Coupled & Ocean Modelling @ MPI-M

1. Coupled & Ocean Modelling @ MPI-M Johann Jungclaus Max-Planck-Institut für Meteorologie

2. Ocean model development at MPI-M has presently two foci: Maintain and improve the Max Planck Institute Ocean Model (MPIOM) as part of the MPI-M Earth System Model (E. Maier-Reimer, H.Haak, J. Jungclaus, J-S. v. Storch) Develop a new ocean model in co-operation with new atmosphere model ICON (P. Korn, S. Lorenz, PhD students)

3. The MPI-M Earth System Model Anthropogenic forcing Natural forcing CH4, N2O, CFC conc. Volcanic aerosol CO2 emissions Solar variations Land use change AtmosphereECHAM5/6 Momentum, Energy, H2O, CO2 OceanMPIOM HAMOCC LandHD JSBACH

4. The MPI-M Earth System Model • ECHam5/6 (Roeckner et al., 2003), interactive runoff and glacier calving scheme. • Land surface JSBACH (Raddatz et al., 2007), Dynamic Vegetation (Brovkin et al., 2009) • New Radiation • Resolution: T31L19, T63L47, T127/L95, ….. • OASIS 3.0 coupler • MPIOM

5. MPIOM • MPIOM (Marsland et al., 2003), • C-Grid, z-level, partial cells, BBL parameterization • Isopycnal diffusion, GM (Gent et al., 1995; Griffies et al., 1998) • Vertical mixing: PP and mixed layer wind mixing • Hibler-type sea ice model incl. snow and fractional ice cover • Conformal mapping grid: dipole or tripole • Ocean biogeochemistry module HAMOCC5 (Wetzel et al., 2007)

6. MPIOM- grid set-upsdipole grid dipole global application: GR3.0 and GR1.5 dipole regional application

7. tripole grid set-up Tri-polar, quasi-homogeneous 1°, 0.4°, 0.1°

8. Paleo applications PETM (55 Ma) PhD thesis M. Heinemann dipole grid Miocene (15 Ma) PhD thesis M. Krapp tripole grid

9. Resolution matters Griffies et al., 2009 MPIOM: TP04

10. Resolution matters (sometimes…) Griffies et al., 2009 MPIOM: TP04

11. Applications long (and, or many) integrations with effective low-resolution ESM (T31/GR3) Ensemble simulations of the Last Millennium Multi-millennia transient experiments (e.g. Holocene) Sensitivity experiments in paleo environment (e.g., PETM, Miocene)

12. Example: Last Millennium first ensemble simulations over the last 1200 years using comprehensive ESM including interactive carbon cycle. (In total, almost 20000 years of data!)

13. Northern Hemisphere temperatures:the instrumental period HadCRUT2v CRUTEM2v Expt. 1 Expt. 2 Expt. 3 Expt. 4 Expt. 2 anomalies w.r.t. 1961-1991 mean • Simulation captures warming trend over 19th/20th century • Observed multidecadal variations partly due to internal variability

14. Northern Hemisphere temperatures:the last 1200 years Background shading: overlay of reconstructions (after IPCC, 2007) solid: 5 full forcing expts. (Krivova solar 0.1%) dashed: 3 full forcing expts. (Bard solar 0.25%) • Range of variability consistent with observations, but LIA cooling less pronounced than in reconstruction for 0.1%

15. Simulation of CO2 evolution Solid lines: full forcing ensemble E1 (Krivova solar, 0.1%) dashed lines: full forcing ensemble E2 (Bard solar, 0.25%) Grey shading: Overlap of reconstructions (C. Reick)

16. Applications Decadal prediction and ocean initialization No data assimilation for MPIOM available, but benefit from Detlef Stammer‘s GECCO work in the neighborhood Presently testing several „assimilation“ techniques in AR4 set-up (ECHAM5 T63L31 MPIOM GR1.5L40) : SST (Keenlyside et al., 2008), GECCO (Pohlmann et al., 2009) Forced (NCEP) MPIOM runs (Matei et al., in prep.)

