Hybridization between σ- and z-co-ordinates for improving the internal pressure gradient calculation in marine models with steep bottom slopes
✍ Scribed by Hans Burchard; Ole Petersen; Ole Petersen
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 353 KB
- Volume
- 25
- Category
- Article
- ISSN
- 0271-2091
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✦ Synopsis
It is discussed in this paper how the pressure gradient error in general vertical co-ordinate models (in which the s-transformation is a special case) can be reduced by means of hybrid models. For a better understanding, the derivation of such a general vertical co-ordinate model from the Cartesian co-ordinate model is given. Two types of hybridization between s-and z-co-ordinate models, each using one parameter specifying the degree of hydridization, are presented: (i) the mixed layer transformation with a constant number of layers which are re®ned near the surface and (ii) the zas-transformation which introduces steps near the bottom. In order to achieve good results with the models using other than s-co-ordinates, a pro®le-conserving momentum advection discretization is developed. The different co-ordinate transformations are tested with 2D barotropic and baroclinic ¯ows over a topographic bump. Those models with nearly horizontal co-ordinate surfaces in the strati®ed area give the best correspondence with an isopycnal reference solution.