engleski

Characteristics of lightning activity in deep convective cloud with the overshooting tops

In this study, characterictics of lightning activity, such as type, height and amplitude of lightning strokes, in the penetrating clouds, i.e. convective clouds with overshooting tops (OT) are analyzed. The focus was on the warm part of the year (May-September) during 2009 and 2010. The study area covers region from approximately 41°N 8°E to 49.5°N 24°E. Deep convective clouds with OTs were detected from the Meteosat 9 data, using a so called COMB method based on the infrared window (IRW, 10.8 μm) channel and the absorption channels of water vapor (WV, 6.2 μm) and ozone (O3, 9.7 μm) in form of brightness temperature differences (BTD). COMB method combines the criteria for the IRW brightness temperature and the criteria for two BTDs, WV-IRW and O3-IRW. All pixels with O3-IRW BTD larger than 13 K in the region where IRW brightness temperature is lower than 215 K and WV-IRW BTD larger than 4 K are characterized as OTs. Lightning data were provided by the Lightning Location System, which is part of the International Lightning Detection Network in Europe (LINET). The LINET system detects total lightning discharge, but it also separately detects cloud to ground (CG), or intra cloud and cloud to cloud strokes (IC). For each satellite pixel meeting the OT, occurrence of lightning discharge was searched 5 min before and after the time of the scan within the range of 0.05° from the pixel position. The results will present the characteristics of lightning in the vicinity of the OTs

lightning; overshooting top; brightness temperature difference

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