Lee, T., D. Stammer, and (in alphabetical order) T. Awaji, M. Balmaseda, D. Behringer, J. Carton, N. Ferry, A. Fischer, I. Fukumori, B. Giese, K. Haines, E. Harrison, P. Heimbach, M. Kamachi, Christian Keppenne, A. Köhl, S. Masina, D. Menemenlis, R. Ponte, E. Remy, M. Rienecker , A. Rosati, J. Schroeter, D. Smith, A. Weaver, C. Wunsch, Y. Xue, 2009. Ocean State Estimation for Climate Research. Community White Paper for OceanObs'09, Venice, Italy, 21-25 September 2009. ESA Special Publication, in press.