1 / 16

Michael Baldauf Deutscher Wetterdienst, Offenbach, Germany

Priority Project "Conservative Dynamical Core" Final report COSMO General Meeting 10-13 Sept. 2012, Lugano. Michael Baldauf Deutscher Wetterdienst, Offenbach, Germany. from project proposal: April 2008. Motivation: The current COSMO dynamical core does not possess any conservation

hop
Download Presentation

Michael Baldauf Deutscher Wetterdienst, Offenbach, Germany

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Priority Project "Conservative Dynamical Core" Final report COSMO General Meeting 10-13 Sept. 2012, Lugano Michael Baldauf Deutscher Wetterdienst, Offenbach, Germany M. Baldauf (DWD)

  2. from project proposal: April 2008 Motivation: The current COSMO dynamical core does not possess any conservation properties! project : 'Conservative dynamical core' • Conservation of • mass (total and tracer) • energy • momentum • Strategical advantages: • general trend in atmospheric modeling • collaboration with CLM ('climate COSMO')hint: 'regional ICON'-climate modelling could be competivie to CLM • collaboration with COSMO-ART (chemical/aerosol modeling) M. Baldauf (DWD)

  3. from project proposal: April 2008 • Methodology: Finite-Volume-Methods (applied to equations in conservation form) • well established in CFD • become increasing meaning in atmospheric modeling • Advantages: • conserves the prognostic variable • big flexibility • positive definite, if desired (by flux limitation) • can handle steep gradients in the solution (e.g. by flux correction) (even shocks and other discontinuities, though they are not so important in atmosphere) • advantages in steep orography (?)  implicit solver important • (applicable on arbitrary unstructured grids)in this project, structured grid is plannedfar range plans could use unstructured grid, e.g. for a more efficient implementation of a z-coordinate version M. Baldauf (DWD)

  4. Whyconservationcanbeimportant … thelessobviousaspect Example: 1-dim. Shallowwaterequations, Dam break problem expansionof a shock (totheright) and a rarefactionwave (totheleft) Initial statefor H and u: Solution methods: Exact Riemann-solver(Godunov method) Simple FD-schemecent. Diff. 2nd order Simple FV-scheme: fluxescalc.withcent. Diff. 2nd ordertime integrationwith RK 4. order as 3.: but withartificialdiffusion H u

  5. Riemann-solver FD; cent. Diff. +diffusion H H u H u FV; cent. Diff.;+ diffusion FV; cent. Diff.; H H H u H u

  6. Riemann-solver FD; cent. Diff. +diffusion FV; cent. Diff.;+ diffusion FV; cent. Diff.;

  7. FD; cent. Diff. +diffusion ‚Exact‘ Riemann-solver FV; cent. Diff.;+ diffusion FV; cent. Diff.;

  8. Riemann-solver FV-scheme (equations in conservation form) FD-scheme (equations in advection form) Wrong position of the shock front M. Baldauf (DWD)

  9. from project proposal: April 2008 • Issue: steep orography • Motivation: COSMO with 1 km resosution (MeteoCH, PP CORSO, …) • What are the limitations of the terrain-following coordinate? • How can these limits be shifted towards steeper orography? • Issue: Advection of scalars (Moisture variables, TKE, …) • full 3D (non-splitted) schemethe problems with splitted schemes could be seen during the development of the Bott-scheme (Task 4 of PP RK) • robustnesscurrently the (non-conserving) Semi-Lagrange-scheme is more robust than Bott • mass-consistency:should the advection scheme for scalars be the same than that for  ? M. Baldauf (DWD)

  10. Solutions came up soon ... • Implicit Finite-Volume solver CONSOL'borrowed' from aeronautics(proposal by Pier Luigi Vitagliano, CIRA)transfer to meteorological applications is quite innovative compressible branch • EULAG model(proposal by Michal Ziemianski, IMGW) there exist a quite large community that uses the EULAG model EULAG (anelastic) branch • (further ideas (finite volume form of current RK, ...) were stopped by STC) M. Baldauf (DWD)

