The driving of baroclinic anomalies at different timescales
This work investigates the internal variability of zonal-mean baroclinicity over the Southern Hemisphere midlatitudes. The first two leading modes describe a meridional baroclinicity shift and a sharpening/broadening of baroclinicity, with the shift becoming more dominant at low frequency. The lifec...
| Autores: | , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2011 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/61222 |
| Acceso en línea: | http://hdl.handle.net/10261/61222 |
| Access Level: | acceso abierto |
| Palabra clave: | Atmospheric processes Climate change Annular mode baroclinicity variability extratropical dynamics zonal index |
| Sumario: | This work investigates the internal variability of zonal-mean baroclinicity over the Southern Hemisphere midlatitudes. The first two leading modes describe a meridional baroclinicity shift and a sharpening/broadening of baroclinicity, with the shift becoming more dominant at low frequency. The lifecycles of the baroclinic anomalies, estimated by means of lagged regression analysis, are qualitatively different depending on the frequency range. At high frequency, the zonal-mean baroclinicity simply responds to the fast eddy heat flux forcing. At low frequency, the baroclinicity shift is forced by the eddy momentum flux through an eddy driven mean meridional circulation and damped diabatically. The meridional eddy heat flux by planetary scale eddies also contributes to the low-frequency shift but the synoptic eddy heat flux behaves diffusively and damps the baroclinicity anomalies at low frequency. |
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