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Optimal Surface Temperature Reconstructions Using Terrestrial Borehole Data
Journal of Geophysical Research: Atmospheres (2003)
  • M. E Mann
  • S. Rutherford
  • Raymond S Bradley, University of Massachusetts - Amherst
  • M. K Hughes
  • F. T Keimig
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.
Publication Date
April, 2003
Publisher Statement
Doi:10.1029/2002JD002532 An edited version of this paper was published by AGU. Copyright 2003 American Geophysical Union.
Citation Information
M. E Mann, S. Rutherford, Raymond S Bradley, M. K Hughes, et al.. "Optimal Surface Temperature Reconstructions Using Terrestrial Borehole Data" Journal of Geophysical Research: Atmospheres Vol. 108 Iss. D7 (2003)
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