LIGHTNING
1. Context
Soaring global temperatures could lead to more "hot lightning" strikes in many parts of the world, a new study has found. It added that this type of lightning is more likely to ignite wildfires than typical lightning.
2. What is lightning and how does it occur?
- Lightning is an electrical discharge that occurs when there is an imbalance between the storm clouds and the earth or even within the clouds.
- Scientists believe that for lightning to occur, positive and negative charges must separate within a cloud.
- This happens, according to the National Oceanic and Atmospheric Administration (NOAA), when the water droplets in the bottom part of the cloud are moved upwards, where the much colder atmosphere freezes them into small ice crystals.
- As these small ice crystals continue to go up, they gain more mass and eventually become so heavy that they start to fall down to earth.
- This causes a system in which ice crystals going down collides with the water vapors coming up, leading to the accumulation of positive charges on the top of the cloud and negative changes gathering at the base, while the atmosphere between them in the cloud acts as an insulator.
- When the positive and negative charges grow large enough, their strength overpowers the insulating properties of the properties.
- As a result, the two kinds of changes meet with each other and produce lightning.
- Although most of the lightning takes place within the clouds, sometimes it is directed towards Earth also. With the base of the cloud becoming negatively charged, positive charges start accumulating on tall objects, like trees, poles, and buildings.
3. Why is it a matter of concern?
- Data from the National Crime Records Bureau show that since 2005, lightning has been responsible for at least 2,000 fatalities annually.
- Rural areas account for more than 90% of lightning-related fatalities,
- It is not considered a natural calamity, thus unlike in the case of floods or earthquakes, the afflicted people are not entitled to government compensation.
4. Where are the lightning hotspots around the world?
- It has been discovered by scientists at the Smithsonian Tropical Research Institute (STRI) in Panama that lightning strikes the tropics more than 100 million times a year.
- Asia, South America, North America, Australia, and Africa are the other continents having the highest concentration of lightning hotspots.
- According to experts, lightning strikes are expected to rise by 25-50% as a result of climate change.
5. Findings of the latest study
- The researchers analyzed 5,858 selected lightning-ignited fires based on satellite images of US wildfires between 1992 and 2018 and found that approximately 90 percent of them might have been started by "hot lightning" strikes.
- Also known as long continuing current (LOC), this type of lightning strike can last from around 40 milliseconds to nearly a third of a second.
6. Why Hot lighting has more potential of triggering a wildfire than typical lightning?
- Lightning with continuing currents can transport more energy from cloud to ground than typical lightning. When lightning with continuing currents attaches to ground or vegetation, they produce more Joule heating and higher temperature than typical lightning, increasing the probability of ignition.
- With the help of computer simulations, the researchers also looked at the frequency of "hot lightning" strikes and observed that as the atmosphere warms, there might be an increase of 41 percent in the incidents of LCC strikes by 2090.
- This means that the rate of such lightning flashes could jump from three strikes per second globally to four strikes per second. Meanwhile, the frequency of all cloud-to-ground strikes might increase to nearly eight flashes per second, a 28 percent jump.
- According to the study, the areas that might witness a significant increase in wildfires triggered by the LCC strikes are Southeast Asia, South America, Africa, Australia, North, America, and Europe.
- The researchers predicted this after accounting for changes in precipitation, humidity, and temperature.
- However, many northern polar regions might see a decrease in wildfires as rainfall is projected to increase while "hot lightning " rates remain constant.
7. Government initiatives to tackle this problem
- Lightning Alert System provides a location-specific forecast of thunder, lightning, strong winds, high winds, and hailstorms occurrences for up to 48 hours.
- The Common Alert Protocol (CAP) system has been released by the National Disaster Management Authority (NDMA) to alert citizens to imminent thunderstorms and lightning.
- From the INSAT-3DR satellite, which uploads data every 15 minutes, ISRO provides information about convective clouds.
- A GPS notification from the Damini App, which was created by the Indian Institute of Tropical Meteorology and Earth System Science organization, alerts users when lightning is nearby and is between 20 to 40 kilometers away.
8. National Oceanic and Atmospheric Administration (NOAA)
The National Oceanic and Atmospheric Administration is an American Scientific and regulatory agency within the United States Department of Commerce that forecasts weather monitors oceanic and atmospheric conditions, chart the seas, conducts deep sea exploration, and manages fishing and protection of marine mammals and endangered species.
NOAA provides services to its customers and information pertaining to the state of the oceans and the atmosphere, such as weather warnings and forecasts via the National Weather Service.
NOAA’s five fundamental activities are
- Monitoring and observing Earth systems with instruments and data collection networks.
- Understanding and describing Earth systems through research and analysis of data.
- Assessing and predicting the changes in these systems over time.
- Engaging, advising, and informing the public and partner organizations with relevant information.
- Custodianship of environmental resources.
Previous year question
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1. During a thunderstorm, the thunder in the skies is produced by the (UPSC 2013)
1. meeting of cumulonimbus clouds in the sky
2. lightning that separates the nimbus clouds
3. violent upward movement of air and water particles
Select the correct answer using the codes given below.
A.1 only B.2 and 3 C.1 and 3 D.None of the above produces the thunder
Answer : D
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For Prelims & Mains
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For Prelims: Lightning, National Oceanic and Atmospheric Administration (NOAA), Common Alert Protocol (CAP) system, National Disaster Management Authority (NDMA), INSAT-3DR satellite, Long continuing current (LOC), and Damini App.
For Mains:1. What is lightning and discuss how does it occur and explain why Hot lighting has more potential of triggering a wildfire than typical lightning?
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Source: The Indian Express
