IPB University Meteorologist Reveals the Reason for the Large Number of Lightning in Bogor
In addition to having high rainfall almost all year round, Bogor is also known as the region with the most lightning days as reported by Guinness World of Record in 2019. The combination of abundant rainfall and high lightning frequency strengthens Bogor’s reputation as one of the cities with the most lightning activity in the world.
IPB University Meteorologist, Sonni Setiawan, SSi, MSi revealed the reason for the phenomenon of many lightning bolts in Bogor.
“Lightning is one of the phenomena in a thunderstorm in the form of flashes that occur in cumulonimbus clouds. These cumulonimbus clouds are formed due to convective motion, when parcels of moist air move vertically upwards due to buoyancy forces,” Sonni explained.
During this process, he continued, the moist air then undergoes cooling and eventually turns the water vapor in these moist air parcels into clouds.
“These convective clouds combine to form cumulonimbus clouds, and this is what causes thunderstorms,” he explained.
This IPB University lecturer from the Department of Geophysics and Meteorology, Faculty of Mathematics and Sciences (FMIPA) explained that this convective motion cannot occur spontaneously, it needs external forcing that provides impulses for moist air parcels to move convectively.
These forces include turbulence, topography, the presence of uneven radiative heating at the surface, the presence of mountains or large mountains, and the presence of large-scale convergence at the surface.
“One of the five forces interacts with wind variations in the vertical direction (vertical wind shear) so that these cumulonimbus clouds can develop into thunderstorms,” he said.
Furthermore, Sonni revealed that lightning occurs when there is a separation of electric charges in cumulonimbus clouds, which causes the distribution of electric charges in the cloud to be in an imbalance condition, so that electric jumps or lightning occur as an effort to balance these charges.
Regarding the lightning phenomenon in Bogor, Sonni also explained that the electric charge in cumulonimbus clouds is caused by the presence of electrolyte compounds in the droplets (water drops). When these droplets collide with each other, there is a separation of electrical charges in the cumulonimbus cloud. These electrolyte compounds come from aerosols dissolved in the cloud drops, and these aerosols can be salts, and pollutant compounds.
“The combination of turbulent effects, differences in surface heating, topography, large mountains, and large-scale convergence, with wind shear and the presence of pollutant gases makes the frequency of lightning events in Bogor very high,” he explained.
In addition, sunspot activity (black spots on the surface of the sun) can increase lightning activity in cumulonimbus clouds. Sunspots have the potential to affect lightning activity in the atmosphere. However, Sonni said, it should be noted that sunspots have an 11-year period.
“The phenomenon of lightning in the Bogor area has not been studied intensively so this is an opportunity for students to be able to study further,” he concluded. (Rani/Rz) (IAAS/Aly)
