The ECCO 1 degree global WOCE Synthesis. The Estimated Mean State A. Koehl, Y. Lu, P. Heimbach, B. Cornuelle, D. Stammer and C. Wunsch for the ECCO Consortium. The global time-dependent WOCE data synthesis made by the ECCO Consortium over the 10-year period 1992 - 2001 aims at estimating the time-dependent ocean state that is, within error bars, consistent with the global data sets and the dynamics imbedded in the numerical model. We compare the estimated state with the WOCE observations that went into the synthesis. Overall, the agreement with the data is close to consistent with the prior error statistics for the data and model. The remaining misfit and a comparison with the reference state provides information about the quality of both the state and about and model errors. The state estimation procedure is able to correct for many of the traditional shortcomings of the flow field. However, as adjustments are made through changing the surface boundary conditions and initial conditions only, not all deficits can be properly represented. Mean meridional heat transports, meridional overturning and volume transport through passages are slightly reduced in comparison with the unconstrained reference run.