METHODOLOGY OF THE LAST CLIMATIC CYCLE RECONSTRUCTION IN FRANCE FROM POLLEN DATA

A numerical method has been devised to reconstruct the climate of the last climatic cycle from pollen data. Reliable annual reconstructions have been published recently for the two French long sequences of La Grande Pile and Les Echets covering the last 140 millennia. This paper gives more details on the method used. It proposes new reconstructions based on an extended modern pollen data base. These reconstructions are consistent with the previous ones. Especially, detailed information is obtained on the seasonal characteristics of climate. Computations of GCM on the climate variations from 125 kyr to 115 kyr B.P. are confirmed for Western Europe. The insolation variations have induced at that time a decrease of seasonality accompanied by an increased cyclonic activity in winter. This has been the beginning of the first ice growth after the Last Interglacial. Other glacier growth phases are detected at the end of Substage 5c and particularly at the end of Substage 5a. © 1990.