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| Titel |
Technical Note: Probabilistically constraining proxy age–depth models within a Bayesian hierarchical reconstruction model |
| VerfasserIn |
J. P. Werner, M. P. Tingley |
| 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 ; 11, no. 3 ; Nr. 11, no. 3 (2015-03-24), S.533-545 |
| Datensatznummer |
250117214
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| Publikation (Nr.) |
 copernicus.org/cp-11-533-2015.pdf |
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| Zusammenfassung |
Reconstructions of the late-Holocene climate rely heavily upon proxies
that are assumed to be accurately dated by layer counting, such as
measurements of tree rings, ice cores, and varved lake sediments.
Considerable advances could be achieved if time-uncertain proxies
were able to be included within these multiproxy reconstructions, and if
time uncertainties were recognized and correctly modeled for proxies
commonly treated as free of age model errors.
Current approaches for accounting for time uncertainty are generally
limited to repeating the reconstruction using each one of an ensemble of
age models, thereby inflating the final estimated uncertainty – in
effect, each possible age model is given equal
weighting. Uncertainties can be reduced by exploiting the inferred
space–time covariance structure of the climate to re-weight the
possible age models. Here, we demonstrate how Bayesian hierarchical
climate reconstruction models can be augmented to account for time-uncertain proxies. Critically, although a priori all age models are
given equal probability of being correct, the probabilities
associated with the age models are formally updated within the
Bayesian framework, thereby reducing uncertainties. Numerical
experiments show that updating the age model probabilities decreases
uncertainty in the resulting reconstructions, as compared with the
current de facto standard of sampling over all age models, provided
there is sufficient information from other data sources in the
spatial region of the time-uncertain proxy. This approach can readily be
generalized to non-layer-counted proxies, such as those derived from
marine sediments. |
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