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| Titel |
Climate reconstruction fundamentals: Testing proxies for linearity. |
| VerfasserIn |
Bård Støve, Fredrik Charpentier Ljungqvist, Peter Thejll |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250050387
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| Zusammenfassung |
| Reconstructing past climate from so-called climate proxies is an important way to understand
climate variability. Fundamental properties of the climate system, such as the extent of
internal or natural variability and climate sensitivity can be established provided long and
accurate reconstructions are available. Many current climate reconstruction methods are
based on the assumption that a climate property - such as local or global-mean temperature -
is imprinted linearly on proxies, and reconstructors typically build linear models that relate
the proxies to the climate variable. The presence of such a linear relationship can be tested
using so-called non-parametric additive models, and we apply this tool for the first time
to a set of well-documented climate proxies relevant for the temperate northern
hemisphere. We find that most of the chosen proxies can indeed be shown to be linear
functions of the mean temperature, but one proxy - based on tree ring widths from the
Jämtland region of Sweden - does not appear to have a linear relationship with the
temperature. The method is quite general and could be used for larger and more
extensive sets of proxies - here we restrict the analysis to those proxies that have annual
resolution. |
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