Open AccessLightning phenomenology in the Tel Aviv area from 1989 to 1996
Author(s) -
Yair Yoav,
Levin Zev,
Altaratz Orit
Publication year - 1998
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/98jd00087
Subject(s) - tel aviv , thunderstorm , meteorology , storm , wind shear , atmospheric sciences , lightning (connector) , environmental science , geology , wind speed , physics , power (physics) , quantum mechanics , library science , computer science
We present the results of a continuing survey of lightning characteristics in Tel‐Aviv, Israel, for the period 1989–1996, based on daily registrations of a CGR3 lightning flash counter [ Mackerras , 1985]. The lightning season in Israel lasts from October to April, and the long‐term average of the annual flash density in the Tel‐Aviv area was found to be 4.7±2.3 km −2 y −1 . The mean intracloud/cloud‐to‐ground flash ratio was found to be 2.5±1.3, with maxima in the autumn months. This may be attributed to the higher altitudes of the −10°C and −25°C isotherms (which signify the locations of charge centers) and to the weaker wind shears that occur in these months. The average fraction of positive ground flashes (PGF) in Tel‐Aviv thunderstorms was F = 0.16±0.08. Storms that exhibited larger than average PGF fraction were found to be subjected to a strong shear of the horizontal wind. The observed empirical relation between the PGF fraction and the intensity of the wind shear W (in m s −1 km −1 ) was log F = 0.0305W + 0.073.