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The dynamics of cut-off lows and their vertical extension to the surface
Thesis (PhD (Meteorology))--Universty of Pretoria, 2021.
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| Format: | Thesis |
| Language: | English |
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University of Pretoria
2021
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| _version_ | 1867613670624722944 |
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| access_status_str | Open Access |
| author2 | Ndarana, Thando |
| author_browse | Ndarana, Thando |
| author_facet | Ndarana, Thando |
| collection | Thesis |
| dc_rights_str_mv | © 2019 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Thesis (PhD (Meteorology))--Universty of Pretoria, 2021. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/80842 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:39:50.639Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2021 |
| publishDateRange | 2021 |
| publishDateSort | 2021 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/80842 The dynamics of cut-off lows and their vertical extension to the surface Ndarana, Thando weathermanbarnes@gmail.com Landman, Willem Adolf Barnes, Michael A. UCTD Meteorology Thesis (PhD (Meteorology))--Universty of Pretoria, 2021. Cut-off low (COL) pressure systems are critical weather systems which can result in resulting various severe weather events on South Africa. COLs are often associated with surface cyclones which can enhance weather-related impacts on affected communities. This is shown by a case study of Cape Storm, a COL extension associated with explosive cyclogenesis that had dire effects on the Western Cape of South Africa. The stratospheric effects that determine a COLs extension to the surface and eventual impact on South Africa are studied from a potential vorticity (PV) perspective in terms of a case study, a climatology and an idealised framework. Deep COLs (which extend to the surface) are most frequent in the autumn months, are longer lasting, are more mobile and found most frequently in the higher latitudes. Stratospheric, high-PV intrusions that are associated with COLs are studied in detail with respect to a COLs extension. PV intrusions which extend closer to the surface more frequently result in surface cyclogenesis. This is independent on the size (or intensity) of the intrusion as PV intrusions which extend from higher tropopause heights tend to result in shallow COL development. COLs, have in the past, been viewed as upper-level systems that systematically extend to the surface. Composite analysis however shows that deep COLs associated with deep PV intrusions result in the simultaneous amplification of troughs throughout the troposphere, with the surface cyclone developing within a day of the COL. Geography, Geoinformatics and Meteorology PhD (Meteorology) Restricted 2021-07-15T08:24:54Z 2021-07-15T08:24:54Z 2021 2021 Thesis Barnes, MA 2021, The dynamics of cut-off lows and their vertical extension to the surface, PhD (Meteorology) Thesis, University of Pretoria, Pretoria, viewed yymmdd <http://hdl.handle.net/2263/80842> S2021 http://hdl.handle.net/2263/80842 en © 2019 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria |
| spellingShingle | UCTD Meteorology The dynamics of cut-off lows and their vertical extension to the surface |
| title | The dynamics of cut-off lows and their vertical extension to the surface |
| title_full | The dynamics of cut-off lows and their vertical extension to the surface |
| title_fullStr | The dynamics of cut-off lows and their vertical extension to the surface |
| title_full_unstemmed | The dynamics of cut-off lows and their vertical extension to the surface |
| title_short | The dynamics of cut-off lows and their vertical extension to the surface |
| title_sort | dynamics of cut off lows and their vertical extension to the surface |
| topic | UCTD Meteorology |
| url | http://hdl.handle.net/2263/80842 |