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| Titel |
Impact of maximum borehole depths on inverted temperature histories in borehole paleoclimatology |
| VerfasserIn |
H. Beltrami, J. E. Smerdon, G. S. Matharoo, N. Nickerson |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1814-9324
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| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 7, no. 3 ; Nr. 7, no. 3 (2011-07-18), S.745-756 |
| Datensatznummer |
250004608
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| Publikation (Nr.) |
 copernicus.org/cp-7-745-2011.pdf |
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| Zusammenfassung |
| A quantitative assessment is presented for the impact of the maximum depth of
a temperature-depth profile on the estimate of the climatic transient and the
resultant ground surface temperature (GST) reconstruction used in borehole
paleoclimatology. The depth of the profile is important because the
downwelling climatic signal must be separated from the quasi-steady state
thermal regime established by the energy in the Earth's interior. This
component of the signal is estimated as a linear increase in temperature with
depth from the lower section of a borehole temperature profile, which is
assumed to be unperturbed by recent changes in climate at the surface. The
validity of this assumption is dependent on both the subsurface
thermophysical properties and the character of the downwelling climatic
signal. Such uncertainties can significantly impact the determination of the
quasi-steady state thermal regime, and consequently the magnitude of the
temperature anomaly interpreted as a climatic signal. The quantitative
effects and uncertainties that arise from the analysis of temperature-depth
profiles of different depths are presented. Results demonstrate that widely
different GST histories can be derived from a single temperature profile
truncated at different depths. Borehole temperature measurements approaching
500–600 m depths are shown to provide the most robust GST reconstructions
spanning 500 to 1000 yr BP. It is further shown that the bias introduced by a
temperature profile of depths shallower than 500–600 m remains even if the
time span of the reconstruction target is shortened. |
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