1. 0 cm/s 50 ECCO2: Eddying-ocean and sea-ice state estimation Objective: synthesis of global-ocean and sea-ice data that covers full ocean depth and that permits eddies. Motivation: understand recent evolution of polar oceans, monitor time-evolving term balances within and between different components of Earth system, improved estimates of ocean carbon cycle, etc. Current speed @ 15 m Green’s function optimization A first eddying, global ocean and sea ice synthesis for period 1992-2007 was obtained using a Green’s Function approach to adjust a small number ( ∼ 80) of model parameters. Adjoint method optimization A second synthesis is being obtained using adjoint method to adjust ~10 9 model parameters during ARGO-rich period, 2004-present.

2. Assessment of ECCO2 solution in Arctic Ocean (A. Nguyen, D. Menemenlis & R. Kwok) Arctic cost function reduction Canada Basin Hydrography 2007-2008 summer sea ice minima Sea ice velocity comparison with SSM/I Baseline/data differenceOptimized/data difference

3. Modeling of ice shelf-ocean interactions ECCO2 ice shelf cavity melt rate (M. Schodlok & D. Menemenlis) ISSM land ice surface velocity (E. Rignot, E. Larour, M. Morlighem & H. Seroussi) melt rate (m/yr) velocity (m/yr) ECCO2 estimates of basal melting Freshwater flux (59 mSv or 1600 Gt/a) is double previous (BRIOS) estimates, more consistent with mass loss derived from ICESat/GLAS data (55 mSv), comparable in size with iceberg calving (2000 Gt/a). Antarctic Bottom Water formation Freshwater input from basal melt decreases High Salinity Shelf Water production, which affects Antarctic Bottom Water production and meridional overturning. Coupling with ISSM Experimental coupling with JPL/UCI ISSM is underway for improved estimates of ice shelf-ocean boundary conditions.