0 cm/s 50

ECCO2: Eddying-ocean and sea-ice state estimationObjective: 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 mGreen’s function optimizationA 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 optimizationA second synthesis is being obtained using adjoint method to adjust ~109 model parameters during ARGO-rich period, 2004-present.

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 difference Optimized/data difference

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 meltingFreshwater 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 formationFreshwater input from basal melt decreases High Salinity Shelf Water production, which affects Antarctic Bottom Water production and meridional overturning.

Coupling with ISSMExperimental coupling with JPL/UCI ISSM is underway for improved estimates of ice shelf-ocean boundary conditions.