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Amelioration et validation du modele de fonctionnement de la végétation ISBA-A-gs: stress hydrique et flux de CO2

Abstract : Land surfaces schemes were developed with the aim of modelling the water and heat transfers between continental surfaces and the atmosphere. Among the components of these surfaces, the vegetation plays an important part in the dynamic of fluxes at the interface. My thesis work concerned the parameterization improvement of the surface vegetation model: ISBA-A-gs (Calvet et al, 1998). Besides solving the surface energy and water budget, this model is able to evaluate the green biomass increment of the vegetation and to estimate the leaf surface according to the climate evolution, particularly the increase of CO2 atmospheric concentration. My contribution concerned the development and the application of a water stress parameterization related to the physiological functioning of woody vegetation. I used a methodology consisting in a meta-analysis of the literature information. This methods had already been used by Calvet (2000) for herbaceous species. An application and validation work was undertaken for 3 continuous data sets from 3 European forest sites of the EUROFLUX / CarboEurope network. These data included the traditional energy budget combined with a continuous CO2 fluxes measurements. Thus and for the first time, it was possible to test the model capacity to simulate the diurnal cycle of the CO2 fluxes as well as the net annual carbon storage (Rivalland and al., 2005). Finally, I could evaluate the potentialities of a new version of the model developed by Calvet and Soussana (2001), taking into account the effect of CO2 atmospheric enrichment on the vegetation growth, associated with the soil nitrogen fertility. This model version separates the various storage compartments of the vegetation and opens prospects in modelling the complete carbon cycle and the climatic change effects on the vegetation. Along with this work, a meta-analysis and a ground experiment of nitrogen enrichment was carried out in order to determine the plasticity parameters associated with various cover types. An evaluation of the model simulations on a wheat crop was carried out by comparing the model with the INRA generic crop model STICS.
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https://tel.archives-ouvertes.fr/tel-00009717
Contributor : Vincent Rivalland <>
Submitted on : Saturday, July 9, 2005 - 1:02:28 PM
Last modification on : Friday, April 5, 2019 - 8:14:09 PM
Long-term archiving on: : Friday, September 14, 2012 - 1:40:22 PM

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  • HAL Id : tel-00009717, version 1

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Vincent Rivalland. Amelioration et validation du modele de fonctionnement de la végétation ISBA-A-gs: stress hydrique et flux de CO2. Physique [physics]. Université Paul Sabatier - Toulouse III, 2003. Français. ⟨tel-00009717⟩

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