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| Titel |
A method for estimating the age–depth relationship of Dome Fuji Ice Core using a sequential Monte Carlo method |
| VerfasserIn |
Shinya Nakano, Kazue Suzuki, Kenji Kawamura, Frédéric Parrenin, Tomoyuki Higuchi |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250108493
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| Publikation (Nr.) |
 EGU/EGU2015-8249.pdf |
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| Zusammenfassung |
| A technique for estimating the age–depth relationship and its uncertainty in ice cores has
been developed. The age–depth relationship is mainly determined by the accumulation of
snow at the site of the ice core and the thinning process due to the horizontal stretching and
vertical compression of an ice layer. However, both the accumulation process and the
thinning process are not fully known. In order to appropriately estimate the age as a function
of depth, it is crucial to incorporate observational information into a model describing
the accumulation and thinning processes. In the proposed technique, the age as
a function of depth is estimated from age markers and time series of δ18O data.
The estimation is achieved using a method combining a sequential Monte Carlo
method and the Markov chain Monte Carlo method as proposed by Andrieu et
al. (2010). In this hybrid method, the posterior distributions for the parameters in
the models for the accumulation and thinning processes are basically computed
using a way of the standard Metropolis-Hastings method. Meanwhile, sampling
from the posterior distribution for the age–depth relationship is achieved by using
a sequential Monte Carlo approach at each iteration of the Metropolis-Hastings
method. A sequential Monte Carlo method normally suffers from the degeneracy
problem, especially in cases that the number of steps is large. However, when it is
combined with the Metropolis-Hastings method, the degeneracy problem can be
overcome by collecting a large number of samples obtained by many iterations
of the Metropolis-Hastings method. We will demonstrate the result obtained by
applying the proposed technique to the ice core data from Dome Fuji in Antarctica. |
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