Universität Hamburg

Meteorologisches Institut

Universität Hamburg

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The Shallow Atmosphere Model (SAM) is based on the shallow water equations. SAM forms together with PUMA and the Planet Simulator a hierarchy of spectral global atmospheric models which are in use at  the Meteorological Institute of the University Hamburg. It represents the simplest model in this hierarchy. SAM  simulates the barotropic (vertically averaged) flow of the atmosphere while the effect of  non-barotropic (baroclinic) processes must be parameterized in the model. However, the first weather forecast models were indeed barotropic models like SAM and it is possible to simulate the time evolution of the synoptic-scale barotropic flow surprisingly well with such a model.

SAM should be adopted to study planetary circulation phenomena which are essentially two-dimensional. Planetary stationary and low frequency circulation pattern for example have a rather barotropic structure and their dynamics could be investigated with SAM. Another important issue for SAM is the simulation of geostrophic turbulence. Since the model has only a single layer it is possible to run the model at very high spectral resolutions that are necessary to properly describe the cascade to small scales. SAM  is not limited to the terrestrial regime. It can, for example, be used for a better understanding of cloud band structures on Jupiter.

Like PUMA, SAM is a spectral numerical model. The SAM code is written in Fortran90 and it is portable. SAM is  compatible with the graphical user interface and the postprocessing program pumaburner.