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Filtered non‐hydrostatic models in pressure‐related coordinates
Author(s) -
Rõõm Rein,
Miranda Pedro M. A.,
Thorpe Alan J.
Publication year - 2001
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1002/qj.49712757408
Subject(s) - hydrostatic equilibrium , adiabatic process , hydrostatic pressure , sigma , mechanics , stability (learning theory) , coordinate system , physics , classical mechanics , computer science , mathematics , geometry , thermodynamics , quantum mechanics , machine learning
The anelastic sigma‐coordinate version of the pseudo‐anelastic Miller‐Pearce model is developed. The pseudo‐anelastic model is characterized by the presence of external‐mode acoustic perturbations which propagate in the horizontal, compromising the model performance by the need to use smaller time steps than would otherwise be required. The approach developed in this study allows for the filtering of acoustic waves and adjustment of surface pressure perturbations. The approach is tested in a new numerical implementation of an adiabatic sigma‐coordinate non‐hydrostatic model and results are found to be comparable to the unadjusted version, and to theory when applicable. The new code is found to allow for significantly larger time steps whilst still retaining numerical stability, showing the possibility of further model improvements.