Validation of a mesoscale weather prediction model using subdomain budgets

Article English OPEN
Petrik, Ronny ; Baldauf, Michael ; Schlünzen, Heinke ; Gassmann, Almut (2011)

The monitoring of conservation properties is essential for model development and for the investigation of the hydrological cycle. This is especially relevant for models that do not solve equations in flux form and do not apply a finite volume discretization. The conservation properties of the mesoscale model COSMO are evaluated by using a finite volume diagnostic approach. That is the subdomain budget of energy, water mass and total mass are diagnosed in a control volume that can be placed at each site in the model domain and is independent of the grid size. Thus, this diagnostic method has the major advantage that it can be applied to realistic simulations. The application of the diagnostic method to the COSMO model reveals a good preservation of the water mass, but large errors in energy and total mass conservation. The analysis shows to which extent errors in the treatment of thermodynamical processes, numerical filters and moisture advection schemes contaminate the subdomain budgets. In this paper we will show that the application of a saturation adjustment scheme under a fixed volume condition is required for models, which use the non-hydrostatic equations and height-based coordinates. Also, a further extension of the model physics will be introduced and discussed for a realistic test case.
  • References (28)
    28 references, page 1 of 3

    Baldauf, M. 2008. A tool for testing conservation properties in the COSMO-model, COSMO Newsletter No. 7, Deutscher Wetterdienst, Offenbach a. M., Germany.

    Bott, A. 1989. A positive definite advection scheme obtained by nonlinear renormalization of the advective fluxes. Mon. Wea. Rev. 117, 1006-1015.

    Bryan, G. H. and Fritsch, J. M. 2002. A benchmark simulation for moist nonhydrostatic numerical models. Mon. Wea. Rev. 130, 2917-2928.

    Catry, B., Geleyn, J.-F., Tudor, M., Be´nard, P. and Troja´kova, A. 2007. Flux-conservative thermodynamic equations in a mass-weighted framework. Tellus 59A, 71-79.

    Doms, G. 2004. Test of the moisture mass conservation in LM, COSMO Newsletter No. 3, Deutscher Wetterdienst, Offenbach a. M., Germany.

    Doms, G. and Schaettler, U. 2002. A description of the nonhydrostatic Regional Model LM - part I: dynamics and numerics, DWD Documentation, Deutscher Wetterdienst, Offenbach a. M., Germany.

    Doms, G., Foerstner, J., Heise, E., Herzog, H.-J., Raschendorfer, M. and co-authors. 2002. A description of the nonhydrostatic Regional Model LM - part II: physical parametrization, DWD Documentation, Deutscher Wetterdienst, Offenbach a. M., Germany.

    Doswell, C. A. and Rasmussen, E. N. 1994. The effect of neglecting the virtual temperature correction on cape calculation. Wea. Forecast. 9, 625-629.

    Dudhia, J. 1993. A nonhydrostatic version of the penn state-ncar mesoscale model: validation tests and simulation of an atlantic cyclone and cold front. Mon. Wea. Rev. 121, 1493-1513.

    Durran, D. R. 1999. Numerical methods for wave equations in geophysical fluid dynamics. In: Texts in Applied Mathematics, 1st Edition. (ed. Durran, D. R.). Springer-Verlag, New York, USA.

  • Metrics
    No metrics available
Share - Bookmark