A thunderstorm, also known as an electrical storm or a lightning storm, is a storm in which lightning strikes and produces a tremendous audible effect in the Earth's atmosphere. Thunderstorms can originate and develop in any geographical region, although they are most common in the mid-latitudes, where warm, moist air from the tropics collides with chilly air from the poles. This article will explain to you about Thunderstorm and Lightning which will be helpful in preparing Geography for the UPSC Civil service exam.

Thunderstorm

• Tornadoes and thunderstorms are strong local storms. They are brief and occur across a tiny region, yet they are violent.
• Thunderstorms are storms that include thunder and lighting, as well as strong rain or hail.
• Thunderstorms are more common on the ground, where temperatures are high. Because of the cold, thunderstorms are less common on aquatic bodies.
• Each year, an estimated 16 million thunderstorms occur worldwide, with approximately 2,000 thunderstorms active at any given time.

Formation of a Thunderstorm

1. Cumulus stage

• Due to solar insolation, the ground is greatly heated.
• Due to the intense lifting of an air parcel, a low pressure begins to form (convention).
• Air from the surrounding area rushes in to fill the void created by the low pressure.
• A towering cumulonimbus cloud forms due to the intense convection of wet hot air.

2. Mature Stage

• Characterized by a strong updraft of rising warm air that causes clouds to develop larger and rise higher.
• Later, a downdraft sends chilly air and rain to Earth.
• A powerful blast of wind signals the arrival of a thunderstorm. This wind is caused by a strong downdraft.
• The route of the thunderstorm is determined by the updraft and downdraft. The course is erratic the majority of the time.

3. Dissipating Stage

• Hails form when clouds reach heights where temperatures are below freezing, and they fall as hailstorms. There is a lot of precipitation.
• The storm subsides in a matter of minutes, and clear weather begins to prevail.

Motion of a Thunderstorm

• A thunderstorm's path is unpredictable. The combination of its updrafts and downdrafts is what causes it to move.
• Isolated storms normally travel at a speed of 20 km (12 miles) per hour, however, some storms travel significantly quicker.
• A supercell storm can travel 65 to 80 kilometres (approximately 40 to 50 miles) per hour in extreme conditions.

What are Downbursts?

• Macrobursts and microbursts are two terms for downdrafts.
• Macroburst has a diameter of more than 4 km and can generate winds of up to 60 metres per second (215 kilometres per hour).

• A microburst is smaller in size, yet it can produce winds of up to 75 metres per second (270 kilometres per hour).
• They pose a major threat to aeroplanes, particularly during takeoff and landing.

Types of Thunderstorms

Based on Origin

1. Convectional Thunderstorms

• It is caused by the intense heating of the ground during summer.
• It is also known as a thermal thunderstorm.

2. Orographic Thunderstorm

• Cumulonimbus clouds form when warm moist air parcels are forced uplifted as they travel over a mountain barrier, bringing heavy precipitation on the windward side.
• In Jammu and Kashmir, Cherrapunji, and Mawsynram, orographic 'Cloud bursts' are widespread.

3. Frontal Thunderstorm

• At cold fronts, the movements of air masses that create thunderstorms are most common.
• The colder, denser air pushes beneath the warm front's warmer air, raising it up.
• Thermal thunderstorms cover a bigger region, whereas frontal thunderstorms are less intense.

Based on Life Span

1. The Single-Cell

• Single-cell thunderstorms are small, weak storms that develop and dissipate in less than an hour.
• On a hot summer afternoon, they are usually driven by heating.
• Single-cell storms can produce torrential rain and lightning for a small period of time (quite prevalent in India during the summer, especially in April and May).
• They're known as 'Mango Showers' in Kerala and 'Blossom Showers' in Karnataka).

2. The Multi-Cell

• A multi-cell thunderstorm is characterised by the formation of additional updrafts along the leading edge of rain-cooled air (the gust front).
• Individual cells have a lifespan of 30 to 60 minutes, although the system as a whole can persist for several hours.
• Hail, severe winds, short tornadoes, and/or flooding are all possible outcomes of multi-cell storms.

3. The Squall Line

• Squall lines are long swaths of thunderstorms that can stretch for hundreds of kilometres.
• These lines are quite common in the Midwest, and they can often be encountered ahead of a strong cold front.
• Heavy rain, hail, lightning, and tornadoes are all possible, but the most dangerous hazard is devastating straight-line winds.
• This can signify strong, damaging winds of up to 70 miles per hour.

