Inherently mass-conservative version of the semi-Lagrangian absolute vorticity (SL-AV) atmospheric model dynamical core
The semi-Lagrangian absolute vorticity (SL-AV) atmospheric model is the global semi-Lagrangian hydrostatic model used for operational medium-range and seasonal forecasts at the Hydrometeorological Centre of Russia. The distinct feature of the SL-AV dynamical core is the semi-implicit, semi-Lagrangia...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2014-02-01
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| Series: | Geoscientific Model Development |
| Online Access: | http://www.geosci-model-dev.net/7/407/2014/gmd-7-407-2014.pdf |
| Summary: | The semi-Lagrangian absolute vorticity (SL-AV) atmospheric model is the
global semi-Lagrangian hydrostatic model used for operational medium-range
and seasonal forecasts at the Hydrometeorological Centre of Russia. The distinct
feature of the SL-AV dynamical core is the semi-implicit, semi-Lagrangian
vorticity-divergence formulation on the unstaggered grid. A semi-implicit,
semi-Lagrangian approach allows for long time steps but violates the global
and local mass conservation. In particular, the total mass in simulations
with semi-Lagrangian models can drift significantly if no a posteriori
mass-fixing algorithm is applied. However, the global mass-fixing
algorithms degrade the local mass conservation.
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The new inherently mass-conservative version of the SL-AV model dynamical core
presented here ensures global and local mass conservation without
mass-fixing algorithms. The mass conservation is achieved with the
introduction of the finite-volume, semi-Lagrangian discretization for a
continuity equation based on the 3-D extension of the conservative cascade
semi-Lagrangian transport scheme (CCS). Numerical experiments show that
the new version of the SL-AV dynamical core presented combines the accuracy and
stability of the standard SL-AV dynamical core with the mass-conservation
properties. The results of the mountain-induced Rossby-wave test and
baroclinic instability test for the mass-conservative dynamical core are found to
be in agreement with the results available in the literature. |
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| ISSN: | 1991-959X 1991-9603 |