Document Details
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Document Type |
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Article In Journal |
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Document Title |
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On the relationship between Potential Vorticity and Cyclogenesis العلاقة بين الدردورية الجهدية وتكون وتطور المنخفضات |
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Document Language |
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English |
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Abstract |
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Cyclones and anticyclones are the dominant synoptic scale meteorological weather systems in midlatitudes. An attractive way to study dynamical aspects of these structures is provided by the use of potential vorticity (PV) framework. In this paper several aspects of midlatitude cyclogenesis are investigated within this PV framework using a case study analyses. The analysis of absolute, relative and potential vorticity imply the significance of the upper level dynamics in the initiation of this case of cyclogenesis. On one hand, the isobaric vorticity analysis appears to be an informative, accurate and easy to use as a method for describing the upper-level dynamics. On the other hand the PV analysis provided a summarized picture of the development and the evolution at upper and lower levels, which is directly visible, on the basis of a smaller number of plots compared with the isobaric vorticity analysis. The display of the time sequence of the PV on the appropriate isentropic surface helped in easily understanding the dynamics of the three-dimensional upper level development.
1. Introduction
In recent years, cyclogenesis over the central Mediterranean region has become the subject of considerable research (Prezerakos, 1991,1992; Prezerakos et al. 1999; Karacostas and Flocas, 1983; Flocas and Karacostas, 1996), since these synoptic-scale events cause intense winds, precipitation and temperature drop. Because of the intimate connection between the phenomena and local weather prediction, interest in understanding the characteristics of cyclogenesis over this region is enormous and ongoing.
On the other hand, in the last decade, great emphasis has been placed on the analysis of the isentropic potential vorticity. Although, this dynamic atmospheric parameter was introduced in the 1940’s by Rossby (1940) and Ertel (1942), its application in meteorological research was limited, mainly because of the complexity of its calculation. Since Hoskins et al. (1985) acknowledged the analysis of isentropic potential vorticity as a very important diagnostic tool to understand the mechanisms responsible for atmospheric development better; the interest of the research community has increased enormously in this topic.
According to Hoskins et al. (1985), the potential vorticity analysis on isentropic surface summarizes the combined effect of the vorticity and temperature advection and allows the estimation of the vertical motion. The objective of the present work is to diagnose our case of study in the context of absolute, relative and potential vorticity analysis in order to examine in detail the key dynamical aspects of the cyclonic development. |
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ISSN |
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1319-1039 |
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Journal Name |
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Meteorology, Environment and Arid Land Agriculture Sciences Journal |
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Volume |
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18 |
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Issue Number |
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2 |
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Publishing Year |
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1429 AH
2007 AD |
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Article Type |
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Article |
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Added Date |
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Sunday, October 3, 2010 |
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Researchers
| د. عبدالرحمن خلف الخلف | AL-Khalaf, Abdulrahamn Khalaf | Investigator | Doctorate | akhalaf@kau.sdu.sa |
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