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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-23 18:30 |
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Conference: Bucharest University Faculty of Physics 2017 Meeting
Section: Atmosphere and Earth Science; Environment Protection
Title:
The dynamic and thermodynamic study of the of potential vorticity anomaly impact on the troposphere
Authors:
Meda Daniela ANDREI (1,2), Mirela PIETRIȘI (1,2), Sabina ȘTEFAN (1)
*
Affiliation:
1) University of Bucharest, Faculty of Physics, P.O.BOX MG 11, Magurele, Bucharest, Romania
2) National Meteorological Administration, Bucuresti-Ploiesti Ave., No. 97, 013686, Bucharest, Romania
E-mail
meda.georgescu@gmail.com
Keywords:
potential vorticity , tropopause fold, cyclones
Abstract:
Although the concept of potential vorticity has been used, for decades, in countless scientific papers, to describe the dynamic and thermodynamic behavior of various processes in the atmosphere, in practice the “Potential Vorticity (PV) thinking” is not as widespread. So, the aim of the paper is to present how using PV anomalies it is possible to evaluate both the stability of the atmosphere and the absolute vorticity. The PV anomaly is generated by dry stratospheric air intrusion into the upper troposphere. A positive potential vorticity anomaly with high amplitude in the upper troposphere represents a tropopause fold. It contributes to the joining of the low and high levels of the troposphere. When this kind of perturbation, with related divergence zone and vertical motion, overlaps a low level baroclinicity, a cyclone may develop. Such a situation happened on 20 February 2017, when over the Black Sea basin rapidly formed and evolved a cyclone. This rapid ciclogenesis affected weather of the southeastern part of Romania by intense wind and rain. To demonstrate the influence of the dynamical tropopause fold were analyzed the meteorological fields as the outputs of the ECMWF global numerical model and ALARO limited area numerical model. We especially took into account the potential vortictiy at 300 hPa, 1.5 PVU surface heights, isotaches of the wind on the 1.5 PVU surface, vertical cross sections of relative humidity and potential vorticity, and WV satellite date. The study have shown the importance of this kind of dynamical and thermodynamical approch for improving the weather forecast related to cyclones with upper air precursor.
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