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| Titel |
Estimation of sedimentary proxy records together with associated uncertainty |
| VerfasserIn |
B. Goswami, J. Heitzig, K. Rehfeld, N. Marwan, A. Anoop, S. Prasad, J. Kurths |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1023-5809
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| Digitales Dokument |
URL |
| Erschienen |
In: Nonlinear Processes in Geophysics ; 21, no. 6 ; Nr. 21, no. 6 (2014-11-11), S.1093-1111 |
| Datensatznummer |
250120951
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| Publikation (Nr.) |
 copernicus.org/npg-21-1093-2014.pdf |
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| Zusammenfassung |
Sedimentary proxy records constitute a significant portion of the recorded
evidence that allows us to investigate paleoclimatic conditions and
variability. However, uncertainties in the dating of proxy archives limit our
ability to fix the timing of past events and interpret proxy record
intercomparisons. While there are various age-modeling approaches to improve
the estimation of the age–depth relations of archives, relatively little
focus has been placed on the propagation of the age (and radiocarbon
calibration) uncertainties into the final proxy record.
We present a generic Bayesian framework to estimate proxy records along with
their associated uncertainty, starting with the radiometric age–depth and
proxy–depth measurements, and a radiometric calibration curve if required.
We provide analytical expressions for the posterior proxy probability
distributions at any given calendar age, from which the expected proxy values
and their uncertainty can be estimated. We illustrate our method using two
synthetic data sets and then use it to construct the proxy records for
groundwater inflow and surface erosion from Lonar lake in central India.
Our analysis reveals interrelations between the uncertainty of the proxy
record over time and the variance of proxies along the depth of the archive.
For the Lonar lake proxies, we show that, rather than the age uncertainties,
it is the proxy variance combined with calibration uncertainty that accounts
for most of the final uncertainty. We represent the proxy records as
probability distributions on a precise, error-free timescale that makes
further time series analyses and intercomparisons of proxies relatively
simple and clear. Our approach provides a coherent understanding of age
uncertainties within sedimentary proxy records that involve radiometric
dating. It can be potentially used within existing age modeling structures to
bring forth a reliable and consistent framework for proxy record estimation. |
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