Air‐ground temperature coupling and subsurface propagation of annual temperature signals

Smerdon, Jason E.; Pollack, Henry N.; Čermák, Vladimír; Enz, John W.; Krešl, Milan; Šаfanda, Jan; Wehmiller, John F.

doi:10.1029/2004jd005056

Cited by 108 publications

(113 citation statements)

References 59 publications

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“…These records have most widely been used to estimate past temperature changes, but can also be used as estimates of past energy fluxes at the land surface. These latter reconstructions are possibly less vulnerable to processes that could potentially interfere with the coupling of surface air temperatures (SATs) and ground surface temperatures (GSTs), which have been discussed extensively in the literature (e.g., Beltrami, 1996;Schmidt et al, 2001;Beltrami and Kellman, 2003;Stieglitz et al, 2003;Bartlett et al, 2004Bartlett et al, , 2005Smerdon et al, 2003Smerdon et al, , 2004Smerdon et al, , 2006Smerdon et al, , 2009Demetrescu et al, 2007). In other words, subsurface heat storage Q s is independent of any surface temperature association.…”

Section: H Beltrami Et Al: Glacial Cycle Impactmentioning

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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Section: H Beltrami Et Al: Glacial Cycle Impactmentioning

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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“…However, questions regarding changes in the relationship between air and ground temperatures have prompted detailed investigations often in combination with other meteorological parameters (e.g. Baker and Ruschy, 1993;Putnam and Chapman, 1996;Smerdon et al, 2003Smerdon et al, , 2004Smerdon et al, , 2006Bartlett et al, 2006;Chudinova et al, 2006;Stieglitz and Smerdon, 2007). These studies have found that variations in air and ground temperatures generally track each other over the time period of study.…”

Section: Introductionmentioning

confidence: 99%

Variations in air and ground temperature and the POM-SAT model: results from the Northern Hemisphere

Harris

2007

Clim. Past

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Abstract. The POM-SAT model for comparing air and ground temperatures is based on the supposition that surface air temperature (SAT) records provide a good prediction of thermal transients in the shallow subsurface of the Earth. This model consists of two components, the forcing function and an initial condition, termed the pre-observational mean (POM). I explore the sensitivity of this model as a function of forcing periods at time scales appropriate for climate reconstructions. Synthetic models are designed to replicate comparisons between borehole temperatures contained in the global database of temperature profiles for climate reconstructions and gridded SAT data. I find that the root mean square (RMS) misfit between forcing functions and transient temperature profiles in the subsurface are sensitive to periods longer than about 50 years, are a maximum when the period and the 150-year time series are equal and then decreases for longer periods. The magnitude of the POM is a robust parameter for periods equal to or shorter than the length of this time series. At longer periods there is a tradeoff between the amplitude of the forcing function and the POM. These tests provide guidelines for assessing comparisons between air and ground temperatures at periods appropriate for climate reconstructions. The sensitivity of comparisons between the average Northern Hemisphere gridded SAT record and subsurface temperature-depth profile as a function of forcing period is assessed. This analysis indicates that the Northern Hemisphere extratropical average SAT and reduced temperature-depth profile are in good agreement. By adding modest heat to the subsurface at intermediate periods some improvement in misfit can be made, but this extra heat has negligible influence on the POM. The joint analysis of borehole temperatures and SAT records indicate warming of about 1.1 • C over the last 500 years, consistent with previous studies.

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“…During the winter, the air cools down more rapidly than the ground does (∆T > 0). The offset values predominantly depend on the local climate of the observation site [8].…”

Section: Datamentioning

confidence: 99%

“…Mann et al [12] showed that the air temperature has a dominant influence on the ground temperature during warm seasons. Smerdon et al [8] concluded that the connection between SAT and SGT at interannual time scales is stable and appears closer during the summer than during the winter. Thus, the SGT represents a confident proxy for annual surface air temperatures.…”

Section: One Harmonics Thermal Orbitsmentioning

confidence: 99%

Air-Ground Temperature Coupling: Analysis by Means of Thermal Orbits

Čermák¹,

Bodri²

2016

ACS

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Long-term measurements of air, near-surface (soil) and ground temperatures that were collected between 1994 and 2013 at the drill site of the Geothermal Climate Change Observatory (Prague) were analyzed to understand the relationship between these variables and to reveal the mechanisms of heat transport at the land-atmosphere boundary layer. The 2D Thermal Orbit (TO) method was applied to detect regularities that were hidden in noisy and highly variable temperature time series. The results showed that the temperatures at shallow depths were affected by surface air temperature (SAT) variations on seasonal and annual time scales and could be regarded as an accurate proxy for low frequency temperature variations at the Earth's surface. Only low-frequency/ high-amplitude surface temperature variations penetrate into the subsurface because of strong damping and the filtering effect of the ground surface. The borehole temperatures have good potential to capture temperature variations (periodicities) over long time scales that cannot be detected in the SAT series themselves because of the interference of higher frequency noise. The TO technique is a useful and powerful tool to quickly obtain diagnostics of the presence of long periodicities in borehole temperature time series.

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Air‐ground temperature coupling and subsurface propagation of annual temperature signals

Cited by 108 publications

References 59 publications

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

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

Variations in air and ground temperature and the POM-SAT model: results from the Northern Hemisphere

Air-Ground Temperature Coupling: Analysis by Means of Thermal Orbits

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