Canal-U

Comparison of Simulated Tree-Ring Cellulose d180 at the European Scale

In order to investigate factors involved in the inter-annual variability of d180 in tree ring cellulose (d18OTRC), we simulated the d18OTRC from 1960 to 2001 over Europe. We used 1) simulated climate and water isotope fields of REMOiso, a meso-scale circulation model, 2) hypotheses of the distribution of roots and soil hydrology, and 3) a mechanistic model of oxygen-isotopes in tree ring cellulose (d18OTRC). Sensitivity tests show that relative humidity of the air and soil water d18O contribute differently to the d180 in tree ring cellulose according to regional climate. In the commonly observed hydrological situation, humidity of the air may contribute to 70% to the d18OTRC at a given site, but only to 40 % at a warmer and drier site experiencing. We conclude that comparing time series of d180 in tree ring cellulose at the continental scale is questionable.