m, 200 m and basal temperatures of –15.6°, –5.9° and –2.1°C, respectively. The 308.6 m core to bedrock is the longest ice core retrieved from an elevation greater than 4000 m a.s.l. and provides the first ice-core history from the western side of the Qinghai Plateau. The Plateau experiences a pronounced annual precipitation cycle during which 70–80% of annual total precipitation falls in the summer monsoon season. This leads to a marked visible stratigraphy in the glaciers which allows accurate dating of the ice cores and reconstruction of the net mass accumulation. This paper presents (1) the results of the geophysical program to determine ice thickness, ice flow and surface topography, (2) an assessment of net accumulation from stake measurements, snow pits and shallow core samples, and (3) the analyses of the upper 100 m of the 308.6 m core which provide a 1000 year history, including the ‘“Little Ice Age”, which is compared with Chinese historical records. Extended periods of positive accumulation on Guliya are closely contemporaneous with dry periods in eastern China. A trans-Pacific teleconnection is suggested by the strong temporal coherence between extended wet and dry phases on Guliya and on the Quelccaya ice cap, Peru.

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.

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