ICON Bucharest 2006

J.Steppeler, Ripodas, Th. Heinze, D. Majewski (DWD - German Weather Service, Offenbach, Germany)

L. Bonaventura (MOX - Politecnico di Milano, Italy)

M. A. Giorgetta (Max Planck Institute for Meteorology, Hamburg, Germany)

Intro: Goals of the ICON project

• New unified weather forecasting (DWD) and climate model (MPI-M).• Mass conservation +

discr. continuity eq. = discr. transport eq. with c≡1 • Quasi uniform horizontal resolution

icosahedral grids• Local grid refinement in one or more regions

triangular cells• Global or regional domain• Hydrostatic, and non-hydrostatic• Ocean GCM using same grid and data structures and numerical

operators

Intro: Main participants

DWD: Deutscher Wetterdienst, Germany

D. Majewski, Th. Heinze, P. Ripodas, B. Ritter, H. Frank, D. Liermann,

U. Schättler, J. Steppeler

MPI-M: Max-Planck-Institute for Meteorology, Germany

E. Roeckner, M. Giorgetta, L. Kornblueh, U. Schulzweida, P. Korn, H.Wan

MOX – Politecnico di Milano, Italy

L. Bonaventura

Others: W. Sawyer (ETH Zürich), P. Sanders (Uni Karlsruhe), D. Steurer

(MPI-I, Saarbrücken), J. Baudisch (TU München)

Discussions and/or joint work:

R. Klein, F.X. Giraldo, J. Klemp, D. Randall, T. Ringler, H. Tomita

ICON main line• Grid structure based on Thuburn (1997) +

optimization option (Heikes and Randall, 1995)

• 2 conservation variants:– Mass and potential vorticity conservative scheme – Mass and energy conserving scheme

• 2 or 3 time level semi-implicit time stepping

ICON side line

• Grid structure based on great circle grids• Uniform third order approximation• Easy incorporation of ordinary grid conceps and existing local models

GME: 3 time level

ICOSWP: 2 time level

Local zooming option: grid generation

> Lat-Lon region > Circular region

> 3 refinement leves > 3 refinement levels

NP=3 NP=4 NP=5

Cube 4-body Isocahedron

Rhomboidal divisions of the sphere

• Four points r1,r2,r3,r4 may have any position in space

• Divide the sides of the rhomboid equally and connect opposite points

• Bilinear grid theorem: each coordinate line intersects each line of the crossing coordinate line family. The grid is regular in each direction.

Bilinear grids

Third order convergence of shallow water model at day 3

Third order convergence of shallow water model at day 3

END