Optimal surface temperature reconstructions using terrestrial borehole data
| Autor: | Raymond S. Bradley, Scott Rutherford, Frank T. Keimig, Michael E. Mann, Malcolm K. Hughes |
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| Rok vydání: | 2003 |
| Předmět: |
Atmospheric Science
Ecology Optimal estimation Meteorology Noise (signal processing) Northern Hemisphere Borehole Paleontology Soil Science Forestry Aquatic Science Oceanography Geodesy Atmospheric temperature Geophysics Space and Planetary Science Geochemistry and Petrology Earth and Planetary Sciences (miscellaneous) Detection theory Geology Eigenvalues and eigenvectors Eigendecomposition of a matrix Earth-Surface Processes Water Science and Technology |
| Zdroj: | Journal of Geophysical Research. 108 |
| ISSN: | 0148-0227 |
| DOI: | 10.1029/2002jd002532 |
| Popis: | [1] We derive an optimal Northern Hemisphere mean surface temperature reconstruction from terrestrial borehole temperature profiles spanning the past five centuries. The pattern of borehole ground surface temperature (GST) reconstructions displays prominent discrepancies with instrumental surface air temperature (SAT) estimates during the 20th century, suggesting the presence of a considerable amount of noise and/or bias in any underlying spatial SAT signal. The vast majority of variance in the borehole dataset is efficiently retained by its two leading eigenvectors. A sizable share of the variance in the first eigenvector appears to be associated with non-SAT related bias in the borehole data. A weak but detectable SAT signal appears to be described by a combination of the first two eigenvectors. Exploiting this eigendecomposition, application of optimal signal estimation methods yields a hemispheric borehole SAT reconstruction that is largely consistent with instrumental data available in past centuries, and is indistinguishable in its major features from several published long-term temperature estimates based on both climate proxy data and model simulations. |
| Databáze: | OpenAIRE |
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