Lightning risk warnings based on atmospheric electric field measurements in Brazil
doi: 10.5028/jatm.2011.03032511

Marco Antonio da Silva Ferro*
Institute of Aeronautics and Space
São José dos Campos/SP – Brazil
marcomasf@iae.cta.br

Jorge Yamasaki
Institute of Aeronautics and Space
São José dos Campos/SP – Brazil
yamasakijy@iae.cta.br

Douglas Roberto M. Pimentel
Institute of Aeronautics and Space
São José dos Campos/SP – Brazil
douglas.roberto.fis@gmail.com

Kleber Pinheiro Naccarato
National Institute for Space Research
São José dos Campos/SP – Brazil
kleberp@dge.inpe.br

Marcelo Magalhães Fares Saba
National Institute for Space Research
São José dos Campos/SP – Brazil
msaba@dge.inpe.br

*author for correspondence

Abstract:
This paper presents a methodology that employs the electrostatic field variations caused by thundercloud formation or displacement to generate lightning warnings over a region of interest in Southeastern Brazil. These warnings can be used to prevent accidents during hazardous operations, such as the manufacturing, loading, and test of motor-rockets. In these cases, certain equipment may be moved into covered facilities and personnel are required to take shelter. It is also possible to avoid the threat of natural and triggered lightning to launches. The atmospheric electric field database, including the summer seasons of 2007/2008 and 2008/2009 (from November to February), and, for the same period and region, the cloud-to-ground lightning data provided by the Brazilian lightning detection network – BrasilDAT – were used in order to perform a comparative analysis between the lightning warnings and the cloud-to- ground lightning strikes that effectively occurred inside the area of concern. The analysis was done for three areas surrounding the sensor installation defined as circles with 5, 10 and 15 km of radius to determine the most effective detection range. For each area it was done using several critical electric field thresholds: +/- 0.5; +/- 0.8; +/- 0.9; +/- 1.0; +/- 1.2; and +/- 1.5 kV/m. As a result of the reduction of atmospheric electric field data provided by the sensor installed in area of concern and lightning provided by BrasilDAT, it was possible, for each of the areas of alert proposals, to obtain the following parameters: the number of effective alarms; the number of false alarms; and the number of failure to warning. From the analysis of these parameters, it was possible to conclude that, apparently, the most interesting critical electric field threshold to be used is the level of 0.9 kV/m in association with a distance range of 10 km around the point where the sensor is installed.

Keywords:

Atmospheric electric field, Electric field-mill, Lightning.

J. Aerosp.Technol. Manag., São José dos Campos, Vol.3, No.3, pp. 301-310, Sep. - Dec., 2011
Received: 06/06/11
Accepted: 20/09/11