Sudden Stratospheric Warmings and the Brewer-Dobson Circulation: diagnostics and interactions
The polar winter stratosphere is dominated by strong thermally-driven westerly winds (Andrews et al. 1987). Every two years on average (Charlton and Polvani 2007), this polar vortex is disrupted by a Sudden Stratospheric Warming (SSW), whereby the polar stratosphere warms rapidly (McInturff 1978). S...
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| Tipo de recurso: | tesis doctoral |
| Fecha de publicación: | 2018 |
| País: | España |
| Institución: | Universidad Complutense de Madrid (UCM) |
| Repositorio: | Docta Complutense |
| Idioma: | inglés |
| OAI Identifier: | oai:docta.ucm.es:20.500.14352/16496 |
| Acceso en línea: | https://hdl.handle.net/20.500.14352/16496 |
| Access Level: | acceso abierto |
| Palabra clave: | 551.513(043.2) Atmospheric Circulation Brewer-Dobson Circulation Sudden Stratospheric Warming Polar winter stratosphere Dinámica atmosférica Circulación de Brewer-Dobson Calentamiento súbito estratosférico Estratosfera polar Meteorología (Física) |
| Sumario: | The polar winter stratosphere is dominated by strong thermally-driven westerly winds (Andrews et al. 1987). Every two years on average (Charlton and Polvani 2007), this polar vortex is disrupted by a Sudden Stratospheric Warming (SSW), whereby the polar stratosphere warms rapidly (McInturff 1978). SSWs are related with enhanced planetary wave (PW) activity reaching the polar stratosphere and depositing momentum to the zonal mean flow (Matsuno 1971). Also wave-driven, the Brewer-Dobson Circulation (BDC) is responsible for the equator-to-pole mass transport (e.g., Andrews et al. 1987), specially its deep branch, in the middle and upper stratosphere (Plumb 2002). SSWs and BDC are the most illustrative examples of the polar stratospheric variability. However, there are still open questions regarding their underlying processes, mutual interactions and the expected trends under climate change scenarios. Some of them are explored in this thesis. Objectives: 1. To assess the discrepancies in SSW frequencies and signatures across different SSW definitions. 2. To understand how new model developments, and in particular the Turbulent Mountain Stress (TMS) parameterization influences SSW occurrence. 3. To explore the relationship between SSWs and the polar downwelling of the deep branch of the BDC. 4. To investigate the driving processes of the BDC and its future trends under climate change scenarios... |
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