A Comparative Analysis Between Weather Radar Images and Density Fields of Lightning Occurrences for Severe Convective Events - Abstract

Sep 8, 2026

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This work compares CAPPI weather radar images with corresponding density fields of cloud-to-ground lightning occurrences produced by the EDDA tool. Precipitating structures visible in radar imagery can be correlated with denser regions in lightning occurrence fields. These density fields support monitoring of convective events in regions without weather radar coverage. EDDA generates smooth two-dimensional lightning-density fields and enables near-real-time processing for temporal animations, supporting quasi real-time convective monitoring and operational nowcasting.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages4

Reading Time10 min

AccessFree to download

Abstract

1. Introduction

2. Weather radar

3. The EDDA software tool

A COMPARATIVE ANALYSIS BETWEEN WEATHER RADAR IMAGES AND DENSITY FIELDS OF LIGHTNING OCCURRENCES FOR SE VERE CONVECTIVE EVENTS Mirian Caetano1, Marcelo Barbio Rosa1, Stephan Stephany2 1.Weather Forecast and Climatic Studies Center (CPTEC) , National Institute for Space Research (INPE) 2. Laboratory for Computing and Applied Mathematics (LAC), National Institute for Space Research (INPE) {mirian.caetano, [marcelo.barbio}@cptec.inpe.br](marcelo.barbio}@cptec.inpe.br) [stephan@lac.inpe.br](stephan@lac.inpe.br) Abstract This work provides a brief discussion about the comparison between CAPPI weather radar images and the corresponding fields of density of occurrence of cloud-to-ground lightning generated by the software tool EDDA. It is possible to correlate the precipitating structures observed in the radar images to the denser areas in the density field of occurrence. Such density fields were already employed as a mean for monitoring convective events in areas that are not covered by weather radars. Keywords: meteorological radar, atmospheric electrical discharges, convective systems 1. Introduction The visualization of the density field of cloud-to-ground lightning occurrences can be useful for monitoring severe convective activity, since it provides a smooth twodimensional field of the lightning occurrences for a given time interval. These occurrences are tipically very sparse in time and space. The corresponding density field is generated by the EDDA software from lightning data provided by the RINDAT sensor network. Most of the Brazilian territory is convered by this network. EDDA stands for Estimator of Density of Atmospheric electrical Discharges, in Portuguese. Its output format is compatible with the GRADS visualization software, commonly employed in Meteorology. In addition, the EDDA software provides near real time processing according to the availability of lightning data making possible to generate animations that show the temporal evolution of the lightning occurrence density field. The radar data employed in this work were provided by 3 weather radars located in the São Paulo State. Constant Altitude Plan Position Indicator (CAPPI) images were derived from the radar data and a small set of severe convective events was then selected from the CAPPI images. The corresponding images for the lightning density of occurrence were also generated. A comparative analysis of both sets of images from each convective event showed a correlation between the precipitating structures observed in the radar images and the more intense parts of the discharge density field of occurrence. Such correlation suggests that lightning density of occurrence fields may be useful to monitor convective activity in quasi real time in areas where a weather radar coverage is not available. It can be concluded that the EDDA software has a potential use for operational Meteorol- ogy, particularly for nowcasting. 2. Weather radar Weather radars allow to observe the vertical profile of clouds by measuring the cloud reflectivity (in dBZ) by scanning the sky in both azimuth and elevation. Constant Altitude Plan Position Indicator (CAPPI) images are 2D horizontal intersections of the 3D reflectivity measurements. The reflectivity values are mapped to the precipitation rate by a assumed R-Z relation. However, radar mesurements are limited to a short range (tipically 240 km) since the line of sight of its beam gets higher and higher due to the Earth surface curvature (CALHEIROS, 2009) . Nowadays the use of weather radar for the monitoring and study of atmospheric precipitation is widespread and most countries may afford to have high temporal and spatial resolution weather radars, but only USA, Europe and some countries make use of a network of weather radars with full geographical coverage. The weather radar data employed in this work were provided by the IPMET/UNESP (IPMET, a Meteorology research institute linked to the São Paulo S

FAQs

What does the study compare between radar and lightning data?

The study compares CAPPI weather radar images with lightning density fields of cloud-to-ground lightning occurrences generated by EDDA.

How are lightning density fields generated and what are they used for?

EDDA estimates lightning occurrence density from records provided by the RINDAT sensor network, producing smooth 2D fields. These fields are used to monitor convective events, including in areas without radar coverage.

What is the main finding regarding the relationship between radar structures and lightning density?

A correlation is observed between precipitating structures in radar images and more intense parts of the lightning discharge density field, suggesting usefulness for quasi real-time monitoring.

Sep 8, 2026

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