This consortium project is attempting to use all existing ocean observations, including particularly, satellite data, for the purpose of understanding and ultimately predicting, the ocean on climate time-scales. To this end it is advancing ocean state estimation as a practical, quasi-operational tool, for studying the ocean circulation and its influence on societal problems such as climate change, sea level rise, and biological impacts. Observing the ocean is difficult owing to its turbulent nature and very large range of energetic spatial scales. This project is establishing the means by which a quantitative description of the global ocean is and will be routinely and continuously available. The methodology employs state-of-the-art general circulation models, statistical estimation techniques, and the complete range of available oceanic observations, including, particularly, global satellite data, as well as in situ observations of all kinds. The effort includes further demonstration of the practical utility of ocean observing systems through their use in important scientific goals.