Lightning is caused by electron jump from negative charged cloud to positive charged ground. ITB Professor, Prof. Dr. Dipl. Ing. Ir. Reynaldo Zoro explained that there are three conditions to meet to generate lightning. The first condition is sun heat that evaporates water, the second condition is floating particles on the air coming from sea salt or industrial pollutant, and the third is humidity.

Indonesia’s location on the equator line adds more to frequent lightning occurrences. He said that lightning is generated by Cumulonimbus, which contain positive (+) and negative (-) charges. The electrons gather above the cloud while the protons gather below. These particles then rub against each other, and when the energy is enough it is released in the form of lightning.

Usually, Prof. Zoro said, lightning occurs during rainy season. This lightning comes from either positive or negative charge, from cloud to ground or vice versa. If the tip of lightning branch is facing downward, the cloud comes from cloud to ground and vice versa. “The most frequent is the negative charge from cloud to ground,” he explained.

Lightning is a 'Friend'

This professor in Electrical Power Research Group of School of Electrical Engineering and Informatics of ITB (STEI-ITB) said that lightning is a friend of lives on earth. Many benefits come along with lightning. “Lighting is not be afraid of. It generates nitric carried by rain water and good for plants. Lightning also generates ozone that shields against ultraviolet. So lightning is actually a friend of life,” he said.

Regarding lightning that strikes people or damages electronics, Prof. Zoro said that people are yet to understand about lightning. Lightning, he explained, often strikes taller buildings. Hence, a building or house that is taller than its surrounding should install lightning rod.

On an open space such as rice fields or football field, people should stop their activities or find shelter when signs of lightning emerge. People can close their legs and bend almost parallel to the ground. Leaning on a tree should be done cautiously because there might be propagation. “When leaning on a tall tree, keep a minimum of one meter distance because there might be propagation,” he added.

“If we are on a rice field and taking shelter on a gazebo, we should consider that the gazebo is the tallest on a rice field, and hence need lightning rod attached to the sides of gazebo with a distance of more than 1 meter,” he explained.

He said that West Java consists of frequent lighting occurrence areas, such as Bogor and Majalengka. ITB have built lightning rods on those areas such as on Kertajati Airport to prevent problems to air navigation devices when airplanes take-off. “ITB also contribute in building lightning rods, such as on Pertamina’s oil refinery in Cilacap, on Kertajati Airport, on Petrokimia Gresik, and also on football fields,” he said.