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NEMOVAR status and plans

Matt Martin, Dan Lea, Jennie Waters, James While, Isabelle Mirouze

NEMOVAR SG, ECMWF, Jan 2012.

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Outline

• Current status:

• NEMO-ASSIM

• NEMOVAR developments

• Status of NEMOVAR FOAM and GloSea hindcasts

• NEMOVAR in basin-scale 1/12 FOAM configurations

• Future plans:

• NEMOVAR in shelf-seas tidal FOAM configuration

• Operational implementation of NEMOVAR in FOAM and GloSea

• Developments for NEMOVAR

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NEMO-ASSIM

• In NEMO 3.4:

• documentation of the OBS and ASM code has been updated.

• tools (written by Kristian) for pre/post processing of the observation and feedback files have been included.

• IDL plotting utility with GUI (dataplot) has been included for use with observation and feedback files.

• All went into the code at the merge “party”.

• NEMO 3.4 now in beta release and user testing.

• Plan to test the new version before the end of the month.

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NEMOVAR developments

• Developments made for implementation in the ORCA025 configuration at NEMO vn3.2:

• error covariance development – see Jennie’s talk

• altimeter bias correction – see Dan’s talk

• restructuring of NEMOVAR control vector – see Dan’s talk.

• Sea-ice assimilation – see Dan’s talk

• SST bias correction – see James’ talk

• All code now in git repository, except for SST bias correction code (happy to put that in as well if people want it).

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NEMOVAR hindcasts

• FOAM ORCA025 hindcast:

• ORCA025L75, CICE configuration at NEMO v3.2 (basically the NOCS configuration and used by Hadley Centre for seasonal and longer-term predictions).

• Uses direct fluxes (not bulk formulae) from Met Office NWP.

• Period: 2008 – 2010.

• See Jennie’s talk for details, preliminary results and next steps.

• GloSea reanalysis:

• Same NEMO configuration as above, except fluxes from ERAInterim.

• Period: 1994 – present.

• Only just started it (done ~1 year).

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Regional FOAM configurations

• Preliminary work started on getting NEMOVAR working in 1/12 degree regional configurations.

• Plan to implement in N. Atlantic, Indian Ocean and Mediterranean models (no significant changes to these models compared to existing versions).

SST increments

•Started with Med. configuration (as it’s the smallest!).

•One small fix required to NEMOVAR code (lcross) but other than that, straightforward to do the initial set-up.

•Plan to do this for all 3 configs and to re-calculate the surface error covariances.

•Will then run some hindcasts to compare these with previous versions.

Rossby radius

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Future plans

Short-term plans:

• Complete ORCA025 implementation. Some further testing/tuning required.

• Implement improvements to altimeter bias correction scheme, including GOCE MDT.

• Implement NEMOVAR in regional FOAM configurations.

• Implement NEMOVAR SST assimilation in the Shelf-Seas NEMO model.

• Test NEMOVAR optimisations suggested by Met Office optimisation team.

Operational implementation:

• Operational implementation of NEMOVAR in global and regional FOAM configurations planned for September 2012.

• Operational implementation in GloSea will be after that, but hopefully in late 2012.

Longer-term developments:

• Anisotropic error covariances development – see Isabelle’s talk.

• Development of a diurnal SST analysis system – see James’ talk.

• Investigations into the issue of vertical velocity generation from physical DA.

• Work on coupled DA.

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