1. Experiences and expectations of NEMO
Giving an
Andrew C. Coward, Steve Alderson and Beverly de Cuevas

3. Benefits of NEMO: Curvilinear grids - tripolar

5. NEMO Users meeting : Thursday 22nd (afternoon) and Wednesday 23rd (morning) May 2007･
Coupled models
CICLE project at the CNRM - M. Lucas 

MERSEA project and ECMWF system 4 prototype - A. Troccoli 

First analyses of the new version of the sintex-F coupled model - C. De Boyer Montegut 

Progress on incorporating NEMO into the next Met Office climate model - C. Harris
Grid computing with ARPEGE-NEMO coupled model - E. Maisonnave
Operational Oceanography 

UK operational ocean forecasting with NEMO - A. Sellar 

1/12｡ ocean simulations with Mercator configurations - Y. Drillet 

The MERSEA/Mercator Ocean global 1/4｡ analysis and forecasting system V2 : first results - G. Garric
Implementing NEMO in the new version of the Mediterranean Forecasting Sytem - S. dobricic for P. Oddo
Biogeochemistry of the ocean
Iron and C13 in NEMO-PISCES - A. Tagliabue 

Biowaves project: first results from coupled physical/biogeochemical simulations in the N. Atlantic - G. Charria

Modeling the neodymium isotopic composition with the NEMO global ocean circulation model - T. Arsouze
Evidence for strong submesoscale variability of pCO2 in the northeast Atlantic Ocean - L. Resplandy
Developments / Portability
LIM3 a new sea ice model coupled to OPA - M. Vancoppenolle
Toward an alternative to the Leap Frog time stepping - M. Leclair
Impact of optimized calculation of Coriolis terms in the Mediterranean model set-up - S. dobricic 

An update on the OASIS coupler development - S. Valcke
Dynamics of the ocean
Decadal variability of oxygen, temperature and salinity in mode and intermediate waters - J. Clark 

SSS sensitivity in the Eastern North Atlantic subtropical gyre - B. Mourre 

Diagnosis of IGW in an OGCM : an intercomparison between numerical simulations and in situ-measurements - X. Levaillant (pdf)

Diagnosing the ocean control on the seasonal migration of the Marine ITCZ - A. Lazar

6. OCEANS 2025: Themes and selected scientific objectives
Theme 9: Next Generation Ocean Prediction Systems:
How sensitive are climate models to the manner in which sea ice is coupled?
Can nested models be trusted to give accurate results?
Can an ocean model be made energetically self-consistent?
What is the most appropriate level of complexity of biogeochemical models in climate studies?
Approaches and methodologies:
Develop NEMO as the core OGCM for use by the scientific community in the UK,
at resolutions of 1°, ¼°and 1/12°, and with nested grids (WP 9.10).
Develop an ocean model testbed permitting objective intercomparison and validation of a range
of ecosystem models, with a view to embedding the most promising in OGCMs (WP 9.11).

7. OCEANS 2025: Themes and selected scientific objectives
Theme 2: Marine Biogeochemical Cycles
To determine the sensitivity to future climate change of the mechanisms sustaining total nutrient
supply to the photic zone over the three major biomes of the North Atlantic.
Approaches and methodologies:
Quantify the magnitude and sensitivity of nutrient fluxes associated with winter overturning
and Ekman pumping. For overturning, this will be achieved using time-series stations,
Argo floats and mooring data together with previous studies and basin-scale simulations
(NEMO both at ¼º and with a smaller scale nested component at 1/12º in the North Atlantic).

8. OCEANS 2025: Themes and selected scientific objectives
Theme 1: Climate, Ocean Circulation, and Sea Level
Model simulations of climate change in the ocean
Identifying the causes of recent climate change in the ocean
Physical-biogeochemical budgets and mixing in the Southern Ocean (DIMES)
Research plan and deliverables:
2008: Completed simulation of changes in the ocean over the period obtained by
running NEMO globally at 1/4° resolution (and with a nested 1/12° North Atlantic grid)
using NCEP/NCAR (and possibly ECMWF) derived surface flux fields (WP 1.1b)

9. The UK is moving towards a more coordinated approach based on the NEMO model
This forms the core of “OCEANS 2025” with plans for (amongst others):
Global 1/4o models with biogeochemistry and 1/12o nested regions
Global 1/12o physics only model by 2010

10. Theme 9: NOCS NEMO activities
Produced global 1 degree NEMO configuration (ORCA1) [shared with UKMO]
Tested ORCA1 with “LOBSTER” NPZD model, about to test new NOCS biogeochemistry model “MEDUSA”
Developed “interpolation on the fly” option for handling surface forcing fields
Constructed ORCA1 forcing datasets which are compatible with those used with the current DRAKKAR (global 1/4o) model
Completed multi-decadal integrations of ORCA025
Developed capability to run AGRIF nests in sea-ice regions

11. Performance ORCA1: 15 processors : 3.59s per timestep (2.75yrs/day)
ORCA1: 32 processors with LOBSTER : 3.57s per timestep
ORCA025: 56 processors: Avg ts = ( 9 entries ) Min = Max =
(0.28yrs/day)
On HECToR:
ORCA025: 221 processors: Avg ts = 2.44 ( entries ) Min = 2.13 Max = 7.533
(1.6yrs/day)
16 processors 1.5s per timestep (~ 7 years/day)
64 processors 4.5s per timestep (~ 0.6 years/day)
512 processors 7.2s per timestep (~0.12 years/day)

12. Current status of Drakkar configurations
at NOCS
Steven Alderson, Andrew Coward, Beverly de Cuevas, Adrian New, George Nurser, Yevgeny Aksenov, Jeff Blundell, Jeremy Grist

13. Drakkar code with DFS3 forcing
N025_100 run (NOCS)
Drakkar code with DFS3 forcing
On-line interpolation of atmospheric fields
cdmp = (5 times weaker than G70)
icedmp = 25 (same as G70)
(currently1997)

18. Drake Passage and Bering Strait transport comparison
ORCA025_G

20. Complete and analyse N025_100 Investigate CICE vs LIM3
NOCS plans for 2008
Complete and analyse N025_100
Investigate CICE vs LIM3
Extend tests with AGRIF in North-west Atlantic
Run ORCA025 with biogeochemistry

21. Experiments with AGRIF at NOCS
Steven Alderson
Oceans 2025
Work Package 2.5:
“… NEMO will be run globally at 1/4° with biogeochemistry and with a higher resolution 1/12° nested model ….”

22. AGRIF nesting
Bathymetry
data
Nesting
tools
T/S data

23. NEMO conversion to AGRIF
routine
AGRIF/NEMO
code
AGRIF/
NEMO
AGRIF
interface routines
AGRIF
library

24. Order-1 nest in 1° global NEMO

25. Order-1 nest in 1° model: surface differences (30d)
Ice rheology

26. Schematic for calculation of fluxes at water surface
Outer model
Nest (modified)
Example flux variables in red

27. Order-1 nest in 1° model: surface differences (30d)
Empty boxes for ssheig and soicecov

28. 1° model vs order-3 nest in 1° model: SST (4mnth)
latitude
longitude
longitude

29. No nest model vs order-3 nest in 1° model
Top row: Mediterranean, bottom row: Gulf Stream
1st column 1deg model no nest; 2nd + 3rd columns 1deg model with factor 3 nest

30. Further work Continuity across restart files
Higher resolution run (standard mpi_send)
Blanking of areas (e.g. Pacific)
AGRIF with biogeochemical models
Southern Ocean region
IBM 2560 processors running AIX