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| Titel |
A few prospective ideas on climate reconstruction: from a statistical single proxy approach towards a multi-proxy and dynamical approach |
| VerfasserIn |
J. Guiot, H. B. Wu, V. Garreta, C. Hatté, M. Magny |
| 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 ; 5, no. 4 ; Nr. 5, no. 4 (2009-10-08), S.571-583 |
| Datensatznummer |
250002689
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| Publikation (Nr.) |
 copernicus.org/cp-5-571-2009.pdf |
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| Zusammenfassung |
| Important progresses have been made in palaeoclimatological studies by using
statistical methods. But they are in somewhere limited as they take the
present as an absolute reference. This is particularly true for the modern
analogue technique. The availability of mechanistic models to simulate the
proxies measured in the sediment cores gives now the possibility to relax
this constraint. In particular, vegetation models provide outputs comparable
to pollen data (assuming that there is a relationship between plant
productivity and pollen counts). The input of such models is, among others,
climate. The idea behind paleoclimatological reconstructions is then to
obtain inputs, given outputs. This procedure, called model inversion, can be
achieved with appropriate algorithms in the frame of the Bayesian statistical
theory. But we have chosen to present it in an intuitive way, avoiding the
mathematics behind it. Starting from a relative simple application, based on
an equilibrium BIOME3 model with a single proxy (pollen), the approach has
evolved into two directions: (1) by using several proxies measured on the
same core (e.g. lake-level status and δ13C) when they are related
to a component of the vegetation, and (2) by using a more complex vegetation
model, the dynamic vegetation model LPJ-GUESS. Examples presented (most of
them being already published) concern Last Glacial Maximum in Europe and
Africa, Holocene in a site of the Swiss Jura, an Eemian site in France. The
main results are that: (1) pollen alone is not able to provide exhaustive
information on precipitation, (2) assuming past CO2 equivalent to modern
one may induce biases in climate reconstruction, (3) vegetation models seem
to be too much constrained by temperature relative to precipitation in
temperate regions. This paper attempts to organise some recent ideas in the
palaeoclimatological reconstruction domain and to propose prospectives in
that effervescent domain. |
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