Características físicas dos sistemas convectivos de mesoescala que afetaram o Rio Grande do Sul no período de 2004 a 2008

in this work, using fortracc method (forecasting and tracking of active cloud clusters), were studied, from 2004 to 2008, the seasonal physicsfeatures of the mesoscale convective systems (mcs), whose genesis and maintenance happened southward of 20os, with life cycle longer than 6 hours, with spontaneous initiation and normal dissipation and that reached the rio grande do sul (rs) state (mcs). channel 4 geostationary operational environmental satellite (goes) images from 2004/01/01 to 2008/12/31, with 4 km × 4 km spatial resolution in the subsatellite point and 1/2 hour temporal resolution were used. these images were provided by dsa/cptec/inpe (divis？o de satélites e sistemas ambientais do centro de previs？o de tempo e estudos climáticos do instituto nacional de pesquisas espaciais ) and were the data basis to the fortracc method. the results showed that from mcs: i) the majority occurred in the warmest quarter and showed lifetime between 6 and 12 h; ii) those with higher lifetime covered larger areas; iii) the largest and most long were observed in jas (jul, aug, sept) due to higher occurrence of cold fronts in this quarter that favors greater convective activity; iv) presented the three phases of the life cycle distributed throughout the day; v) had their initiation inside and around the grid that covers rs, with preferential initiation over the continent; and vi) presented mean preferential trajectory from west to east.