Jakarta –
When corona virus began to spread and many places various countries did lockdown for physical distance restrictions, rarely available lightning. That’s according to a study. It turns out that this has something to do with human activities.
During lockdown, people use less energy and spend more time at home. As a result, the air and water become cleaner, the world can rest for a moment and feel calm.
Now, researchers think they have discovered another impact of the lockdown. They believe that the tiny particles in atmosphere so-called aerosols contribute to lightning.
Well, human activities such as burning fossil fuels release aerosols. As quoted from Discover Magazinebecause humans release less aerosol during lockdownaerosol concentration in atmosphere decrease.
Last month, researchers at the American Geophysical Union in New Orleans presented findings showing that this drop in atmospheric aerosols coincided with a decrease in intensity. lightning.
Earle Williams, a meteorologist at the Massachusetts Institute of Technology who presented the research, said his team used three different methods to measure lightning.
“All the results show the same trend i.e., reduced lightning activity is associated with reduced aerosol concentrations,” he said.
Effect of human activity on lightning
Some aerosols in atmosphere can collect water vapor and form cloud droplets. Williams says that when there is more aerosol, the water vapor in the cloud is distributed among more droplets, so the droplets are smaller and less likely to combine into larger raindrops.
These smaller droplets remain in the cloud, helping to form tiny hailstones called graupels and even smaller ice crystals. The collision between the graupel and the crystal results in a negatively charged graupel in the lower center of the cloud and a positively charged crystal in the upper part of the cloud. Scientists think the large difference in charge between these two halves of the cloud causes the lightning.
“But when the pollution is reduced and the clouds form larger and warmer raindrops, they form a cloud of ‘starving’ ice particles needed for charge separation, and reduces lightning activity,” Williams said.
When countries go into lockdown at the start of a pandemic, humans emit less aerosol into the atmosphere. Production at power plants that burn fossil fuels has fallen.
People also use cars less often. Car traffic has a major impact on the production of surface aerosols. Similarly, pollution from air travel decreased significantly,” said Williams.
This reduction in pollution is likely the main reason why Williams and his colleagues observed a decrease in lightning activity, which includes lightning striking the ground, as well as lightning within clouds and lightning between clouds and air.
One of the researchers’ methods, which captures multiple intracloud flashes (the most common type of lightning), measured 19% fewer flashes in the period March 2020 to May 2020 compared to the average number of lightning flashes over the same three-month period in 2018, 2019 , and 2021.
“Nineteen percent is a pretty big reduction,” Williams said.
Another method, looking at the global electromagnetic resonance is called Schumann resonance. Williams said their intensity is thought to be proportional to the number of lightning flashes that occur, and these measurements also show that there will be less lightning during 2020.
Moreover, the results show that places with reduced aerosol atmosphere the more dramatic ones tend to also have the greatest lightning reduction.
Southeast Asia, Europe, and much of Africa experienced some of the largest reductions in both atmospheric aerosol and lightning, while the Americas experienced less dramatic changes. Williams said he wasn’t sure why there was a weaker drop in aerosol concentrations in the Americas, but he pointed out that the increase in aerosol concentrations in northern South America could be due to the fires.
One of the reasons researchers want to understand lightning is because it affects the atmosphere. Williams said that lightning strikes produce nitrogen oxides, which contributes to air pollution. “The chemistry of the atmosphere is definitely influenced by lightning activity,” he said.
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(rns/afr)
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