News Highlight
The strongest tropical storm of 2022, dubbed Super Typhoon ‘Hinnamnor’, is making repeated turns in the western Pacific Ocean and is currently making its way back toward the islands of Japan and South Korea, with winds of up to 241 kph.
Key Takeaways
- As of September 1, 2022, the category 5 typhoon — the highest classification on the scale — was about 230 km away from Japan’s Okinawa prefecture.
- One of the factors contributing to the Super Typhoon rapidly intensifying and expanding is the fact that it has started absorbing other local meteorological systems.
- Warm tropical waters and other pre-existing meteorological disturbances have also led to the system’s escalation.
Cyclones
- A cyclone is any large system of winds circling about a centre of low atmospheric pressure.
- Cyclones are usually accompanied by violent storms and bad weather.
- In the Northern Hemisphere, air flows counterclockwise, while in the Southern Hemisphere, it circulates clockwise.
Different Names around the World
Classification of Cyclones
- Cyclones are classified as extratropical cyclones (also called temperate cyclones); and tropical cyclones.
1. Tropical Cyclones
- The term ‘Tropical Cyclone’ is used by the World Meteorological Organisation to describe weather systems with winds greater than ‘Gale Force’ (minimum of 63 km per hour).
- A tropical cyclone is an intense circular storm that originates over warm tropical oceans and is characterised by low atmospheric pressure, high winds, and heavy rain.
- These cyclones are one of the world’s most destructive natural disasters.
- Favourable Conditions for tropical cyclone
- A large sea surface area with a temperature above 27° C.
- Presence of Coriolis force.
- Small differences in the vertical wind speed.
- A pre-existing weak- low-pressure area or low-level-cyclonic circulation.
- Upper divergence above the sea level system.
- Formation
- The development cycle of tropical cyclones may be divided into three stages:
- Formation and Initial Development Stage
- The formation and initial development of a cyclonic storm depend upon various conditions.
- The formation and initial development of cyclone storms rely upon the transfer of water vapour and heat from the warm ocean to the overlying air, primarily through evaporation from the sea surface.
- It encourages the formation of massive vertical cumulus clouds due to the convection with the conduction of rising air above the ocean surface.
- Mature Stage
- In the cyclone maturity stage, the waves that form during the formation stage grow as the warm air replaces the spaces behind the moving cold front, and the organization of both cold and warm fronts increases.
- The cold front in the maturity stage moves much speedily than the warm front, intensifying the circulation of cyclones.
- The system’s lowest pressure is placed at the centre of the wave, and the cyclone’s winds are the strongest about 8 miles above the ground.
- Modification and Decay
- A tropical cyclone begins to weaken concerning its central pressure, internal warmth, and extremely high speed as soon as its source of warm moist air initiates to ebb or abruptly cut off.
- This occurs after its landfall or when it passes over cold water.
2. Extratropical Cyclones
- Mid-latitude depressions, temperate cyclones, frontal depressions, and wave cyclones are all names for extratropical cyclones.
- Both hemispheres are active above the mid-latitudinal zone between 35° and 65° latitude.
- The movement is from west to east, most noticeable during winter.
- Polar and tropical air masses collide and generate fronts in these latitude zones.
- Formation
- The Polar Front theory best explains the formation and evolution of temperate cyclones.
- According to this idea, a polar front is generated when warm-humid air masses from the tropics collide with dry-cold air masses from the poles.
- Because the cold air mass is denser and heavier, the warm air mass is pushed up.
- The contact of cold and warm air masses causes instability, resulting in a drop in pressure at the intersection, particularly in the centre of the interactions.
- As a result of the reduced pressure, a void is generated.
- The surrounding air rushed in to fill the void, and a cyclone formed due to the earth’s rotation.
- Extratropical cyclones contrast with the more violent tropical cyclones or hurricanes, which occur in generally constant temperature zones.
Content Source: Indian Express