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Overview on the COSMO-Model System

Overview on the COSMO-Model System. Ulrich Schättler Deutscher Wetterdienst BU Research and Development Department for Numerical Modelling. Contents. The Model System Development History Components of the COSMO-Model Preprocessing: PEP and INT2LM. The Model System.

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Overview on the COSMO-Model System

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  1. Overview on the COSMO-Model System Ulrich Schättler Deutscher Wetterdienst BU Research and Development Department for Numerical Modelling

  2. Contents The Model System Development History Components of the COSMO-Model Preprocessing: PEP and INT2LM COSMO/CLM Training Course

  3. The Model System The COSMO-Model System is a nonhydrostatic limited-area atmospheric prediction system. It can be used for regional numerical weather prediction (NWP) and regional climate modelling (RCM). The COSMO Community runs the system for daily production of (numerical) weather forecasts. The CLM Community deployed it for the IPCC runs and for various scientific purposes. The software package of the COSMO-Model system is available (freely) for scientific purposes (only!). COSMO/CLM Training Course

  4. COSMO-Model(s) Roshydromet (Moscow, Russia), NMA (Bucharest, Romania): Still in planning / procurement phase DWD (Offenbach, Germany): NEC SX-9 IMGW (Warsawa, Poland): SGI Origin 3800: uses 88 of 100 nodes                          MeteoSwiss: Cray XT4: COSMO-7 and COSMO-2 use 800+4 MPI-Tasks on 402 out of 448 dual core AMD nodes  ARPA-SIM (Bologna, Italy): IBM pwr5: up to 160 of 512 nodes at CINECA COSMO-LEPS (at ECMWF): running on ECMWF pwr5 as member-state time-critical application HNMS (Athens, Greece): IBM pwr4: 120 of 256 nodes USAM (Rome, Italy): HP Linux Cluster XEON biproc quadcore System in preparation ARPA-SIM (Bologna, Italy): Linux-Intel x86-64 Cluster for testing (uses 56 of 120 cores) COSMO/CLM Training Course

  5. CLM Community CLM-Community COSMO/CLM Training Course

  6. The Model System (II) Software / data necessary to run the system: External parameters to describe the earth´s surface: constant data, e.g.: orography, land-sea-mask, soil type (not so constant) data, e.g.: plant characteristics These data can be provided by EXTPAR (DWD) or PEP (CLM) INT2LM: Interpolation program which reads data from a driving model to prepare initial and boundary conditions for the COSMO-Model COSMO-Model: The forecast model itself Postprocessing tools Visualization of results Verification Evalutation of climate runs COSMO/CLM Training Course

  7. The Model System (III) To install the software package for the COSMO-Model on computers, some external libraries are needed: For input and output of data: GRIB Library: GRIB is a standard data format defined by the World Meteorological Organization (WMO) and is widely used by the weather services. NetCDF Library: The Network Common Data Form is a set of software libraries and machine-independent data formats to support the creation, access, and sharing of array-oriented scientific data and is widely used by the climate community. For computing „synthetic satellite images“: RTTOV Library: The Radiative Transfer Model can be used to compute radiances and brightness temperatures, as can be measured by certain satellites and their instruments. COSMO/CLM Training Course

  8. The Model System (IV) The software package for the COSMO-Model contains The source code for the COSMO-Model The source code for the INT2LM The source code for the Grib1 library It does NOT contain (and their use can be avoided) The NetCDF library: It is available from http://www.unidata.ucar.edu (or from the CLM Community) The RTTOV library: This library has been developed in the framework of the NWP-SAF (Satellite Application Facility). For using it, a special licence is necessary, which is available from nwpsaf@metoffice.gov.uk How to avoid using these libraries will be explained in the exercises COSMO/CLM Training Course

  9. History DWD developed the nonhydrostatic Local Model during 1996-1999 and started operational runs on 1 December 1999. The development did not start from the scratch! The former system EM/DM of DWD was used as a basis. In Summer 1999, the Consortium for Small-Scale Modelling was founded by the national weather services of Germany, Switzerland, Italy and Greece, which took over the Local Model Later on, Poland (in 2001) and Romania (in 2007) joined. Russia applied for membership (in 2007). In 2006 it was decided to use COSMO as the common model name COSMO/CLM Training Course

