First detection of transient luminous events associated with winter thunderstorms in the eastern Mediterranean

During the winter of 2005-6, optical ground-based observations were performed to detect transient luminous events (TLEs) above winter thunderstorms in the vicinity of Israel and the eastern coastline of the Mediterranean Sea. Two sites were used: the Tel Aviv University (TAU) campus in Tel-Aviv (32.5N, 34.5E) and the Wise astronomical observatory in the Negev desert (30.6N, 34.76E). We also conducted ELF and VLF electromagnetic measurements from the TAU array in southern Israel. In 4 different winter storms we detected 30 events: 26 sprites and 4 elves. The detection ranges varied from 250 to 450 km. Sprites were found to be produced exclusively by +CGs that can be traced to active cells with a vertical dimension of 5-7 km and cloud top temperature ∼-40°C, embedded in a much larger matrix of stratiform cloudiness. This configuration closely resembles the conditions for winter sprites in the Hokuriku region of Japan.