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| Author(s): |
João Rafael Dias Pinto
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Instituto Astronômico e Geofísico (IAG/SBD) |
| Defense date: | 2010-03-15 |
| Examining board members: |
Rosmeri Porfirio da Rocha;
Tercio Ambrizzi;
Manoel Alonso Gan
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| Advisor: | Rosmeri Porfirio da Rocha |
| Abstract | |
The atmosphere is a complex thermodynamic system in which energy generation, conversion and dissipation play a key role in the development and maintenance of the synoptic scale movement systems. In this paper, the Lorenz energy cycle in a limited area was applied for three cases of cyclogenesis, where each one of them formed in an important cyclogenetic region in the east of South America. Furthermore, the synoptic conditions were analyzed, as well as the evolution of the tridimensional structure, from its early formation until its decay. The analysis showed that the cyclone, which formed on Brazil south/southeastern coast, originated through a cut off low in the mid levels on a weak baroclinic region. The energy conversions indicated the system extracted kinetic energy from the basic flow, showing that the barotropic instability was dominant in its development. The system that occurred in the Rio da Prata mouth had features of a bomb-type cyclogenesis with fast intensification. Moreover, due to this event, the fronts seclusion were observed. The baroclinic nature with a strong contribution from the available potential energy generation term, through the latent heat release of the convection, can be observed by the conversion terms. Meanwhile, the system of the Argentina south coast presented a classical baroclinic development (which has the conversion from eddy available potential energy to eddy kinetic energy) of an extratropical cyclogenesis, from the wave amplification until the final occlusion of the associated frontal system. Based in this analysis, it is worthy to note that both the development and structure of the cyclogenesis that occur in the South American eastern coast can present varied features, which are often not related to classical cyclogenesis. (AU) | |