Proxy surrogate reconstructions for Europe and the estimation of their uncertainties
<p>Combining proxy information and climate model simulations reconciles these sources of information about past climates. This, in turn, strengthens our understanding of past climatic changes. The analogue or proxy surrogate reconstruction method is a computationally cheap data assimilation ap...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2020-02-01
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| Series: | Climate of the Past |
| Online Access: | https://www.clim-past.net/16/341/2020/cp-16-341-2020.pdf |
| Summary: | <p>Combining proxy information and climate model simulations reconciles
these sources of information about past climates. This, in turn,
strengthens our understanding of past climatic changes. The analogue or
proxy surrogate reconstruction method is a computationally cheap data
assimilation approach, which searches in a pool of simulated climate
states the best fit to proxy data. We use the approach to reconstruct
European summer mean temperature from the 13th century until present
using the Euro 2k set of proxy records and a pool of global climate
simulation output fields. Our focus is on quantifying the uncertainty of
the reconstruction, because previous applications of the analogue method
rarely provided uncertainty ranges. We show several ways of estimating
reconstruction uncertainty for the analogue method, which take into
account the non-climate part of the variability in each proxy record.</p>
<p>In general, our reconstruction agrees well at multi-decadal
timescales with the Euro 2k reconstruction, which was conducted with two
different statistical methods and no information from model simulations.
In both methodological approaches, the decades around the year 1600 CE were
the coldest. However, the approaches disagree on the warmest
pre-industrial periods. The reconstructions from the analogue method also
represent the local variations of the observed proxies.
The
diverse uncertainty estimates obtained from our analogue approaches can
be locally larger or smaller than the estimates from the Euro 2k effort.
Local uncertainties of the temperature reconstructions tend to be large
in areas that are poorly covered by the proxy records. Uncertainties
highlight the ambiguity of field-based reconstructions constrained by a
limited set of proxies.</p> |
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| ISSN: | 1814-9324 1814-9332 |