JpGU-AGU Joint Meeting 2020

Presentation information

[E] Oral

M (Multidisciplinary and Interdisciplinary) » M-SD Space Development & Earth Observation from Space

[M-SD46] Effects of lightning, severe weather and tropical storms

convener:Mitsuteru Sato(Department of Cosmoscience, Hokkaido University), Yoav Yair(Interdisciplinary Center Herzliya), Xiushu Qie(Institute of Atmospheric Physics, Chinese Academy of Sciences), Yukihiro Takahashi(Department of Cosmosciences, Graduate School of Science, Hokkaido University)

[MSD46-01] Is there a "weekend effect" in precipitation and lightning activity during winter thunderstorms over the Tel-Aviv, Israel metropolitan area?

*Yoav Yair1, Mordecai Yaffe1 (1.Interdisciplinary Center (IDC) Herzliya, Israel)

Keywords:Lightning, Urban Effect, Winter thunderstorms

There is numerous evidence that show changes of lightning frequency above and around (especially downwind of-) major urban areas compared with their rural surroundings. For example, Bell et al. (2009) reported a weekly cycle in lightning frequency in the south-east of the USA, but only a weak signal over major cities. There was a clear midweek increase in storm intensity, indicating that increases in aerosol levels lead to invigoration of storms in regions where convective instability and humidity are high. A similar weekday-weekend difference was reported for the Atlanta, Georgia metropolitan area by Stallins et al. (2012) and by Farias et al. (2009) in Sao-Paulo, Brazil.

We report the analysis of 10 years of winter-time (DJF) pollution, precipitation and lightning data over the Tel-Aviv metropolitan area, Israel's largest and densest urban environment. The region has an area of 2291 km2 and a population of 3.854 million people, and hosts 1 million cars per day during weekdays (Sunday-Thursday) and the overflights of hundreds of airplanes landing at the Ben-Gurion international airport. Hourly aerosol concentrations (PM2.5 and PM10) were obtained from several automatic air-quality stations operated by the Ministry for Environmental Protection. The daily precipitation amounts at the Bet-Dagan Meteorological Center were analyzed on a decadal basis and exhibit a weekend effect with a varying maximum during weekdays. Lightning data obtained from the Israeli Lightning Detection Network (ILDN) for the period showed a similar pattern with enhanced activity during mid-week, with maximum on Wednesday and Thursday. These results suggest that increased activity of lightning during week-days (as compared with the weekend) is caused by increased levels of pollution due to traffic and economic activity. The increased amounts of particles tend to prolong the life-time of storms and their total lightning amounts and change their intracloud/cloud-to-ground flash ratios.