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| Titel |
Inter-annual tropical Pacific climate variability in an isotope-enabled CGCM: implications for interpreting coral stable oxygen isotope records of ENSO |
| VerfasserIn |
T. Russon, A. W. Tudhope, G. C. Hegerl, M. Collins, J. Tindall |
| 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 ; 9, no. 4 ; Nr. 9, no. 4 (2013-07-22), S.1543-1557 |
| Datensatznummer |
250018091
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| Publikation (Nr.) |
 copernicus.org/cp-9-1543-2013.pdf |
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| Zusammenfassung |
| Water isotope-enabled coupled atmosphere–ocean climate models allow for
exploration of the relative contributions to coral stable oxygen isotope
(δ18Ocoral) variability arising from sea surface
temperature (SST) and the isotopic composition of seawater
(δ18Osw). The unforced behaviour of the isotope-enabled
HadCM3 coupled general circulation model suggests that the extent to which
inter-annual δ18Osw variability contributes to that in
model δ18Ocoral is strongly spatially dependent,
ranging from being negligible in the eastern equatorial Pacific to accounting
for 50% of δ18Ocoral variance in parts of the
western Pacific. In these latter cases, a significant component of the
inter-annual δ18Osw variability is correlated to that
in SST, meaning that local calibrations of the effective local
δ18Ocoral–SST relationships are likely to be
essential. Furthermore, the relationship between δ18Osw
and SST can be non-linear, such that the model interpretation of central and
western equatorial Pacific δ18Ocoral in the context of
a linear dependence on SST alone leads to overestimation (by up to 20%)
of the SST anomalies associated with large El Niño events. Intra-model
evaluation of a salinity-based pseudo-coral approach shows that such an
approach captures the first-order features of the model
δ18Osw behaviour. However, the utility of the
pseudo-corals is limited by the extent of spatial variability seen within the
modelled slopes of the temporal salinity–δ18Osw
relationship. |
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