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display opposite long-term trends, with progressing drier conditions in ECHAM5
+CCLM and wetter conditions in ECHO-G+MM5. In areas with less complex ter-
rain (Central Europe), the difference between the regional models is less pronounced
(cf. Fig.
1
b). In these areas the usage of the direct GCM output
—
without further
dynamical downscaling
appears a reasonable option.
Results of the PPE show in general high correlations in areas close to the proxy
data for both methods. However, the complexity of precipitation complicates its
(spatial) reconstruction, re
—
ected by the lack of correlations in areas far away from
proxy locations (i.e., the decrease of correlations with increase in distance from the
proxy location in Fig.
2
).
It is worth to be mentioned that this is an idealized experiment, where the
pseudoproxies contain perfect information. Therefore these results should be
viewed as the theoretically optimal result that can be achieved when applying the
methods unchanged to real proxies. Despite its underlying simple assumptions the
BHM using the BARCAST algorithm performs as well as the analog method.
Future work will concentrate on establishing potential relationships between the
evolution of precipitation and changes in external forcings and internal variability.
In this context, precipitation variability, also on longer time scales, is far more
complex and spatially more heterogeneous and links with changes in external
forcings are most likely to be weaker compared to temperatures. Moreover the
methods used for the PPEs will be applied to real proxies related to the hydrological
cycle including tree rings, varved lake sediments and speleothems. As indicated in
the results correlations between temperature and precipitation in terms of warmer/
drier and colder/wetter summers could be identi
uenced
cultures and societies in pre-industrial Europe in the last 2,000 years (i.e., Tol and
Wagner
2010
).
ed that might have also in
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