Seminário: Tropical TGF Paradox: A Perspective From TRMM Precipitation Radar

16/07/2021 - 14:00
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O seminário do Departamento de Ciências Atmosféricas será apresentado pelo Prof. Dr. Carlos Augusto Morales Rodriguez (IAG/USP)

Resumo: Terrestrial Gamma ray Flashes (TGFs) have been detected in space above thunderstorms worldwide, but their main triggering mechanism has not yet been fully understood. In the last two decades, several measurements from ground and satellite instruments have provided information to help our understanding. For instance, TGF emissions are concentrated in the tropics and one of the possible theories suggests to be related to intense intracloud lightning processes produced by thunderstorms that have considerable vertical charge center separations. Although African thunderstorms have the highest lightning activity in the world, they produce fewer TGFs per number of lightning flashes than thunderstorms in America and the Southeast Asia tropical regions, posing a paradox. To explore this asymmetry, this study employed 3D measurements from the Precipitation Radar on board the Tropical Rainfall Measuring Mission (TRMM) satellite to describe the main precipitation vertical structure observed in the three most important tropical thunderstorm regions in the world (Climatology) and in the thunderstorms that produced TGFs. African thunderstorms are taller, smaller, having more ice aloft and lightning discharges. TGF thunderstorms show similar precipitation variation decay with height, are taller and more intense, in addition to showing different vertical cloud charge structure and larger distance between the opposite charge layers.
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