  10. From EM/DM to COSMO EM/DM (now HRM) in the 90ies COSMO-Model (>1999) Basic Framework for NWP Fortran77 Memory Management (with Cray-Extensions) Serial Utilities Framework for NWP and Climate Fortran90 (Standard) Memory Management Parallelization for distributed memory computers Utilities I/O (GRIB 0) I/O (Grib1, NetCDF, Restart) Dynamics (hydrostatic) Dynamics (nonhydrostatic) Assimilation Physics (basic package) Physics (more advanced) Diagnostics Diagnostics Chemics available in a beta-version! COSMO/CLM Training Course

  11. COSMO-Model Components In the following, we will give an overview on the available components some basic explanations (more details will be given during the week for dynamics and physics) some basic namelist variables (for a more detailed listing see the „Tutorial“ and for a complete reference the User Guides for the COSMO-Model and the INT2LM) COSMO/CLM Training Course

  12. Basic Framework The basic organization of the COSMO-Model is done in the main program lmorg.F90. The first task is the setup, to define the configuration (CALL organize_setupin modulesrc_setup.f90) namelist input for the setup definition of the model domain memory management parallelization computation of basic constants and fields The relevant namelist groups are /LMGRID/ /RUNCTL/ COSMO/CLM Training Course

  13. Basic Framework: /LMGRID/ Definition of model domain: COSMO/CLM Training Course

  14. Basic Framework: /RUNCTL/ Initial date and forecast range COSMO/CLM Training Course

  15. Basic Framework: /RUNCTL/ With the following switches you can turn on (.TRUE.) and off (.FALSE.) components: COSMO/CLM Training Course

  16. Basic Framework: /RUNCTL/ Parallel Execution: There are also some „machine-dependent“ variables, like ldatatypes, ncomm_type. For them, all settings should work on any computer, but could give a different performance. NOTE: Only ldatatypes=.TRUE. is NOT working on machines with 64-bit addressing (like the NEC at DWD  ) COSMO/CLM Training Course

  17. Basic Framework: /RUNCTL/ Some other control parameters COSMO/CLM Training Course

  18. Dynamics The COSMO-Model offers two different dynamical cores, the Leapfrog-scheme (old scheme, used since the beginning) and the Runge-Kutta (or 2-timelevel) scheme (implemented in the last years). For both schemes there are several variants. The Runge-Kutta scheme was mainly intended for high-resolution runs (< 3km), but is now also tested for coarser resolutions. We aim to replace the Leapfrog scheme in all applications in the near future. The organization of the schemes and reading of the namelist variables is done in the module organize_dynamics.f90. The relevant namelist group is /DYNCTL/ COSMO/CLM Training Course

  19. Leapfrog HE-VI The „horizontal explicit - vertical implicit“ variant of the Leapfrog scheme is the standard scheme (still) used in coarser resolutions (COSMO-EU). The basic namelist parameters are l2tls=.FALSE. No use of two-time level scheme lsemi_imp=.FALSE. No use of semi-implicit scheme epsass=0.15 filter coefficient for Asselin filter betasw=0.4 time-weighting for VI calculations COSMO/CLM Training Course

  20. Leapfrog Semi-implicit The semi-implicit was implemented to overcome stability problems in small-scale applications, where steep slopes of the orography may occur. Although a larger time step may be used compared to the HE-VI scheme, the necessary solution of an elliptic differential equation made this scheme too expensive for operational use. It is available in the source code, but not tested any more. The basic namelist parameters are l2tls=.FALSE. No use of two-time level scheme lsemi_imp=.TRUE. Use of semi-implicit scheme COSMO/CLM Training Course

  21. Runge-Kutta (2 timelevel) Two variants of a two timelevel Runge-Kutta scheme are implemented: 3rd order scheme after Wicker and Skamarock (default used) „Total Variation Diminishing“ (TVD) variant after Liu, Osher and Chan The basic namelist parameters are l2tls=.TRUE. Use of two-time level scheme irunge_kutta=1/2 Wicker-Skamarock (1) or TVD (2) iadv_order=5 Order of horizontal advection scheme irk_order=3 Order of Runge-Kutta scheme lsl_adv_qx=.TRUE. Switch for Semi-Lagrange advection More parameters can be discussed during the exercises COSMO/CLM Training Course

