Abstract
Abstract. Cloud-to-ground (CG) lightning flash data collected by the lightning detection network installed at the Korean Meteorological Administration (KMA) have been used to study the urban effect on lightning activity over and around Seoul, the largest metropolitan city of South Korea, for the period of 1989–1999. Negative and positive flash density and the percentage of positive flashes have been calculated. Calculation reveals that an enhancement of approximately 60% and 42% are observed, respectively, for negative and positive flash density over and downwind of the city. The percentage decrease of positive flashes occurs over and downwind of Seoul and the amount of decrease is nearly 20% compared to upwind values. The results are in good agreement with those obtained by Steiger et al. (2002) and Westcott (1995). CG lightning activities have also been considered in relation to annual averages of PM10 (particulate matter with an aerodynamic diameter smaller than 10 μm) and sulphur dioxide (SO2) concentrations. Interesting results are found, indicating that the higher concentration of SO2 contributes to the enhancement of CG lightning flashes. On the other hand, the contribution from PM10 concentration has not appeared in this study to be as significant as SO2 in the enhancement of CG lightning flashes. Correlation coefficients of 0.33 and 0.64 are found between the change in CG lightning flashes and the PM10 and SO2, respectively, for upwind to downwind areas, suggesting a significant influence of the increased concentration of SO2 on the enhancement of CG flashes.
Highlights
The urban effect on enhancing cloud-to-ground (CG) lightning activity over and downwind of cities has first been documented by Westcott (1995)
The percentage increase in the flash density found in this study corresponds well with the results reported by Wescott (1995) and Steiger et al (2002), but it is bit low compared with the results found by Pinto et al (2004)
Results indicate a significant increase of nearly 60% and 42% in the negative and positive flash density, respectively, over and downwind of Seoul compared to the nearby surrounding areas
Summary
The urban effect on enhancing cloud-to-ground (CG) lightning activity over and downwind of cities has first been documented by Westcott (1995). Orville et al, 2001; Steiger et al, 2002; Soriano and Pablo, 2002) Most of these studies have ascribed the effect to the urban heat island circulation, along with a possible role for air pollution. A long-term study conducted by Steiger et al (2002) on the percentage of positive flashes and peak current over Houston, Texas was the first to investigate the urban effect on lightning characteristics in these categories. After that a long-term analysis over the city of Houston has been carried out by Orville et al (2001) and they reported an association between urban heat island and anthropogenic pollution in the enhancement of flash density over and downwind of the urban area. As far as our knowledge is concerned, this is the first long-term study of the urban effect on lightning activity over a large city on the Korean peninsula
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
