Quantifying errors in coral-based ENSO estimates: Toward improved forward modeling of delta O-18 Stevenson, S. en_US McGregor, H.V. en_US Phipps, Steven en_US Fox-Kemper, B. en_US 2021-11-25T12:29:03Z 2021-11-25T12:29:03Z 2013 en_US
dc.description.abstract The oxygen isotopic ratio (O-18) in tropical Pacific coral skeletons reflects past El Nino-Southern Oscillation (ENSO) variability, but the O-18-ENSO relationship is poorly quantified. Uncertainties arise when constructing O-18 data sets, combining records from different sites, and converting between O-18 and sea surface temperature (SST) and salinity (SSS). Here we use seasonally resolved O-18 from 1958 to 1985 at 15 tropical Pacific sites to estimate these errors and evaluate possible improvements. Observational uncertainties from Kiritimati, New Caledonia, and Rarotonga are 0.12-0.14, leading to errors of 8-25% on the typical O-18 variance. Multicoral syntheses using five to seven sites capture the principal components (PCs) well, but site selection dramatically influences ENSO spatial structure: Using sites in the eastern Pacific, western Pacific warm pool, and South Pacific Convergence Zone (SPCZ) captures eastern Pacific-type variability, while Central Pacific-type events are best observed by combining sites in the warm pool and SPCZ. The major obstacle to quantitative ENSO estimation is the O-18/climate conversion, demonstrated by the large errors on both O-18 variance and the amplitude of the first principal component resulting from the use of commonly employed bivariate formulae to relate SST and SSS to O-18. Errors likely arise from either the instrumental data used for pseudoproxy calibration or influences from other processes (O-18 advection/atmospheric fractionation, etc.). At some sites, modeling seasonal changes to these influences reduces conversion errors by up to 20%. This indicates that understanding of past ENSO dynamics using coral O-18 could be greatly advanced by improving O-18 forward models. en_US
dc.identifier.issn 1944-9186 en_US
dc.language English
dc.language.iso EN en_US
dc.rights CC BY-NC-ND 3.0 en_US
dc.rights.uri en_US
dc.source Legacy MARC en_US
dc.title Quantifying errors in coral-based ENSO estimates: Toward improved forward modeling of delta O-18 en_US
dc.type Journal Article en
dcterms.accessRights open access
dspace.entity.type Publication en_US
unsw.description.publisherStatement Copyright American Geophysical Union 2013. Published version available at en_US
unsw.identifier.doiPublisher en_US
unsw.relation.faculty Science
unsw.relation.ispartofjournal Paleoceanography en_US
unsw.relation.ispartofpagefrompageto 633-649 en_US
unsw.relation.ispartofvolume 28 en_US
unsw.relation.originalPublicationAffiliation Stevenson, S. en_US
unsw.relation.originalPublicationAffiliation McGregor, H.V. en_US
unsw.relation.originalPublicationAffiliation Phipps, Steven, Climate Change Research Centre (CCRC), Faculty of Science, UNSW en_US
unsw.relation.originalPublicationAffiliation Fox-Kemper, B. en_US School of Biological, Earth & Environmental Sciences *
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