On the assignment of prior errors in Bayesian inversions of CO 2 surface fluxes

Frédéric Chevallier (1, 2) , Nicolas Viovy (1, 3) , Markus Reichstein (4) , Philippe Ciais (1, 5)

1 LSCE - Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette]
2 SATINV - Modélisation INVerse pour les mesures atmosphériques et SATellitaires
3 MOSAIC - Modélisation des Surfaces et Interfaces Continentales
4 MPI-BGC - Max Planck Institute for Biogeochemistry
5 ICOS-ATC - ICOS-ATC

[1] For the estimation of surface CO 2 fluxes from atmospheric concentration measurements, most often Bayesian approaches have been adopted. As with all Bayesian techniques the definition of prior probability distributions is a critical step in the analysis. However, practical considerations usually guide the definition of prior information rather than objective criterions. In this paper, in situ CO 2 flux pointwise measurements made by the eddy-covariance technique are used to estimate the errors of prior fluxes provided by the prognostic carbon-water-energy model ORCHIDEE. The results contradict the usual convenient assumption of a multivariate Gaussian distribution. The errors of ORCHIDEE have a heavier-tail distribution with a linear temporal dependency after the second lag day and no particular spatial structure. Such error distribution significantly complicates the inversion of CO 2 surface fluxes. Citation: Chevallier, F., N. Viovy, M. Reichstein, and P. Ciais (2006), On the assignment of prior errors in Bayesian inversions of CO 2 surface fluxes, Geophys.

Domaines: Océan, Atmosphère; Interfaces continentales, environnement

Frédéric Chevallier, Nicolas Viovy, Markus Reichstein, Philippe Ciais. On the assignment of prior errors in Bayesian inversions of CO 2 surface fluxes. Geophysical Research Letters, 2006, 33 (13), ⟨10.1029/2006GL026496⟩. ⟨hal-02924878⟩