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| Titel |
An introduction to stable water isotopes in climate models: benefits of forward proxy modelling for paleoclimatology |
| VerfasserIn |
C. Sturm, Q. Zhang, D. Noone |
| 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 ; 6, no. 1 ; Nr. 6, no. 1 (2010-02-26), S.115-129 |
| Datensatznummer |
250003330
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| Publikation (Nr.) |
 copernicus.org/cp-6-115-2010.pdf |
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| Zusammenfassung |
| Stable water isotopes have been measured in a wide range of climate
archives, with the purpose of reconstructing regional climate
variations. Yet the common assumption that the isotopic signal is a
direct indicator of temperature proves to be misleading under
certain circumstances, since its relationship with temperature also
depends on e.g. atmospheric circulation and precipitation
seasonality. Here we introduce the principles, benefits and caveats
of using climate models with embedded water isotopes as a support
for the interpretation of isotopic climate archives. A short
overview of the limitations of empirical calibrations of isotopic
proxy records is presented. In some cases, the underlying hypotheses
are not fulfilled and the calibration contradicts the physical
interpretation of isotopic fractionation. The simulation of climate
and its associated isotopic signal, despite difficulties related to
downscaling and intrinsic atmospheric variability, can provide a
"transfer function" between the isotopic signal and the considered
climate variable. The relationship between modelled temperature and
isotopic signal is analysed under present-day, pre-industrial and
mid-Holocene conditions. The linear regression relationship is
statistically more significant for precipitation-weighted annual
temperature than mean annual temperature, yet the regression slope
varies greatly between the time-slice experiments. Temperature
reconstructions that do not account for the slope variations will in
this case underestimate the low-frequency variability and
overestimate high-frequency variability from the isotopic proxy
record. The spatial variability of the simulated δ18O-temperature
slope further indicates that the isotopic signal is primarily
controlled by synoptic atmospheric circulation rather than local
temperature. |
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