Research project CG/DD1/11 (Research action CG)
Context
Due to fossil fuel burning and land use change, the atmospheric carbon dioxide concentration has globally increased since 1800 from a preindustrial value of 280 ppm (part per million). Nevertheless, according the present value (around 360 ppm), only a fraction of the carbon released by the industrial activity remained in the atmosphere. The continental biosphere and the ocean take together about half of the annual release of industrial carbon. The ocean sink is explained by the ocean carbon cycle, which includes several chemical species and a biospheric component. Recent estimates (IPCC, 1995) ascribe a continental biospheric sink of carbon (0.5 to 2 gigatons/year) to vegetation fertilisation by atmospheric CO2.
Objectives
Our main purpose is to use a tri-dimensional model to quantify the past and future pert in the global carbon cycle. This model has to calculate the exchange fluxes of carbon between the ocean, the biosphere and the atmosphere. We intend to validate the model with respect to measurements of the oceanic chemical composition and satellite observations of the continental vegetation. The objectives of the programme are :
- To reconstruct the evolution of the biomass and the ecosystems in the last glacial maximum
- Starting from the pre-industrial steady state of the ocean and the biosphere, to determine their present carbon contents
- To deduce the future atmospheric CO2 concentration from forecasting simulations of the carbon exchanges between ocean, biosphere and atmosphere in the next century
This objective implies:
- Understanding the coastal processes and the quantification of their impact on the air-sea CO2 exchange;
- The introduction of the ocean margin in the ocean carbon cycle;
- A suitable description of the ocean biomass response to the spatial and seasonal change in nutrient availability;
- The definition of a methodology to deduce vegetation indices from remote sensing observations.
Partners
1. Prof. J.-C. GERARD, Dr. L. FRANCOIS, Laboratoire de Physique Atmosphérique et Planétaire:modeling of the global carbon cycle:
- Validation of the biospheric model with paleo-vegetation measurements, analysis of the climatic role in the carbon fluxes ;
- Oceanic module: improvement of the 3-D model, validation with measurements of the past , contribution of the ocean to the global budget of CO2 fluxes, coupling of the two components and scenarios for the future .
2. Pr. R. WOLLAST, Laboratoire d’Océanographie Chimique : development of a coupled hydrodynamical and biological to describe the fluxes of carbon and nutrients in ocean margins.
3. Dr. F. VEROUSTRAETE, Ir. H. Eerens, Centrum voor Teledetectie en Atmosferische Processen (TAP):
- Definition of a methodology to deduce vegetation indices from remote sensing observations from the NOAA and VEGATATION platforms;
- Application of this methodoly to validate the global biosphere model with respect to the observed vegetation indices (geolocalization of vegetation cover types);
Deliverables and expected results
- Assessment of the vegetation contribution to the past, present and future sinks of atmospheric CO2;
- Assessment of the ocean margin contribution to the present and future global carbon cycle;
- Identification and extraction of the vegetation biomes from the global satellite EROS-USGS datasets; these biomes will be used as input in the coupled hydrodynamical-biological model ;
- coupling ocean, biosphere and atmosphere models into a three-dimensional model of the global carbon cycle; application to the past, present and future levels of atmospheric CO2;
Scientific collaboration
- Participation in the international IGBP program of modeled NPP intercomparison: analysis of the seasonal atmospheric CO2;
- Participation in the international OCMIP program of modeled ocean carbon cycle intercomparison;
- Coordination of the European OMEX program devoted to the estimate of carbon fluxes in the European ocean margin;
- Participation in the European BIOGEST program on estimates of greenhouse gas fluxes in the estuaries;
- Participation in the preliminary program of the VEGETATION sensor toward the composition of multitemporal NDVI pictures;
