1. Current state of ECHAM5/NEMO coupled model Wonsun Park, Noel Keenlyside, Mojib Latif (IFM-GEOMAR) René Redler (NEC C&C Research Laboratories) DRAKKAR meeting 25-26 January 2007, Grenoble, France

2. Outline Overview of the coupled model 500-yr long simulations Current state Summary and outlook

3. Overview of KCM Kiel Climate Model (KCM): ECHAM5/NEMO coupled model Component models –AGCM: ECHAM5 (T31L19, T63L31, T106L31), IPCC version –OGCM: NEMO (ORCA2 standard, ORCA05- DRAKKAR configuration), V1_12, NEMO2 –Coupler: OASIS3 or OASIS4 within PRISM

4. Two 500-yr experiments Same ORCA2 configuration –NEMO v1_12 –Standard parameters –LIM parameters (hiccrit=0.3,0.6; angvg=-15) Different ECHAM5 tuning parameters –T31L19 resolution –P53: IPCC cloud scheme and parameters –P57: New cloud scheme (Tompkins, 2002)

5. MOC 30N Drake passage P57 New cloud scheme P53 IPCC parameters 15 13 11 9 7 160 140 120 100 80 60 Transport (11-yr runavg) 15 13 11 9 7 160 140 120 100 80 60

6. TOA Radiation & 2m-temp 1.5 1.0 0.5 [W/m 2 ] P53 IPCC parameters P57 New cloud scheme

7. SST biases P57 New cloud scheme P53 IPCC parameters

8. Nino3 spectra 51mn 34mn

9. Equatorial annual cycles Observation New cloud IPCC parameters

10. Sea ice Ice area [10 6 km 2 ] Fraction [%], March Thickness [m], March

11. angvg=-25 T25 angvg=25 Ice dynamics test T25 ang=0 no islands Adopting turning angle of ice drift Removing island? Canadian archipelago: hydrological model change, redigitizing?

12. Current coupling scheme NEMO2 Separate choice of angvg for NH and SH Preliminary hydrological model tuning in ECHAM5 concerning Canadian archipelago (need further investigation for changing mask in ORCA2?) All Albedos unified in ECHAM5 (sea ice as well) Coupling time step: 1x, 4x, 12x/day Variable exchanged –Ocean to atmosphere (7): SST, sea ice fraction, sea ice thickness, snow thickness, sea ice temperature, zonal-, meridional- ocean velocity –Atmosphere to ocean (11): U-, V- wind stresses on u- and v-grids, total P-E, solid P-E, solar- and non-solar heat flux over water and ice, non-solar heat flux derivative

13. Current run 13Sv 1 yr 150 MOC 30N Ice area Ice cover and thickness

14. Ongoing analysis Tropical variability from ECHAM5/NEMO coupled model (Paper in preparation) ENSO and MOC relationship on multidecadal scales Freshwater variability and MOC (with comparison to T42, T63 atmosphere) Comparison with existing standalone ORCA2 simulations

15. Summary and outlook KCM prototype is available for coordinated experiments with standalone NEMO Two 500-yr long simulations with difference atmosphere configurations: –Stable climate ( <1 W/m 2 TOA net radiation) –Importance of atmosphere forcing to ENSO spectra –Still low MOC, cold bias over North Atlantic YR2007: Constructing higher resolution model –ECHAM5 T63L31/T106L31 coupled to ORCA05 DRAKKAR configuration, OASIS4 –Standalone ECHAM5, NEMO, and coupled model experiments following scientific interests

16. Thanks

17. Mixed layer depth Previous (P57) Current

18. Meridional Overturning Circulation & Antarctic Circumpolar Current P53 J64 MOC ACC 9Sv 95Sv 13Sv 110Sv