

Pinty, B, Lavergne, T, Vossbeck, M, Kaminski, T, Aussedat, O, Giering, R, Gobron, N, Taberner, M, Verstraete, MM, Widlowski, JL (2007). Retrieving surface parameters for climate models from Moderate Resolution Imaging Spectroradiometer (MODIS)Multiangle Imaging Spectroradiometer (MISR) albedo products. JOURNAL OF GEOPHYSICAL RESEARCHATMOSPHERES, 112(D10), D10116. Abstract [1] We present a computerefficient software package enabling us to assimilate operational remotesensing flux products into a stateoftheart twostream radiation transfer scheme suitable for climate models. This package implements the adjoint and Hessian codes, generated using automatic differentiation techniques, of a cost function balancing ( 1) the deviation from the a priori knowledge on the model parameter values and ( 2) the misfit between the observed remotesensing fluxes and the twostream model simulations. The individual weights of these contributions are specified notably via covariance matrices of the uncertainties in the a priori knowledge on the model parameters and the measurements. The proposed procedure delivers a Gaussian approximation of the PDFs of the retrieved model parameter values. The a posteriori covariance matrix is further exploited to evaluate, in turn, the posterior probability density functions of the radiant fluxes simulated by the twostream model, including those that are not measured, for example, the fraction of radiation absorbed in the ground. Applications are conducted using Moderate Resolution Imaging Spectroradiometer ( MODIS) and Multiangle Imaging Spectroradiometer (MISR) broadband surface albedo products. It turns out that the differences between these two albedo sets may translate into discernible signatures on some retrieved model parameters. Meanwhile, adding the Joint Research Centre (JRC)Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) Seaviewing Wide Fieldofview Sensor (SeaWiFS) products into the measurements yields a significant reduction of uncertainties. Results from these applications indicate that the products retrieved from the twostream inversion procedure ( 1) exhibit much less variability than those generated by the operational algorithms for the LAI and FAPAR, and ( 2) are in good agreement with the available groundbased estimates. DOI: 10.1029/2006JD008105 ISSN: 01480227 