  22. Physics The COSMO-Model uses several sub-components for the physical parameterizations. For most sub-components, different variants are offered. Note: Not all variants are fully tested! The sub-components are: Microphysics Radiation Moist convection Turbulent diffusion and parameterization of surface fluxes Soil Processes Subgrid Scale Orography Scheme The organization of the schemes and reading of the namelist group /PHYCTL/ is done in the module organize_physics.f90, if lphys=.TRUE. in the setup. COSMO/CLM Training Course

  23. Microphysics Four variants are offered for the microphysics. They mainly differ in the number of cloud and precipitation particles, that are considered. The basic namelist parameters are lgsp=.TRUE. To run microphysics itype_gscp= 1: without ice phases not longer used and tested 2: with snow not longer used and tested 3: with snow and cloud ice used for COSMO-EU 4: with snow, cloud ice, graupel used for COSMO-DE lprogprec=.TRUE. Switch on/off prognostic precipitation For itype_gscp=4, only lprogprec=.TRUE. can be chosen Use of lprogprec=.FALSE. is not tested and therefore not recommended any more! COSMO/CLM Training Course

  24. Radiation The radiation uses the scheme of Ritter and Geleyn, which is based on a delta-two-stream version of the equation for radiative transfer. The basic namelist parameters are lrad=.TRUE. To run the radiation nincrad / hincrad To choose the interval between two calls nradcoarse To run the radiation on a coarser grid =1 original grid >1 nradcoarse grid points are combined in each direction lradf_avg To average the radiative forcing ico2_rad To choose a special CO2 scenario The option, to run on a coarser grid, is just for saving computational time and is used in the COSMO-DE COSMO/CLM Training Course

  25. Convection For applications on the meso-α and meso-β scales down to grid spacings of 5-10 km, cumulus convection is a sub-grid scale process which requires a parameterized representation. Even on the meso-γ scale, a parameterization of shallow convection still is necessary. The basic namelist parameters are lconv=.TRUE. To run the convection parameterization nincconv To choose the interval between two calls itype_conv= 0: Tiedtke scheme (default for COSMO-EU) 1: Kain-Fritsch scheme (is only a test version) 2: Bechtold scheme (not yet available, work going on in Switzerland) 3: Shallow convection (default for COSMO-DE) lconf_avg: To average the convective forcing COSMO/CLM Training Course

  26. Turbulence For the vertical diffusion due to turbulent transport, three schemes are available. The basic namelist parameters are ltur=.TRUE. To run the turbulence scheme itype_turb To choose the special scheme 1: 1-D diagnostic scheme 3: 1-D TKE based diagnostic scheme (default for COSMO-EU, -DE) 5/7: 3-D closure scheme, together with l3dturb=.TRUE. The 1-D diagnostic scheme is the historical scheme from EM/DM and is not used (and tested) any more at DWD. The 3-D closure scheme has been developed lately. It is intended for the kilometer-scale and not yet recommended for use. COSMO/CLM Training Course

  27. Surface Fluxes These fluxes provide a coupling between the atmosphere and the soil model. The basic namelist parameters are ltur=.TRUE. To run the turbulence scheme itype_tran To choose the special scheme 1: for 1-D diagnostic turbulence scheme (not used anymore) 2: for 1-D TKE based diagnostic scheme (default at DWD) The parameterization of surface fluxes for the 1-D TKE based diagnostic scheme is used in all applications by DWD. There are (much) more namelist variables in the turbulence scheme, which should not be changed. They are intended for use by the developers only! COSMO/CLM Training Course

  28. Soil Processes The calculation of surface fluxes requires the knowledge of the temperature and the specific humidity at the ground. The COSMO-Model offers two variants of a soil model. The basic namelist parameters are lsoil=.TRUE. To run the soil model lmulti_layer To choose the special scheme =.TRUE. To run a multi-layer (deep soil) scheme (default) =.FALSE. To run the historic 2-(3-) layer scheme. llake To run the FLake model The FLake-Model has been implemented recently. At the moment it cannot be used extensively, because it requires additional external parameters, that cannot be provided routinely up to now. COSMO/CLM Training Course

  29. Subgrid Scale Orography The subgrid scale orography scheme deals explicitely with a low-level flow, which is blocked, if the subgrid scale orography is sufficiently high. The basic namelist parameters are lsso=.TRUE. To run the subgrid scale orography scheme nincsso To run the scheme only every nincsso timesteps COSMO/CLM Training Course