17. SAT hind minus 20C COR skill for lead time 1yr NCEP GECCO Gain in skill

18. NCEP GECCO SAT hind minus 20C COR skill for yr6-10 Gain in skill

19. MPIOM at high resolution (0.1°) • STORM-project (J.S. v. Storch) • using IPCC AR5 model system (ECHAM6/MPIOM-TP) • long climate change simulations (i.e., 20 century run + 21 century run with RCP4.5 forcing) • horizontal resolution in the ocean: ~ 1/10 degree (10km) • horizontal resolution in the atmosphere: ~ 50 km Scientific foci (among others): - Climate sensitive & dependence of climate sensitive on resolution (e.g. whether and to what extent will climate projections change due to enhanced resolution) - Impact studies (e.g. changes of extreme value statistics…)

20. a snapshot of horizontal velocity speed at 57 m [m/s]

21. MPI-M will run CMIP5 experiments 20th century, projections, and decadal forecast using ECHAM6 T127/L95 MPIOM 0.4/L80 „HR“ Paleo and historic (last millennium) will be run at T63L47 (ECHAM6) and 1°L40 (MPIOM) „LR“ Expts with interactive chemistry will be run at „LR“ at FZ Jülich (M. Schultz) ECHAM6/MPIOM in CMIP5

22. CMIP5 ECHAM6/MPIOM-HR C: CORE, T1: Tier1, T2: Tier 2

23. CMIP5 ECHAM6/MPIOM-HR C: CORE, T1: Tier1, T2: Tier 2

24. CMIP5 ECHAM6/MPIOM-HR C: CORE, T1: Tier1, T2: Tier 2

25. CMIP5 ECHAM6/MPIOM-LR C: CORE, T1: Tier1, T2: Tier 2

26. Working fields Tides (E. Maier-Reimer, M. Müller) New sea ice model (D. Notz) Vertical mixing (E. Exarchou, J. v. Storch, JHJ) Adaptation for high resolution (0.1° or higher) models (non-hydrostatic, non-boussinesq (E. Maier-Reimer))

27. Tides • Ephemeridic module of Thomas et al. [2001] implemented in MPIOM • Analytical ephemerides for the sun and moon calculated with sufficient accuracy for tidal applications (~0.1‘ for the sun, 1-2‘ for the moon)‏[van Flandern and Plukkinen, 1998] • Real-time forcing of complete lunisolar tidal potential

28. New sea-ice model A representation of the frazil-pancake cycle and the associated brine release An improved representation of salt fluxes from ice during growth and decay Multi-layer, multi-category sea-ice thermodynamics Improved albedo scheme (Pedersen et al., 2009) Dynamics on triangular grid for ICON is planned The new sea-ice model will include:

29. Coupled atmosphere & ocean model on identical grid type Icosahedral grid: unstructured grid that avoids problems of lat/lon grids: pole singularity, non-uniformity of grid cells Collaboration with German Weather Service (DWD) Includes data assimilation Joint pool of physics packages Fromshort & local to long & global time-space scales weather and climate prediction Local model refinement: horizontal & vertical regional/local modelling covering hydrostatic & nonhydrostatic regime ICON: MPI-M's Next Generation Climate Model

30. ICON Development Branches 2D shallow water 3D hydrostatic atmos. dynamical core 3D hydrostatic ocean 3D non-hydrostatic numerics ICOHAMas successor ofECHAM + ECHAM physics

31. The ICON Grid Concept of patches • for refinement • for domain decomposition • Unstructured grid • minimize distance between neighbors in memory • only relationships between neighbors are stored: no traditional array data structure

32. Ocean model versus Atmosphere model Model Hydrostatic Atmosphere Hydrostatic Ocean Equations Vertical coordinate hybrid terrain following z levels Elliptic problem for... a few fast vertical modes, vertical mode decomposition every time step one external mode Commons operators: divergence, vorticity, gradient elliptic solver, time stepping

33. ICON Ocean model • Primitive equation model with a free surface • Discretization of vector-invariant form of momentum equation • Spatial Discretization: C-type staggering • Normal velocity: at triangle edges • Temperature & salinity: at triangle centers • Free surface elevation: at triangle centers • Temporal Discretization: semi-implicit two-timelevel scheme

34. ICON Ocean model Dynamics • 1st version of dynamical core implemented and tested • Physics (work-in-progress) • Forcing • Momentum/heat/fresh-water fluxes (CORE-project) • Bulk formulas • Parametrizations • Vertical mixing, convection • Grid-dependent physics (GM) requires substantial development

35. ICON Ocean model: further development Ocean data assimilation/state estimation using adjoint method • Adjoint model via adjoint compiler • adjoint compiler as integral part of ICON-Ocean model • automatic generation of adjoint code • Strategy • ICON-Ocean development parallel with adjoint development • collaboration with Prof. U. Naumann (RWTH Aachen) • Current status • adjoint ICON-shallow-water model available