In:
Ecologia mediterranea, PERSEE Program, Vol. 25, No. 2 ( 1999), p. 193-204
Abstract:
Classical climate reconstruction based on statistical method implicitly assumes that the atmospheric C02 concentration, which has greatly fluctuated during the Quaternary, has no influence on the vegetation. In order to attenuate this assumption, we propose to use a process-based vegetation model (BIOME 3.5) in inverse mode to reconstruct from pollen data the most probable climate under lowered C02 concentration in the biosphere. Appropriate tools to match the model outputs with the pollen data are developed to generate a probability distribution associated with the reconstruction (Monte Carlo sampling and neural network techniques). The method is validated with modern pollen data from Europe and Northern Eurasia : it is able to reconstruct modern climate with a sometimes large error bar from pollen data. The error bar depends in fact on the tolerance of the vegetation to the corresponding climatic variable. The application to 7 1 pollen assemblages from these regions, representing the last glacial maximum (LGM : 18,000 14C-yr B.P.), is done through two experiments : modem and LGM C02 concentration. We show that there is a good agreement between previous results based on statistical methods and inverse modelling in the northern part of the studied region. In the Mediterranean region and southern Siberia, the summer temperatures and the water availability parameters could be higher than previously reconstructed, because of the C02 effect.
Type of Medium:
Online Resource
ISSN:
0153-8756
DOI:
10.3406/ecmed.1999.1884
Language:
French
Publisher:
PERSEE Program
Publication Date:
1999
SSG:
12
Permalink
