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Title: Hurricane Formation and Modification in the south-eastern Caribbean
Author: Georgiadis, Alexandros
ISNI:       0000 0001 3494 8201
Awarding Body: University of Sheffield
Current Institution: University of Sheffield
Date of Award: 2007
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The south-east sector of the Caribbean (core area) exhibits a distinct suppression in cyclogenesis that contrasts sharply with the hurricane climatology of the neighbouring subbasins. Multivariate statistical analysis (Principal Component Analysis) of the basic environmental variables extracted from the ERA-40 reanalysis dataset near the surface and the tropopause reveals three climatologically different regions within the North Atlantic: (i) one located in the south-west Caribbean, (ii) another characteristic for the rest of the Caribbean, and the last (iii) dominating the Atlantic eastwards of the Less<;;r Antilles. Although the thermodynamics are typically conducive for cyclogenesis throughout the analysis area, the major difference between the climatologies of the Caribbean and the Atlantic is due to the effective thermodynamic background, which appears to be less favourable over the Atlantic. The south-west Caribbean, corresponding to the north-most position of the rising limb ofthe Walker circulation over the Americas, is the most favourable of the three climatic 'regimes', characterised by cyclonic relative vorticity and exceptionally low vertical wind shear, while within the eastern Caribbean, (and the Atlantic) these features are reversed. Furthermore, the spatial variation of the mean low-level circulation over the Caribbean leads to a quadrapole pattern across the region where the climatological background of the northern part of the core area is the least favourable for cyclone formation, combining negative relative vorticity with background divergence. Comparative analysis of composites extracted during cyclogenesis/cyclolisis events revealed that the combination of the environmental conditions in the two sub-sectors (south and north) of the western Caribbean renders the whole region conducive to enhanced hurricane formation. On average, the easterlies reach their maximum intensity approximately around IS
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available