  11. Whathappeneduntilnow … April 2008 proposalofnew PP CDC in the SMC Sept 2008 proposalofnew PP CDC presented at GM in Krakow = officialstartoftheproject June 2009 Kick off meetingorganizedby IMGW in Wirzba/Poland 2009 EULAG: Idealized (colddensitycurrent, risingthermals, inertia-gravitywaves, mountainflows) andfirst semi-realistictests (COSMO 2.2 km overthe Alps) CONSOL: implementationofbuoyancyprocessesandidealizedtestswithmountainflow 2010 definitionofthedecisiontree EULAG: finalizeidealizedtests, more semi-realisticsimulations June 2010 SMC evaluationmeeting in Sopot  continuation 2011 startoftheimplementationof EULAG dyn. coreinto COSMO MPDATA in COSMO; comparisontowards Semi-Lagr., Bott 2012 testingof COSMO-EULAG with all idealizedand quasi-realistictests July 2012 common CDC/POMPA meeting, statusof CDC; follow-up PP M. Baldauf (DWD)

  12. Management issues FTE's used + ~0.2 FTE's/year for project leadership = 0.8 FTE in total M. Baldauf (DWD)

  13. Whatdidweget (I) • EULAG-branch: • welearnedquite a lotabouttheanelasticapproximations • wegot a soundfeelingaboutprincipalpropertiesofthe EULAG dynamicalcore • a newdynamicalcoreisavailable in COSMO as a prototype • split-explicit, HE-VI (Runge-Kutta, leapfrog): finite difference, compressible • semi-implicit: finite difference, compressible • COSMO-EULAG: finite volume, anelasticconservationofmomentum, tracermassflux form eq. forinternalenergyabilityto handle steepslopes • Almost all itemsofthe „EULAG branch“ (=task1) andmostofthedecisiontreewerefulfilled M. Baldauf (DWD)

  14. What did we get (II) • compressiblebranch • welearned a lotaboutimplicit Finite-Volume solver • Toy model CONSOL formeteorologicaltestsavailable • dual time steppingas an alternative time-integration (?) • MPDATA as a possible alternative traceradvectionalgorithmisavailable(not yet in theofficialversion) M. Baldauf (DWD)

  15. What did we get (III) : Publications M. Z. Ziemiański, M. J. Kurowski, Z. P. Piotrowski, B. Rosa and O. Fuhrer: Toward very high resolution NWP over Alps: Influence of the increasing model resolution on the flow pattern, Acta Geophysica 59 (6), 2011, 1205-1235 B. Rosa, M. J. Kurowski, and M. Z. Ziemiański: Testing the anelasticnonhydrostatic model EULAG as aprospective dynamical core of a numericalweather prediction model. Part I: Dry Benchmarks, Acta Geophysica 59 (6), 2011, 1235-1266 M. J. Kurowski, B. Rosa and M. Z. Ziemiański: Testing the anelasticnonhydrostatic model EULAG as a prospective dynamical core of numerical weather prediction model. Part II: Simulations of a supercell, Acta Geophysica 59 (6), 2011, 1267-1293 M. Baldauf: Non-hydrostatic modelling with the COSMO model,Proceedings of ‘ECMWF workshop on non-hydrostatic modelling’, ECMWF, 2010, p. 161-169(compare dispersion relation of compressible eqns. with divergence damping and anelastic approximation) M. Baldauf (DWD)

  16. What next? The 'compressible branch' CONSOL will (hopefully) be continued in WG2 The 'EULAG-branch' will (probably) be continued in a follow-up project"COSMO-EULAG operationalization (CELO)" project leader: Zbigniew Piotrowski (IMGW) Many thanks to the CDC development team (in alphabetical order): Oliver Fuhrer, Marcin Kurowski, Guy de Morsier, Marie Müllner, Zbigniew Piotrovski,Bogdan Rosa, Pier Luigi Vitagliano, Damian Wojcik, Michal Ziemianski M. Baldauf (DWD)

More Related