To reconstruct European climate from continental pollen sequences
at selected climatic episodes during the last two climatic
cycles, to validate GCM simulations of climate and derived
distribution of biomes for these climatic episodes, and to
evaluate impacts on climate of vegetation changes.
The largest available amount of pollen, insects, and lake-levels
proxy data pointing to the absence of those arboreal species that
are today not indigeneous in Europe, i.e. data subsequent to
about 250 Ka BP, will be collected mainly from Greece, Italy,
France, and the British Isles. They will enable the definition
of the spatial and temporal variability of the records of the best
characterized episodes, particularly changeover episodes.
The reconstructions of vegetations and corresponding climates
will be carried out thanks to an extension of the European Pollen
Database and to an enlargement of the bases of climate
reconstructions : they will consist, on the one hand, of the
comparison between results obtained by the nearest analogues
method and those derived from the technique of response surfaces,
and on the other hand, in the constraint of reconstructions from
pollen data by other proxy-data (insects, lake-levels).
The validation of GCM results will be made by comparing the
reconstructed vegetation and climate distributions derived either
directly from palaeodata or from the global biomes model forced
by the GCM outputs. In particular the simulated water-balance
and the biome maps based on GCM experiments for each time period
will be compared with the entirely independent reconstructions of lake
levels and vegetation for the corresponding period.
In order to obtain a fully realistic simulation of past (or
future) climate, the interaction of vegetation and climate will
be approached by coupling a process-based biome model (developed
at Lund) with the Laboratoire de Météorologie Dynamique GCMs.
This experiment will comprise three simulations : A simulation
of the present climate with the present vegetation introduced in
the inputs, a simulation of the climate of a past period with the
present vegetation, and a simulation of that same period but
with the introduction of the vegetation obtained using the biome model
based on the climatic results of the second simulation.
Comparisons and experiments will concern only two or three
changeover points that are particularly well documented as
regards palaeodata, principally the 6 kyr BP episode.
Call for proposalData not available
Funding SchemeCSC - Cost-sharing contracts
223 62 Lund
9712 ER Groningen
CB2 1TN Cambridge
DH1 3LE Durham