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Excitation and dispersion of a Rossby wave train on the polar jet by an extra-tropical transition of a hurricane

The enhanced potential vorticity gradients along the polar jet serve as a wave guide for trapped Rossby waves. These tropopause level, synoptic scale Rossby waves are of primary importance for weather development at the surface. In particular, extreme weather events have been linked to the existence of overlying upper level meridionally elongated filaments of stratospheric (high potential vorticity) air which form during the breaking of these waves. Motivated by the desire to understand the conditions under which these waves are formed and to improve their predictability, the current thesis discusses one excitation mechanism---the potential vorticity anomaly associated with a hurricane approaching the extra-tropics. / Attention is directed toward the adiabatic interaction of the cyclone with the polar jet before the two features meet. The hurricane's ability to excite Rossby waves is verified from observations of past interactions and theoretical study using a mechanistic model with idealized settings. The nature of the interaction between the cyclone and the polar jet is found to be sensitive to parameters such as the cyclone's radius and PV anomaly. Three different regimes have been identified. It is also concluded that the same parameters have influence on the skill of the Rossby wave prediction. The more intense the cyclone is, the harder it is to accurately predict the response of the polar jet.

Identiferoai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.101167
Date January 2006
CreatorsRavia, Roni.
PublisherMcGill University
Source SetsLibrary and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada
LanguageEnglish
Detected LanguageEnglish
TypeElectronic Thesis or Dissertation
Formatapplication/pdf
CoverageMaster of Science (Department of Atmospheric and Oceanic Sciences.)
Rights© Roni Ravia, 2006
Relationalephsysno: 002598446, proquestno: AAIMR32776, Theses scanned by UMI/ProQuest.

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