4. The Supercell

• A super-cell is a long-lived (greater than 1 hour) and highly organized storm feeding off an updraft (a rising current of air) that is tilted and rotating.
• Most large and violent tornadoes come from supercells.

Lightning and Thunder

• Reduced temperatures cause water vapour to condense as it rises upward in the cumulonimbus cloud.
• The heat generated in the process (the latent heat of condensation) pushes the water molecules upward.
• Water droplets become tiny ice crystals as they approach zero degrees.
• They gain mass as they move higher until they are so heavy that they begin to fall.
• This results in a system in which smaller ice crystals rise and larger crystals fall.
• The resultant collisions cause electrons to be released, in a process comparable to the formation of electric sparks (this is known as ionisation — an electron in the outer shell of the atom is peeled out, and the atom becomes an ion).
• Cation and anion are the two types of ions depending on the charge. Cation: A cation is a positively charged atom or molecule, meaning it has more protons than electrons. An anion is a negatively charged atom or molecule with more electrons than protons.
• As a result of the moving free electrons, there are additional collisions and more electrons, resulting in a chain reaction.
• As a result of the process, the top layer of the cloud becomes positively charged (cations), while the middle layer becomes negatively charged (anions).
• The difference in electrical potential between the two layers is enormous, on the scale of 109 or 1010 volts.
• A massive current on the order of 105 to 106 amperes can be generated in a short period of time.
• It generates heat, which warms the air column between the two layers of cloud.
• The air column appears red during lightning because of this heat.
• Thunder is produced when a hot air column expands and produces shock waves.

Lightning from Cloud to Earth

• Earth is a good electrical conductor, yet it is electrically neutral.
• However, when compared to the cloud's centre layer, it becomes positively charged.
• As a result, a current flow (about 20-15 percent) is directed towards the Earth.
• This current movement is what causes the loss of lives and property.
• Lightning has a higher chance of striking towering objects like trees, towers, or skyscrapers.
• Lightning tends to shift path once it's around 80-100 metres away from the surface, hitting taller objects .

Deadly Strikes

1. Direct Strike:

• This type of attack is most common in open places.

2. Side Flash (Or Side Splash):

• When lightning strikes a taller item, some current jumps to the victim, who then acts as a "short circuit" for the energy.
• When the sufferer is within a foot or two of the impacted object, this usually happens.
• Those seeking refuge under a tree during a rainstorm make up the majority of the victims.

3. Ground current :

• When an object is struck, a large portion of the energy is ejected into and along the ground surface.
• This is known as 'ground current,' and anyone in close proximity can become a victim.
• Ground current has a broader area of effect than other types of current and is responsible for the majority of lightning deaths and injuries.

4. Conduction:

• Lightning can travel large distances in wires or other metals by conduction.
• Conduction is to blame for the majority of indoor lightning deaths and some outdoor deaths.

Features of Lightning

• At both greater and lower altitudes, positive charge accumulates.
• Cloud particles that are larger and heavier have a negative polarity charge.
• Positive polarity clouds particles are smaller and lighter.
• The cloud is responsible for almost two-thirds of all discharges. The rest of the time is spent between the cloud and the ground.

Features of Thunder

• Plasma (ionised gas medium) [30,000 °C] is created by lightning.
• The channel pressure is much higher than the ambient (environmental) pressure, and the channel expands at a rapid rate (speed of sound).
• The resulting shock wave decays swiftly with distance and, after it slows to the speed of sound, is heard as thunder.

Significance

• Thunderstorms aid in the return of negative charges to Earth (lightning is generally negatively charged).
• The earth-atmosphere electrical balance would vanish in 5 minutes if thunderstorms and lightning were not present.
• Chemicals that produce ozone are also produced by lightning.
• They provide water in the summertime, cool the land, and purify the air.
• Lightning helps nourish the soil by balancing the earth's energy.

Conclusion

Plants can grow faster with the help of lightning. Lightning's heat interacts with nitrogen and oxygen in the atmosphere. As a result, nitrates are produced. They fall to the ground as a natural fertiliser when diluted with rain. Lightning also has a major contribution in removing pollutants from the air. By reacting with pollutants like methane, these compounds clear the air. molecules are formed as a result of these processes, which dissolve in water or adhere to surfaces.