engleski

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

In this study characteristics of lightning activity, such as type and amplitude of lightning strokes in convective clouds with overshooting tops (OT), are analyzed. OTs are specific cloud-top signatures representing a strong updraft, which in some cases can penetrate through the tropopause region into the lower stratosphere. The focus was on the warm part of the year (May-September) during 2009. The study area covers a 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). Locations and times of the detected OTs were compared to the distribution and types of the lightning strokes, provided by the Lightning Location System, a part of the International Lightning Detection Network in Europe (LINET). For each satellite pixel meeting the OT criteria, 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 present the characteristics of lightning in the vicinity of the OTs which might give an idea about the connection between the occurrence of the strongest updraft, represented with the OT in the cloud and the change in the lightning activity.

overshooting top ; lightning ; Meteosat 9 data ; LINET data

nije evidentirano