Microphysical properties of precipitation in thunderstorms with upward lightning

• Grant number: 16/17821-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): January 01, 2017
• Effective date (End): December 05, 2018
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Meteorology
• Principal Investigator: Rachel Ifanger Albrecht
• Grantee: Jessica Cristina dos Santos Souza
• Host Institution: Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 15/14497-0 - Nowcasting of intense thunderstorms and understanding of the physical processes inside clouds: the SOS-CHUVA (Severe Weather Observation System), AP.PFPMCG.TEM
• Associated scholarship(s): 17/13293-7 - Electrical and hydrometeor structure of thunderstorms that produce upward lightning, BE.EP.IC

Abstract

Lightning triggered by tall structures has been studied since the end of 1930 decade. In Brazil, the first Upward Lightning (UL) was registered in 2012 at Pico do Jaraguá, the highest point in Sao Paulo city. This type of lightning have has its initiation associated to cloud-to-ground lightning at convective regions of the cloud, which intensify the local electric field at the top of tall structures by the propagation of negative leaders in the stratiform region directly over the tower triggering upward leaders of UL towards the cloud base. The objective of this research proposal is to determine the microphysical properties of thunderstorms that generate UL by determining the hydrometeor types present in the convective and stratiform precipitation based on polarimetric radar observations. More specifically, it will be analyzed the spatial and temporal distribution, the vertical structure of precipitation and the electrical activity of the thunderstorms that generate UL with concomitant measurements of different sensor (video, lightning and radar) of 56 UL that occurred during 17 different thunderstorms between 2014 and 2016. Lastly, based on these results, these same characteristics will be sought in other thunderstorms in order to identify possible UL in other tall structures of large urban centers such as the metropolitan regions of São Paulo and Campinas, which are the two most populous regions of Brazil and are in constant process of verticalization. The results of this research project will be important to increase the understanding of the phenomenon and the storm evolution and the predictability of UL, in addition to determining the real impact of cities verticalization on lightning incidence. (AU)