Summary of January 2007 ECCO2 meeting Overview and Motivation ECCO, ECCO-GODAE, ECCO2 (Wunsch, MIT) The only way to understand the complete, global, time- evolving ocean circulation is to use all available data and all available theory. ECCOn seeks the best possible estimate of the time-evolving ocean circulation, its influence on climate, chemistry, biology, etc., understanding of predictability, and determination of what we do not understand. A two+ generation problem! ECCO2 and NASA satellite missions (Fu, JPL) Observations of mesoscale and sub-mesoscale ocean variability are a key requirement for understanding regional and global climate processes. For this reason, wide swath altimetry has been endorsed by the NRC Decadal Survey as a possible new NASA mission. ECCO2 provides a framework for utilizing high-resolution data from existing and future NASA satellite missions. Estimated sea level trend, spatial mean removed (Wunsch, Ponte, and Heimbach, 2007). Ground tracks of TOPEX/Jason tandem mission superimposed on satellite imagery of sea surface temperature.

Summary of January 2007 ECCO2 meeting Assimilation and Modeling Towards an ECCO2 release (Menemenlis/Zhang, JPL) A first least squares minimization of the global-ocean and sea-ice cube sphere (CS510) model resulted in a 64% decrease of cost function wrt temperature and salinity climatologies. These state estimates are already being used in a host of science applications Eddy permitting state estimation (Heimbach/Mazloff, MIT) Adjoint method state estimation in the presence of vigorous mesoscale eddy variability has been shown to be possible in a regional, high-resolution, Southern Ocean model configuration. ECCO2 high resolution modeling (Hill, MIT) High-resolution global-ocean and sea-ice simulations are being used to estimate error statistics, to experiment with multiscale assimilation, to improve parameterizations of unresolved processes, and to drive the development of petabit/petaflop infrastructure.

Summary of January 2007 ECCO2 meeting Core Technologies MITgcm model development (Campin, MIT) Advection schemes (Adcroft, GFDL) Sea-ice modeling (Menemenlis, JPL) ECCO2 coupled modeling (Hill, MIT) OpenAD adjoint compiler (Utke, Chicago) ECCO activities at Harvard (Gebbie, Harvard) ECCO2 web site (Menemenlis, JPL) Concurrent visualization (Henze, Ames)

Summary of January 2007 ECCO2 meeting Early User Applications Subtropical mode water (Maze, MIT) Eddy propagation velocity (Fu, JPL) GRACE data constraints (Zlotnicki, JPL) Errors estimates (Forget, MIT) Eddy parameterizations (Ferreira, MIT) Arctic freshwater budget (Condron, WHOI) Arctic sea ice budget (Kwok, JPL) Sea ice data/model comparison (Nguyen, JPL) Carbon cycle modeling (Manizza, MIT) Eddy variability in Indian Ocean (Lee, JPL) Darwin project (Hill, MIT) Southern Ocean (Schodlok, JPL) MITgcm assimilation efforts (Cornuelle, SIO) Adjoint assimilation efforts (Edwards, UCSC )

Summary of January 2007 ECCO2 meeting Plans for 2007 Public release of first ECCO2 solution in Summer Preliminary analyses of ECCO2 solution and sensitivity experiments. Development of embedded high-resolution regional models. First coupling of ECCO2 with Goddard GEOS-5 atmospheric model. High-end visualizations and interactive multi-variate displays. Improved ECCO2 web site and distribution capability. Model development: Improved grids, hydro-dynamical kernel, representation of sea-ice, ice-shelf processes, stirring and mixing. Fall 2007 follow-up meeting at MIT.