Counterpropagating Rossby waves and barotropic instability
A novel attempt is made to quantify the qualitative interpretation of barotropic instability in terms of counterpropagating Rosssby waves (CRW) as proposed by Hoskins et al. (1985). Although many investigations have been devoted to this quantification in the past, a minimum resolution grid point mod...
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| Format: | Article |
| Language: | English |
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Borntraeger
2007-10-01
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| Series: | Meteorologische Zeitschrift |
| Online Access: | http://dx.doi.org/10.1127/0941-2948/2007/0239 |
| Summary: | A novel attempt is made to quantify the qualitative interpretation of barotropic instability in terms of counterpropagating Rosssby waves (CRW) as proposed by Hoskins et al. (1985). Although many investigations have been devoted to this quantification in the past, a minimum resolution grid point model is chosen here as a tool where complete insight can be achieved with little effort. Barotropic instability is discussed in terms of standard gridpoint modes and also of vorticity modes which are the analogue of the CRWs. The intercomparison of both approaches leads to a fresh look at the mechanism of barotropic instability. It is pointed out that CRWs cannot be defined in a corresponding low-order spectral model although this model is quite successful in capturing the main features of barotropic instability. It is concluded that CRWs are mathematical structures which are helpful but not essential for an understanding of barotropic instability. |
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| ISSN: | 0941-2948 |