E. Andersson, M. Fisher, R. Munro, and A. Mcnally, Diagnosis of background errors for radiances and other observable quantities in a variational data assimilation scheme, and the explanation of a case of poor convergence, Q. J. R. Meteorol. Soc, vol.126, pp.1455-1472, 2000.

D. F. Baker, S. C. Doney, and D. S. Schimel, Variational data assimilation for atmospheric CO 2, Tellus, Ser. B, vol.58, pp.359-365, 2006.

P. Bousquet, P. Peylin, P. Ciais, C. Quere, P. Friedlingstein et al., Regional changes in carbon dixiode fluxes of land and oceans since, Science, vol.290, pp.1342-1346, 1980.

F. M. Bréon, D. M. O'brien, and J. D. Spinhirne, Scattering layer statistics from space borne GLAS observations, Geophys. Res. Lett, vol.32, p.22802, 2005.

F. Chevallier, R. J. Engelen, and P. Peylin, The contribution of AIRS data to the estimation of CO 2 sources and sinks, Geophys. Res. Lett, vol.32, p.23801, 2005.
URL : https://hal.archives-ouvertes.fr/bioemco-00175978

F. Chevallier, M. Fisher, P. Peylin, S. Serrar, P. Bousquet et al., Inferring CO 2 sources and sinks from satellite observations: Method and application to TOVS data, J. Geophys. Res, vol.110, p.24309, 2005.
URL : https://hal.archives-ouvertes.fr/bioemco-00175976

F. Chevallier, N. Viovy, M. Reichstein, and P. Ciais, On the assignment of prior errors in Bayesian inversions of CO 2 surface fluxes, Geophys. Res. Lett, vol.33, p.13802, 2006.
URL : https://hal.archives-ouvertes.fr/hal-02924878

P. Ciais, Europe-wide reduction in primary productivity caused by the heat and drought in 2003, Nature, vol.437, pp.529-533, 2005.
URL : https://hal.archives-ouvertes.fr/insu-00373792

P. Courtier, J. Thepaut, and A. Hollingworth, A strategy for operational implementation of 4D-Var using an incremental approach, Q. J. R. Meteorol. Soc, vol.120, pp.1367-1387, 1994.

D. Crisp, The Orbiting Carbon Observatory (OCO) mission, Adv. Space Res, vol.34, issue.4, pp.700-709, 2004.
URL : https://hal.archives-ouvertes.fr/hal-02924533

J. C. Derber and F. Bouttier, A reformulation of the background error covariance in the ECMWF global data assimilation system, Tellus, Ser. A, vol.51, pp.195-221, 1999.

G. Desroziers, P. Brousseau, and B. Chapnik, Use of randomization to diagnose the impact of observations on analyses and forecasts, Q. J. R. Meteorol. Soc, vol.131, pp.2821-2837, 2005.

I. G. Enting, Inverse Problems in Atmospheric Constituent Transport, 2002.

I. G. Enting, C. M. Trudinger, and R. J. Francey, A synthesis inversion of the concentration and d 13 C atmospheric CO 2, Tellus, Ser. B, vol.47, pp.35-52, 1995.

M. Fisher, Minimization algorithms for variational data assimilation, Seminar on Recent Developments in Numerical Methods for Atmospheric Modelling, pp.364-385, 1998.

M. Fisher, Estimation of entropy reduction and degrees of freedom for signal for large variational analysis systems, Eur. Cent. for Medium-Range Weather Forecasts, vol.397, 2003.

M. Fisher and P. Courtier, Estimating the covariance matrices of analysis and forecast error in variational data assimilation, ECMWF Tech. Memo. 220, 35 pp., Eur. Cent. for Medium-Range Weather Forecasts, 1995.

S. Generoso, F. F.-m.-bréon, Y. Chevallier, M. Balkanski, I. Schulz et al., Assimilation of POLDER aerosol optical thickness into the LMDz-INCA model: Implications for the Arctic aerosol burden, J. Geophys. Res, vol.112, p.2311, 2007.
URL : https://hal.archives-ouvertes.fr/hal-02872413

K. R. Gurney, Towards robust regional estimates of CO 2 sources and sinks using atmospheric transport models, Nature, vol.415, pp.626-630, 2002.
URL : https://hal.archives-ouvertes.fr/hal-02888447

F. Hourdin and A. Armengaud, Test of a hierarchy of finite-volume schemes for transport of trace species in an atmospheric general circulation model, Mon. Weather Rev, vol.127, pp.822-837, 1999.

S. Houweling, I. F.-m.-bréon, C. Aben, M. Rödenbeck, M. Gloor et al., Inverse modeling of CO 2 sources and sinks using satellite data: A synthetic inter-comparison of measurement techniques and their performance as a function of space and time, Atmos. Chem. Phys, vol.4, pp.523-538, 2004.
URL : https://hal.archives-ouvertes.fr/hal-00328362

S. Houweling, W. Hartmann, I. Aben, H. Schrijver, J. Skidmore et al., Evidence of systematic errors in SCIAMACHY-observed CO 2 due to aerosols, Atmos. Chem. Phys, vol.5, pp.3003-3013, 2005.
URL : https://hal.archives-ouvertes.fr/hal-00328411

K. Ide, P. Courtier, M. Ghil, and A. C. Lorenc, Unified notation for data assimilation: Operational, sequential and variational, J. Meteorol. Soc. Jpn, vol.75, pp.181-189, 1997.

