SYNOTIC ANALYSIS OF THE INTENSE PRECIPITATION OBSERVED ON THE DAY 11/09/2002 IN SANTA MARIA, RS

Ano: 2007 | Volume: 29 | Número: 1

Autores: Everson Dal Piva Dal Piva

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Resumo Inglês:

This paper analyzes the intense precipitation observed in the morning of September 11, 2002, in the city of Santa Maria, in the center of the Rio Grande do Sul State, Brazil. The regional CPTEC / INPE reanalysis data, GOES-8 satellite images and the BRAMS. The intensaprecipitation was generated by pre-frontal convective cells, triggered by the approach of a cold front associated with an extratropical cyclone located in the extreme south of South America, and fed by the humidity of the Amazon basin. Important meteorological parameters indicate that the storm that struck Santa Maria may have been a supercell, a system that unleashes the vast majority of tornadoes distributed throughout the world. The simulation with regional model showed similarities and discrepancies with respect to observation. As similarities stand out: beginning of the convection around 1700UTC in the Brazil-Argentina border; propagation of this convection to the southeast towards the center of the State of Rio Grande do Sul; and formation of new cells for west direction towards Argentina. As discrepancies, the simulation presented a spatially more concentrated precipitation than the one observed; the model presented a tendency to generate a large amount of precipitation at the bottom of the valleys; and the spread of convection to the northwest in direction to Paraguay was slower than the observations indicate. the simulation presented a spatially more concentrated precipitation than the one observed; the model presented a tendency to generate a great amount of precipitation at the bottom of the valleys; and the spread of convection to the northwest in direction to Paraguay was slower than the observations indicate. the simulation presented a spatially more concentrated precipitation than the one observed; the model presented a tendency to generate a great amount of precipitation at the bottom of the valleys; and the spread of convection to the northwest in direction to Paraguay was slower than the observations indicate.