 |
| Titel |
Estimation of sedimentary proxy records together with associated uncertainty |
| VerfasserIn |
B. Goswami, J. Heitzig, K. Rehfeld, N. Marwan, A. Ambili, S. Prasad, J. Kurths |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
2198-5634
|
| Digitales Dokument |
URL |
| Erschienen |
In: Nonlinear Processes in Geophysics Discussions ; 1, no. 1 ; Nr. 1, no. 1 (2014-06-24), S.1023-1071 |
| Datensatznummer |
250115101
|
| Publikation (Nr.) |
 copernicus.org/npgd-1-1023-2014.pdf |
|
|
|
|
|
| Zusammenfassung |
Sedimentary proxy records constitute a significant portion of the
recorded evidence that allow 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 inter-comparisons. While there are various
age-modeling approaches to improve the estimation of the age-depth
relations of archives, relatively less focus has been given to 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 datasets 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 proxy 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 time scale that makes further time series analyses and
inter-comparison of proxies relatively simpler and clearer. 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. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|