, Climate Change 2001: The Scientific Basis, Intergovernmental Panel on Climate Change, 2001.

M. Janisková, J. Mahfouf, J. Morcrette, and F. Chevallier, Linearized radiation and cloud schemes in the ECMWF model: Development and evaluation, Q. J. R. Meteorol. Soc, vol.128, pp.1505-1528, 2002.

S. Lafont, L. Kergoat, G. Dedieu, A. Chevillard, E. Kjellström et al., Spatial and temporal variability of land CO 2 fluxes estimated with remote sensing and analysis data over western Eurasia, Tellus, Ser. B, vol.54, pp.820-833, 2002.

A. C. Lorenc, Optimal nonlinear objective analysis, Q. J. R. Meteorol. Soc, vol.114, pp.205-240, 1988.

R. Ménard, S. E. Cohn, L. Chang, L. Lang-ping, and P. M. Lyster, Assimilation of stratospheric chemical tracer observations using a Kalman filter. part I: Formulation, Mon. Weather Rev, vol.128, pp.2654-2671, 2000.

D. M. O'brien and P. J. Rayner, Global observations of the carbon budget: 2. CO 2 column from differential absorption of reflected sunlight in the 1.61 mm band of CO 2, J. Geophys. Res, vol.107, issue.D18, p.4354, 2002.

J. G. Olivier, A. F. Bouwman, C. W. Van-der-maas, J. J. Berdowski, C. Veldt et al., Description of EDGAR version 2.0. A set of global emission inventories of greenhouse gases and ozone-depleting substances for all anthropogenic and most natural sources on a per country basis and on 1 Â 1 grid, 1996.

B. C. Pak and M. J. Prather, CO 2 source inversions using satellite observations of the upper troposphere, Geophys. Res. Lett, vol.28, pp.4571-4574, 2001.

P. K. Patra, S. Maksyutov, Y. Sasano, H. Nakajima, G. Inoue et al., An evaluation of CO 2 observations with Solar Occultation FTS for Inclined-Orbit Satellite sensor for surface source inversion, J. Geophys. Res, vol.108, issue.D24, p.4759, 2003.

F. Rabier and P. Courtier, Four-dimensional assimilation in the presence of baroclinic instability, Q. J. R. Meteorol. Soc, vol.118, pp.649-672, 1992.

P. J. Rayner and D. M. O'brien, The utility of remotely sensed CO 2 concentration data in surface source inversions, Geophys. Res. Lett, vol.28, pp.175-178, 2001.

P. J. Rayner, R. M. Law, D. M. O'brien, T. M. Butler, and A. C. Dilley, Global observations of the carbon budget: 3. Initial assessment of the impact of satellite orbit, scan geometry, and cloud on measuring CO 2 from space, J. Geophys. Res, vol.107, issue.D21, p.4557, 2002.

C. Rödenbeck, Estimating CO 2 sources and sinks from atmospheric mixing ratio measurements using a global inverse of atmospheric transport, MPI-BGC Tech. Rep, vol.6, 2005.

C. Rödenbeck, S. Houweling, M. Gloor, and M. Heimann, CO 2 flux history 1982 -2001 inferred from atmospheric data using a global inversion of atmospheric transport, Atmos. Chem. Phys, vol.3, pp.1919-1964, 2003.

C. D. Rodgers, Inverse Methods for Atmospheric Sounding: Theory and Practice, vol.238, 2000.

W. B. Rossow, A. W. Walker, D. E. Beuschel, and M. D. Roiter, International Satellite Cloud Climatology Project (ISCCP) documentation of new cloud datasets, World Meteorol. Organ, vol.115, 1996.

R. Sadourny and K. Laval, January and July performance of the LMD general circulation model, New Perspectives in Climate Modeling, pp.173-197, 1984.

M. Sottocornola and G. Kiely, An Atlantic blanket bog is a modest CO 2 sink, Geophys. Res. Lett, vol.32, p.23804, 2005.

T. Takahashi, Global sea-air CO 2 flux based on climatological surface ocean pCO2, and seasonal biological and temperature effect, Deep Sea Res., Part II, vol.49, pp.1601-1622, 2002.

O. Talagrand, A posteriori evaluation and verification of analysis and assimilation algorithms, paper presented at Workshop on Diagnosis of Data Assimilation Systems, Eur. Cent. for Medium-Range Weather Forecasts, pp.2-4, 1998.

Y. Trémolet, Diagnostics of linear and incremental approximations in 4D-Var, Q. J. R. Meteorol. Soc, vol.130, pp.2233-2251, 2005.

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F. Bréon, F. Chevallier, and P. J. Rayner, Laboratoire des Sciences du Climat et de l'Environnement