Ground surface temperature and continental heat gain: uncertainties from underground
Temperature changes at the Earthʼs surface propagate and are recorded underground as perturbations to the equilibrium thermal regime associated with the heat flow from the Earthʼs interior. Borehole climatology is concerned with the analysis and interpretation of these downward propagating subsurfac...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2015-01-01
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| Series: | Environmental Research Letters |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/1748-9326/10/1/014009 |
| _version_ | 1797748835676585984 |
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| author | Hugo Beltrami Gurpreet S Matharoo Jason E Smerdon |
| author_facet | Hugo Beltrami Gurpreet S Matharoo Jason E Smerdon |
| author_sort | Hugo Beltrami |
| collection | DOAJ |
| description | Temperature changes at the Earthʼs surface propagate and are recorded underground as perturbations to the equilibrium thermal regime associated with the heat flow from the Earthʼs interior. Borehole climatology is concerned with the analysis and interpretation of these downward propagating subsurface temperature anomalies in terms of surface climate. Proper determination of the steady-state geothermal regime is therefore crucial because it is the reference against which climate-induced subsurface temperature anomalies are estimated. Here, we examine the effects of data noise on the determination of the steady-state geothermal regime of the subsurface and the subsequent impact on estimates of ground surface temperature (GST) history and heat gain. We carry out a series of Monte Carlo experiments using 1000 Gaussian noise realizations and depth sections of 100 and 200 m as for steady-state estimates depth intervals, as well as a range of data sampling intervals from 10 m to 0.02 m. Results indicate that typical uncertainties for 50 year averages are on the order of ±0.02 K for the most recent 100 year period. These uncertainties grow with decreasing sampling intervals, reaching about ±0.1 K for a 10 m sampling interval under identical conditions and target period. Uncertainties increase for progressively older periods, reaching ±0.3 K at 500 years before present for a 10 m sampling interval. The uncertainties in reconstructed GST histories for the Northern Hemisphere for the most recent 50 year period can reach a maximum of $\pm 0.5\;{\rm K}$ in some areas. We suggest that continuous logging should be the preferred approach when measuring geothermal data for climate reconstructions, and that for those using the International Heat Flow Commission database for borehole climatology, the steady-state thermal conditions should be estimated from boreholes as deep as possible and using a large fitting depth range (∼100 m). |
| first_indexed | 2024-03-12T16:10:34Z |
| format | Article |
| id | doaj.art-86bb0ffda0c148d5b1430886d7809b31 |
| institution | Directory Open Access Journal |
| issn | 1748-9326 |
| language | English |
| last_indexed | 2024-03-12T16:10:34Z |
| publishDate | 2015-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | Environmental Research Letters |
| spelling | doaj.art-86bb0ffda0c148d5b1430886d7809b312023-08-09T14:08:59ZengIOP PublishingEnvironmental Research Letters1748-93262015-01-0110101400910.1088/1748-9326/10/1/014009Ground surface temperature and continental heat gain: uncertainties from undergroundHugo Beltrami0Gurpreet S Matharoo1Jason E Smerdon2Climate & Atmospheric Sciences Institute and Department of Earth Sciences, St. Francis Xavier University , Antigonish, Nova Scotia, Canada; Centre pour l’étude et la simulation du climat à l’échelle régionale (ESCER), Université du Québec à Montréal , Montréal, Québec, CanadaClimate & Atmospheric Sciences Institute and Department of Earth Sciences, St. Francis Xavier University , Antigonish, Nova Scotia, CanadaLamont-Doherty Earth Observatory, Columbia University , Palisades, New York, USATemperature changes at the Earthʼs surface propagate and are recorded underground as perturbations to the equilibrium thermal regime associated with the heat flow from the Earthʼs interior. Borehole climatology is concerned with the analysis and interpretation of these downward propagating subsurface temperature anomalies in terms of surface climate. Proper determination of the steady-state geothermal regime is therefore crucial because it is the reference against which climate-induced subsurface temperature anomalies are estimated. Here, we examine the effects of data noise on the determination of the steady-state geothermal regime of the subsurface and the subsequent impact on estimates of ground surface temperature (GST) history and heat gain. We carry out a series of Monte Carlo experiments using 1000 Gaussian noise realizations and depth sections of 100 and 200 m as for steady-state estimates depth intervals, as well as a range of data sampling intervals from 10 m to 0.02 m. Results indicate that typical uncertainties for 50 year averages are on the order of ±0.02 K for the most recent 100 year period. These uncertainties grow with decreasing sampling intervals, reaching about ±0.1 K for a 10 m sampling interval under identical conditions and target period. Uncertainties increase for progressively older periods, reaching ±0.3 K at 500 years before present for a 10 m sampling interval. The uncertainties in reconstructed GST histories for the Northern Hemisphere for the most recent 50 year period can reach a maximum of $\pm 0.5\;{\rm K}$ in some areas. We suggest that continuous logging should be the preferred approach when measuring geothermal data for climate reconstructions, and that for those using the International Heat Flow Commission database for borehole climatology, the steady-state thermal conditions should be estimated from boreholes as deep as possible and using a large fitting depth range (∼100 m).https://doi.org/10.1088/1748-9326/10/1/014009borehole temperaturespaleoclimatecontinental heatclimate changeuncertainties |
| spellingShingle | Hugo Beltrami Gurpreet S Matharoo Jason E Smerdon Ground surface temperature and continental heat gain: uncertainties from underground Environmental Research Letters borehole temperatures paleoclimate continental heat climate change uncertainties |
| title | Ground surface temperature and continental heat gain: uncertainties from underground |
| title_full | Ground surface temperature and continental heat gain: uncertainties from underground |
| title_fullStr | Ground surface temperature and continental heat gain: uncertainties from underground |
| title_full_unstemmed | Ground surface temperature and continental heat gain: uncertainties from underground |
| title_short | Ground surface temperature and continental heat gain: uncertainties from underground |
| title_sort | ground surface temperature and continental heat gain uncertainties from underground |
| topic | borehole temperatures paleoclimate continental heat climate change uncertainties |
| url | https://doi.org/10.1088/1748-9326/10/1/014009 |
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