A few references
¥Vukicevic, T., B.H. Braswell and D.S. Schimel.  2001.  A diagnostic study of temperature controls on global terrestrial carbon exchange. Tellus (B)  53:150-170. (variational)
¥Braswell, B.H., W.J. Sacks, E. Linder and D.S. Schimel.  2004.  Estimating ecosystem process parameters by assimilation of eddy flux observations of NEE.  Global Change Biol. 11:335-355 (MCMC)
¥Williams, M. Schwarz, B.E. Law, J. Irvine, and M.R. Kurpius. 2005. An improved analysis of forest carbon dynamics using data assimilation. Glov=bal Change Biol. 11:85-105 (EKF)
¥Wang, Y-P. and D Barrett. 2003. stimating regional terrestrial carbon fluxes for the Australian continent using a multiple-constraint approach. I. Using remotely sensed data and ecological observations of net primary production. Tellus (B) 55:270-289 (Synthesis inversion)