WIT Press


Temporal And Spatial Characterization Of Cloud-to-ground Lightning Activity Over Iberian Peninsula

Price

Free (open access)

Paper DOI

10.2495/RISK020401

Volume

31

Pages

Published

2002

Size

496 kb

Author(s)

F. de Pablo, L. Rivas Soriano & S. Mendonça Leite

Abstract

Temporal and spatial characterization of cloud-to-ground lightning activity over Iberian Peninsula F. de Pablo1, L. Rivas Soriano1, & S. Mendonca Leite2 1 Dept. of Atmospheric Physics, Faculty of Sciences, University of Salamanca, Spain 2 Geophysical Center of the University of Lisbon, Faculty of Sciences, Lisbon, Portugal Abstract The quantitative assessment of the impact on society of weather and climate extremes is challenging and recent years have seen a tremendous increase in economic losses from weather hazards. Is necessary to know the changes in the frequency and/or intensity of extreme events to evaluate the trend in losses. So the lightning activity plays a fundamental role as a cause of weather-related deaths, property damages and power system breakdowns. The temporal and spatial distribution of cloud-to-ground lightning activity in the Iberian Peninsula have been studied, using data of years 1992-1994.0ver 2.2 million cloud-to-ground lightning flashes were recorded. The highest lightning activity was found in the summer (79% of all lightning events in the months May to September and the diurnal variation shows a single peak with the maximum at 1700 local time. Just over 11% of all lightning flashes are observed between 0700 and 1100 local time; which represents the contribution of frontal thunderstorms to lightning activity. The lightning polarity changes throughout the year: during the warmer months positive flashes contribute only 5.9% whereas this percentage increases to 13.1% in the colder months. The geographical distribution of cloud-to-ground flashes shows a clear relationship with orography, with maximum lightning activity over Pirineos. The average maximum flash density is found to be 3.3 flashes km-2yr-1.

Keywords