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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-21 20:22 |
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Conference: Bucharest University Faculty of Physics 2008 Meeting
Section: Atmosphere and Earth Science; Environment Protection
Title:
Cloud-to-ground lightning activity in Romania from
2003 to 2007 (POSTER)
Authors:
Bogdan Antonescu, Sorin Burcea, Daniel Victor Carbunaru
Affiliation:
Romanian National Meteorological Administration
E-mail
bogdan.antonescu@meteo.inmh.ro
Keywords:
lightning, climatology, lightning density, positive strikes
Abstract:
The geographical distributions of cloud-to-ground lightning strikes recorded by the National Lightning Detection Network over contiguous Romania for the years 2003-2007 are presented. These characteristics include: total cloud-to-ground flash density, the positive flash density, the percentage of positive flashes, and diurnal and monthly variation of the total number of discharges. Analysis was carried out at 0.2° space resolution, corresponding to about 20-km resolution. Maximum density tops 9 discharges km−2in Olteniei Plain and Jiu’s Defile areas, situated in the southern part of Romania. The monthly mean number of discharges reached a maximum of about 12.5•104 flashes in July. Maximum density of positive cloud-to-ground strikes, higher than 0.08 discharges km−2, was recorded around the cities of Barlad and Suceava, North-Eastern part of Romania. The monthly mean number of positive discharges has a main maximum corresponding to July and a secondary one in May. High values of the annual mean percentage of positive cloud-to-ground flashes are specific to Eastern Romania regions. Monthly mean positive discharge percentage varies between 2% in July and 18% in January. Diurnal variation of discharges has the same characteristics over the year, with a maximum within 1600-1800 LT. When the relationship between lightning activity and ETOPO-2 topographic measurements, at 0.2° x 0.2° resolution, is analyzed, a decrease with altitude can be noticed in total number of discharges. The proximity sounding method was applied in order to point out the physical processes leading to cloud-to-ground lightning flashes.
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