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On one year adjoint/Argo estimates. Forget, Ferron, Mercier 08 (Oc. Mod.) Forget, Mercier, Ferron 08 (Oc. Mod.) Forget 09 (JPO, in rev.) Maze, Forget, Buckley, Marshall 09 (JPO, in rev.) Forget, Maze, Buckley, Marshall 09 (to be subm.). Gael Forget - PowerPoint PPT Presentation
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On one year adjoint/Argo estimates
On one year adjoint/Argo estimates
Gael Forget
MIT, EAPS Sept 23, 2008 ECCO2
Gael Forget
MIT, EAPS Sept 23, 2008 ECCO2
• Forget, Ferron, Mercier 08 (Oc. Mod.)• Forget, Mercier, Ferron 08 (Oc. Mod.)• Forget 09 (JPO, in rev.)• Maze, Forget, Buckley, Marshall 09 (JPO, in rev.)• Forget, Maze, Buckley, Marshall 09 (to be subm.)
Period of interest:
Argo rich period, from ~2004
much consolidated data base for those recent years
room for better understanding of ocean behavior.
Incentive for GCM-interpolation:
complement obs. constraints with dyn./atm. constraints
and extend interpretation of observations.
Objection to GCM-interpolation:
errors in dyn./atm. may prevent close fit to obs.
a basic matter of balance amongst the various constraints.
What is the trade-off in 1 year adjoint estimates:
+ rather large data base over one year
+ relatively easy to achieve close fit to obs.
+ (-?) GCM dynamics imposed up to seasonal cycle
- (+?) adjustments to dynamics for longer time-scales
Some success with 1 degree resolution, global, over 2004-5-6.
close fit to obs.
extended interpretation of observation
… eddying follow on.
achieving a close fit to Argo
ECCO2-ArgoWOA01-Argo
Misfit to Argo T, 300m, 2004-2006
Misfit to Argo T, 300m, 2004-2006
ECCO2-ArgoECCO1.3-Argo
Misfit to Argo T, 300m, 2004-2006
Misfit to Argo T, 300m, 2004-2006
OCCA-ArgoECCO1.3-Argo
Misfit to Argo T, 300m, 2004-2006
Misfit to Argo T, 300m, 2004-2006
Extended interpretation of observations
EDW layer at the surfaceEDW layer at the surface
17
1918Sept March
17
1918
19
17
GCM-interpolated profiles
| 04 | 05 | 06 |
EDW layer below the surface
EDW layer below the surface
1917
ARGO profiles
| 04 | 05 | 06 |
0
200
400
600
800
Air-Sea Heat Flux Ocean Mixing
Divergent Flow Volume Change
EDW layer volume budgetEDW layer volume budget
… eddying follow on
From Green’s function to Adjoint:
practical for large dimension problem
well-adjusted to both regional & global fitting
1 year, global, 1/6 degree:
manageable computational cost
fairly close fit, water mass studies, etc.
Components in practice
Adjoint ok for cube sphere
Line Search ok offline
Controls ok for Init./forcing/mixing
Observations same as for 1 degree (?)
Error covariances same as for 1 degree (?)
first guess/spin-up start from 1 degree results
year
X-Xmean
13 years
5000
m
ECCO1.2
3 years
OCCA
13 years 3 years
ECCO1.2 OCCA
year
X-Xmean
13 years 3 years
ECCO1.2 OCCA
EDW layer 17<T<19°CEDW layer 17<T<19°C
EDW layer in Argo profilesEDW layer in Argo profiles
EDW layer in model profiles
EDW layer in model profiles
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