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| Titel |
Convergence properties of the spatial schemes in the COSMO model and requirements on higher order spatial convergence |
| VerfasserIn |
Andreas Will, Jack Ogaja |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250058111
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| Zusammenfassung |
| Wicker and Skamarock (2002) suggested higher order spatial schemes for
the advection term of the WRF model. The convergence properties have
been demonstrated by a one-dimensional advection test. These schemes
(2nd, 4th and 6h central differences and 3rd and 5th upwind) have been
also implemented in the non-hydrostatic COSMO model.
We analysed the convergence properties of the schemes in the COSMO
model investigating the 2D stationary mountain flow idealized test
case. The main assumptions of this test case are stationarity and a
z-dependent basic flow with a zero vertical velocity ( i.e. w0 = 0).
A systematic series of simulations was conducted for the RK dynamical
core. The configuration was chosen in such a way, that other error
sources like test assumptions, discretisation in time and vertical
discretisation were sufficiently small. The domain size of the
idealized test case was 500x30(20) km2. The classical error norms have
been calculated and the characteristics of the convergence have been
investigated (amplitude and phase error, order of accuracy).
The results exhibit an order of convergence much smaller than the
theoretical values for all horizontal schemes available. This exhibits
the need for adequate testing of the numerical properties of the
models.
The series of simulations has been repeated for an improved
discretisation of the advection operator where the interpolation and
the discretisation truncation error were chosen the same. The results
will be discussed. |
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