ANALYSIS OF THE DOWNBURSTS OCCURRENCE IN BRAZIL

Authors

  • Elias Galvan de Lima Programa de Pós-graduação em Engenharia Civil, UFRGS
  • Acir Mércio Loredo-Souza Programa de Pós-graduação em Engenharia Civil, UFRGS

DOI:

https://doi.org/10.5902/2179460X16212

Keywords:

Downburst. CAPE. CINE. Severe weather

Abstract

http://dx.doi.org/10.5902/2179460X16212

Downbursts are meteorological phenomena formed from severe convective storms and give rise to strong gusts of wind. When there is intense entrainment of dry and cold air at high levels through the clouds of deep vertical development it is established a phenomenon called evaporative cooling. This phenomenon rise up masses of dense and cold air inside the cloud that keeps sustained by convective currents until the moment that the downward forces outweigh the upward forces. At this moment streams of descend air called downdrafts are established, they fall to the ground and then spread horizontally on a ring shape. This study aims to analyze the occurrence of this phenomenon in the southern Brazil through the characteristics that define the occurrence of downbursts suggested in the literature. Because of the importance of knowledge of the occurrence of environments in which downbursts are favorable to occur, it is analyzed the influence of index Convective Available Potential Energy (CAPE) and Convective Inhibition Index (CINE) on the occurrence of winds generated by downbursts.The results show that the use of indices CAPE and CINE on an isolated form in the definition of environments favorable to the occurrence of convective downbursts are not sufficient and is suggest the observation of other meteorological variables and index on this process. Through two case studies, it was observed winds from storms with characteristics of downbursts, thus it is observed the occurrence of the phenomenon in southern Brazil.

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Published

2015-03-07

How to Cite

Lima, E. G. de, & Loredo-Souza, A. M. (2015). ANALYSIS OF THE DOWNBURSTS OCCURRENCE IN BRAZIL. Ciência E Natura, 37, 32–38. https://doi.org/10.5902/2179460X16212