%0 Journal Article
%T Inter-annual tropical Pacific climate variability in an isotope-enabled CGCM: implications for interpreting coral stable oxygen isotope records of ENSO
%A T. Russon
%A A. W. Tudhope
%A G. C. Hegerl
%A M. Collins
%J Climate of the Past Discussions
%D 2013
%I Copernicus Publications
%R 10.5194/cpd-9-741-2013
%X Water isotope-enabled coupled atmosphere/ocean climate models allow for exploration of the relative contributions to coral stable oxygen isotope (¦Ä18Ocoral) variability arising from Sea Surface Temperature (SST) and the isotopic composition of seawater (¦Ä18Osw). The unforced behaviour of the isotope-enabled HadCM3 Coupled General Circulation Model affirms that the extent to which inter-annual ¦Ä18Osw variability contributes to that in model ¦Ä18Ocoral is strongly spatially dependent, ranging from being negligible in the eastern equatorial Pacific to accounting for 50% of ¦Ä18Ocoral variance in parts of the western Pacific. In these latter cases, a significant component of the inter-annual ¦Ä18Osw variability is correlated to that in SST, meaning that local calibrations of the effective local ¦Ä18Ocoral¨CSST relationships are likely to be essential. Furthermore, the relationship between ¦Ä18Osw and SST in the central and western equatorial Pacific is non-linear, such that the interpretation of model ¦Ä18Ocoral in the context of a linear dependence on SST alone may lead to overestimation (by up to 20%) of the SST anomalies associated with large El-Ni o events. Intra-model evaluation of a salinity-based pseudo-coral approach shows that such an approach captures the first-order features of the model ¦Ä18Osw 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¨C¦Ä18Osw relationship.
%U http://www.clim-past-discuss.net/9/741/2013/cpd-9-741-2013.pdf