Preliminary results of Convection initiation areas associated with deep convection during RELAMPAGO-CACTI

CANCELADA, MAITE; NESBITT, STEPHEN; VILA, DANIEL; SALIO, PAOLA; VIDAL, LUCIANO

Buenos Aires

Workshop; RELAMPAGO - CACTI Data Analysis Workshop; 2019

Many thunderstorms in Southeastern South America (SESA) stand out in satellite observations as being among the strong on Earth in terms of satellite-based convective proxies, such as lightning flash rate per storm, the prevalence for extremely tall, wide convective cores and broad stratiform regions. Knowing when and where strong convection is initiated presenting a great interest because of the close relationship between convective storms and severe weather phenomena. This paper generates a novel methodology to determine convective initiation areas associated with extreme convective systems.Due to the lack of long records of ground-based radars in the area, overshooting tops from GOES16 over RELAMPAGO-CACTI field campaign are considered to determine extreme convective events. These different extreme convective events generate a large sample allowing to determine convective initiation areas over SESA during multiple years. All events are tracked backward using an adaptive threshold area-overlapping technique with thermal infrared (IR) channel. It was necessary to consider multiple IR temperature thresholds in order to identify areas of deep convection embedded within larger cloud clusters.