  30. Input / Output For practical simulations, it is necessary to get data into and out of the model. For idealized test cases, input can be switched off. The COSMO-Model supports three different data formats: Grib, Version 1 NetCDF Binary data (only for Restarts) It is planned to implement Grib, Version 2, „in the near future“ (may take 1-2 years!) It would be better to have the restart files in NetCDF, to be machine independent. The organization of I/O and reading of the 3 namelist groups is done in the module organize_data.f90. COSMO/CLM Training Course

  31. Input / Output: /IOCTL/ This group defines the most important parameters for I/O COSMO/CLM Training Course

  32. Input / Output: /GRIBIN/ This group defines parameters for input (not only GRIB!) COSMO/CLM Training Course

  33. Input / Output: /GRIBOUT/ This group defines parameters for output (not only GRIB!) This group can occur several times, to specify different kind of output for different model times. COSMO/CLM Training Course

  34. Preprocessing To run the COSMO-Model, several fields have to be provided (Note: Some of them are depending on Namelist switches) External parameters: Constant or slowly varying fields for : HSURF (FIS), FR_LAND, SOILTYP, Z0, FR_LAKE, DEPTH_LK, FOR_E, FOR_D, constant PLCOV, LAI, ROOTDP, annual cycle VIO3, HMO3 annual cycle Initial fields: Atmosphere: U, V, W, T, PP, QV, QC, QI, QR, QS, QG Soil and surface: T_SNOW, W_SNOW, W_I, QV_S, T_S, T_SO, W_SO, FRESHSNW, RHO_SNOW, (T_M, T_CL, WG_1, WG_2, W_CL) Boundary fields: Atmosphere: U, V, W, T, PP, QV, QC, QI, QR, QS, QG Soil and surface: T_SNOW, W_SNOW, QV_S, (T_S, T_M, WG_1, WG_2) COSMO/CLM Training Course

  35. Preprocessing: EXTPAR / PEP The external parameters have to be provided for a special application (domain, grid size and resolution) of the COSMO-Model. They are derived from (global / regional) raw data sets like GTOPO30, GLC2000, etc. DWD developed a program, to process these data some time ago (EXTPAR) The CLM Community (mainly: Gerhard Smiatek from Garmisch), extended this program (e.g. processing of ECOCLIMAP data; writing of files in NetCDF (?)) Outcome is the program for PEP: Preparing External Parameters COSMO/CLM Training Course

  36. Preprocessing: PEP (II) PEP is NOT distributed with the COSMO-Model package! Because without the raw data it does not make sense. And the raw data are several hundreds of GBytes! If you need a special set of external parameters, you can contact DWD (but we are not running PEP, only the original part) contact M&D in Hamburg: they installed the PEP together with the raw data) DWD started to modernize and harmonize its own program. Later on, a web-interface will be implemented, over which external parameter data sets can be ordered. COSMO/CLM Training Course

  37. Preprocessing: INT2LM The INT2LM does the final preprocessing of all input data for the COSMO-Model. Despite the name, this is more than just an interpolation. The constant external parameters are taken as provided by EXTPAR / PEP. The varying external parameters are taken from EXTPAR/ PEP and processed for the special day of the year. The variables for ozone (vio3, hmo3) are not provided by EXTPAR / PEP, but are computed by INT2LM, depending on the special day of the year. COSMO/CLM Training Course

  38. Preprocessing: INT2LM (II) All other initial and boundary fields are taken from a coarse grid model and processed for the COSMO-Model domain. This involves (mainly) a horizontal interpolation, a vertical interpolation and a special treatment in the boundary layer. Running the INT2LM is controlled by several Namelist groups. COSMO/CLM Training Course

  39. INT2LM: /CONTRL/ Basic control: COSMO/CLM Training Course

  40. INT2LM: /GRID_IN/ This group specifies the characteristics of the input model: COSMO/CLM Training Course

  41. INT2LM: /LMGRID/ Definition of model domain (same as in the COSMO-Model): COSMO/CLM Training Course

  42. INT2LM: /DATA/ This group controls the input and output: COSMO/CLM Training Course

  43. Coming to an END This presentation should have given you an overview on the different parts and components of the COSMO-Model System. During this week you will learn more on the theoretical aspects for the dynamics, physics and additional components. You will also get some practical experience for installing the source code and running the necessary programs during the „Tutorials“. We are happy to take your comments and suggestions! COSMO/CLM Training Course

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