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Validity of the Temperature Reconstruction from Water Isotopes in Ice CoresWell-documented present-day distributions of stable water isotopes (HDO and others) show the existence, in middle and high latitudes, of a linear relationship between the mean annual isotope content of precipitation (SD and 51"0) and the mean annual temperature at the precipitation site. Paleoclimatologists have used this relationship, which is particularly well obeyed over Greenland and Antarctica, to infer paleotemperatures from ice core data. There is, however, growing evidence that spatial and temporal isotope/ surface temperature slopes differ, thus complicating the use of stable water isotopes as paleothermometers. In this paper we review empirical estimates of temporal slopes in polar regions and relevant information that can be inferred from isotope models: simple, Rayleigh-type distillation models and (particularly over Greenland) general circulation models (GCMS) fitted with isotope tracer diagnostics. Empirical estimates of temporal slopes appear consistently lower than present-day spatial slopes and are dependent on the timescale considered. This difference is most probably due to changes in the evaporative origins of moisture, changes in the seasonality of the precipitation, changes in the strength of the inversion layer, or some combination of these changes. Isotope models have not yet been used to evaluate the relative influences of these different factors. The apparent disagreement in the temporal and spatial slopes clearly makes calibrating the isotope paleothermometer difficult. Nevertheless, the use of a (calibrated) isotope paleothermometer appears justified; empirical estimates and most (though not all) GCM results support the practice of interpreting ice core isotope records in terms of local temperature changes.
Document ID
20000037967
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Jouzel, J.
(Centre National de la Recherche Scientifique Gif-sur-Yvette, France)
Alley, R. B.
(Pennsylvania State Univ. University Park, PA United States)
Cuffey, K. M.
(Washington Univ. Seattle, WA United States)
Dansgaard, W.
(Copenhagen Univ. Denmark)
Grootes, P.
(Washington Univ. Seattle, WA United States)
Hoffmann, G.
(Max-Planck-Inst. fuer Meteorologie Hamburg, Germany)
Johnsen, S. J.
(Copenhagen Univ. Denmark)
Koster, R. D.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Peel, D.
(British Antarctic Survey Cambridge, United Kingdom)
Shuman, C. A.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Stievenard, M.
(Centre National de la Recherche Scientifique Gif-sur-Yvette, France)
Stuiver, M.
(Washington Univ. Seattle, WA United States)
White, J.
(Colorado Univ. Boulder, CO United States)
Date Acquired
August 19, 2013
Publication Date
January 1, 1997
Publication Information
Publication: Laboratory for Hydrospheric Processes Research Publications
Subject Category
Oceanography
Distribution Limits
Public
Copyright
Other

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