Objectives Review work done on impact studies, OSEs and OSSEs over the past years Identify robust and common features Understand differences in assimilation systems Provide good examples of the contribution of observing systems Provide preliminary recommendations on observing system design Define and agree on activities to be carried out before the GODAE final symposium Develop new ideas on the way to assess and design the ocean observing systems and propose new experiments to be carried out in the coming years GODAE-OOPC OSSE/OSE Workshop Paris, November

GODAE/OOPC OSE/OSSE workshop Outcomes –Very good talks and discussion. New ideas. –OSE/OSSE in the ocean are still at the early stage. Science& technical issues: High resolution/mesoscale versus large scale/climate What needs to be optimized (SST, surface currents, full ocean state, analysis or forecast) ? -Good demonstrations of impact of Argo and altimetry (high resolution) exist. To be developed and extended to other elements of the global ocean observing system + links towards applications -Setting up of a Working Group in 2008 – strong links with the intercomparison WG. Synthesis paper / final symposium –Efforts need to be organized and experiences need to be shared –International collaboration required – Long term activity/post GODAE working group ?

Observing systems and OSE/OSSEs A few messages that should be conveyed at the final symposium Critical importance of observing systems Altimetry. The importance of high resolution. 3 to 4 altimeters and a long term reference (Jason). Evolution with respect to GODAE initial requirements. Role and importance of the in-situ global ocean observing system. Major impact of Argo in GODAE data assimilation systems. Role of salinity. High resolution SST is required. Role/contribution of GHRSST Need sustained observing systems (research, climate and applications). We will need good examples of the impact of observing systems. A priority for the IGST !