Atmos. Chem. Phys. Discuss., 12, 24131-24172, 2012
www.atmos-chem-phys-discuss.net/12/24131/2012/
doi:10.5194/acpd-12-24131-2012
© Author(s) 2012. This work is distributed
under the Creative Commons Attribution 3.0 License.
Review Status
This discussion paper has been under review for the journal Atmospheric Chemistry and Physics (ACP). Please refer to the corresponding final paper in ACP.
Quantifying the constraint of biospheric process parameters by CO2 concentration and flux measurement networks through a carbon cycle data assimilation system
E. Koffi1, P. Rayner2, M. Scholze3, F. Chevallier1, and T. Kaminski4
1Laboratoire des Sciences du Climat et de l'Environnement (LSCE), UMR8212, Ormes des merisiers, 91191 Gif-sur-Yvette, France
2School of Earth Sciences, University of Melbourne, Australia
3School of Earth Sciences, University of Bristol, Queen's Road, Bristol BS8 1RJ, UK
4FastOpt, Hamburg, Germany

Abstract. The sensitivity of the process parameters of the biosphere model BETHY (Biosphere Energy Transfer HYdrology) to choices of atmospheric concentration network, high frequency terrestrial fluxes, and the choice of flux measurement network is investigated by using a carbon cycle data assimilation system. Results show that monthly mean or low-frequency observations of CO2 concentration provide strong constraints on parameters relevant for net flux (NEP) but only weak constraints for parameters controlling gross fluxes. The use of high-frequency CO2 concentration observations, which has allowed a great refinement of spatial scales in direct inversions, adds little to the observing system in this case. This unexpected result is explained by the fact that the stations of the CO2 concentration network we are using are not well placed to measure such high frequency signals. Indeed, CO2 concentration sensitivities relevant for such high frequency fluxes are found to be largely confined in the vicinity of the corresponding fluxes, and are therefore not well observed by background monitoring stations. In contrast, our results clearly show the potential of flux measurements to better constrain the model parameters relevant for gross primary productivity (GPP) and net primary productivity (NPP). Given uncertainties in the spatial description of ecosystem functions we recommend a combined observing strategy.

Citation: Koffi, E., Rayner, P., Scholze, M., Chevallier, F., and Kaminski, T.: Quantifying the constraint of biospheric process parameters by CO2 concentration and flux measurement networks through a carbon cycle data assimilation system, Atmos. Chem. Phys. Discuss., 12, 24131-24172, doi:10.5194/acpd-12-24131-2012, 2012.
 
Search ACPD
Discussion Paper
    XML
    Citation
    Final Revised Paper
    Share