Sistemas convectivos de Mesosescala associados a eventos extremos de precipitação sobre o semiárido do Nordeste do Brasil

Abstract

This work presents a study of the physical and morphological characteristics of the Mesoscale Convective Systems (MCS) that occurred between 2010 and 2011 on the semi-arid region of Northeast Brazil in situations of rainfall weak (WRE) and intense (HRE). For this, Geostationary Operational Environmental Satellite (GOES-12) satellite images were used in the infrared channel, obtained every 30 minutes. These data were used by the Forecasting and Tracking the Evolution of Cloud Clusters (ForTraCC) to identify, track and determine the characteristics of MCS. In addition, daily rainfall data, provided by the National Water Agency and by the National Institute of Meteorology were used to identify extreme events by quantiles analysis. The results showed that HRE were more frequent WRE, especially in March. Both MCS related to WRE and HRE presented, in their majority, irregular type format. The mean temperatures at the top of the cloud were similar (-52°C), but the minimum temperatures at the top of the MCS had higher occurrences in the warmer months, with a value of -79°C. The MCS related to HRE presented larger sizes. From these results it is possible to affirm that MCS acting on the Brazil Northeast Semiarid present intense vertical development, possibly favored by the presence of one or more atmospheric systems acting at the same time