Caracterização dos relâmpagos ocorridos na região Nordeste do Brasil, por meio de sensoriamento remoto

Abstract

Due to its aggressive and devastating characteristics, lightning constituted in the history of humanity the central observations point of several scientific communities around the world, causing the evolution of scientific knowledge about the phenomenon. However, our ability to represent its spatial and temporal variability, as well as your relationship with other environmental characteristics, remains a key challenge. It is estimated that about 60-75 million lightning strikes occur annually, which are responsible for the death of approximately 132 people every year in Brazil. The Northeast region of Brazil (NEB) concentrates 18% of all deaths across the entire national territory, and if we consider the population of the different regions, the state of Piauí had the highest mortality rate in the region (1.8 deaths per million); this value being much higher than the national rate (0.8) and NEB (0.5). In this sense, the present work proposed to evaluate the occurrence of lightning in the Northeast region of Brazil, characterizing its relationship with the microphysics of clouds and natural disasters. Within this scope, data from two different orbital platforms were used: i) from the Tropical Rainfall Measuring Mission (TRMM), data from the Lightning Imaging Sensor (LIS), TRMM Microwave Imager (TMI) and Precipitation Radar (PR) sensors were used. The first provides data on the lightning occurrence throughout the Earth's tropical zone and the last two provide information on the clouds microphysical characteristics and estimation of the precipitation rate; ii) from the Geostationary Operational Environmental Satellite (GOES-16), data from the Geostationary Lightning Mapper (GLM) sensors on the occurrence and location of lightning and Advanced Baseline Imager (ABI) were used, a 16-channel sensor, 2 of which are visible , 4 in the near infrared and 10 in the infrared. First, the TRMM data were analyzed in order to seek to establish a relationship between the lightning occurrence and the clouds microphysical characteristics (ice water path, rain water path, freezing height level, convective precipitation and surface precipitation), comparing them according to lightning occurrence classes, spatial location and atmospheric profiles. Subsequently, a distribution of the lightning measured by the GLM was carried out, in order to understand its spatial and temporal variability. Finally, we also evaluate the relationship between the lightning parameters and the occurrence of natural disasters in the NEB. The states of Maranhão, Piauí and Bahia concentrate the regions with the highest lightning density. A higher occurrence lightning is associated with higher values of ice water path (> 38.9 kg.m−2), rain water path (>2 kg.m−2), convective precipitation (>5 mm.h− 1) and surface precipitation (>7 mm.h−1), in addition to slightly higher freezing height level values. Regions with high lightning density (>20 flash.km-2.year-1), on average, do not have lightning with large (>1000 km²), energy (>1500 fJ) and duration (>400 ms). The Intertropical Convergence Zone, in addition to being important for precipitation, is also a system that generates a significant amount of lightning, being commonly related to natural disasters in coverage area. It is expected that, with the establishment of the sites and periods of greater occurrences and the characteristics of lightning, as well as the definition of the participation of each microphysical variable studied in the lightning occurrence, the understanding regarding the phenomenon can increase, in addition to the decrease in fatalities associated with him.