In News: The strongest tropical storm of 2022, dubbed Super Typhoon ‘Hinnamnor’, has been barrelling across the western Pacific Ocean.
It is presently hurtling back towards the islands of Japan and South Korea, packing wind speeds of upto 241 kilometres per hour.
The category 5 typhoon — the highest classification on the scale — was about 230 km away from Japan’s Okinawa prefecture (islands).
Cyclones
Cyclones are a type of low-pressure environment with rapid inward air circulation.
In the Northern Hemisphere, air flows counter clockwise, while in the Southern Hemisphere, it circulates clockwise.
Tropical Cyclones
The term ‘Tropical Cyclone’ is used by the World Meteorological Organization to describe weather systems with winds greater than ‘Gale Force’ (minimum of 63 km per hour).
Tropical cyclones are formed in the region between the Tropics of Capricorn and Cancer.
They’re large-scale weather systems that form over tropical or subtropical oceans and coalesce into surface wind circulation.
Tropical cyclones are one of the world’s most destructive natural disasters.
Favorable Conditions for the Formation of Tropical Cyclone
A large area of water surface with a temperature above 27° C
The Coriolis force is strong enough to form a cyclonic vortex.
Variations in the vertical wind speed are minor.
A weak low-pressure area or low-level cyclonic circulation already exists.
Above the sea level system, there should be a higher divergence.
Origin of Tropical Cyclones
Tropical cyclones arise over tropical oceans in late summers and have a thermal origin (August to mid-November).
Because of the Coriolis effect, the powerful local convectional currents take on a whirling motion at these regions.
These cyclones form and move until they reach a weak place in the trade wind belt.
Developmental Stages of Tropical Cyclone
Tropical cyclones can be classified into three stages throughout their development:
Formation and Initial Development Stage
The transport of water vapor and heat from the warm ocean to the overlying air, largely through evaporation from the sea surface, is crucial to the creation and early development of a cyclonic storm.
Convection with condensation of rising air above the ocean surface stimulates the creation of huge vertical cumulus clouds.
Mature Stage
The air rises inpowerful thunderstorms as a tropical storm intensifies, and it tends to spread out horizontally at the tropopause level.
When air spreads out, a positive pressure is created at high elevations, speeding up the downward migration of air due to convection.
When subsidence is induced, the air warms up due to compression, resulting in a warm ‘Eye’ (low-pressure center).
A mature tropical cyclone in the Indian Ocean has a concentric pattern of highly turbulent large cumulus thundercloud bands as its principal physical feature.
Modification and Decay
As soon as its source of warm moist air begins to ebb or is abruptly cut off, a tropical cyclone begins to weaken in terms of core low pressure, internal warmth, and extremely fast speeds.
This occurs after it reaches land or passes across chilly water.
Local Names
North Atlantic (including Caribbean and Gulf of Mexico): Hurricanes
Eastern and Central North Pacific: Hurricanes
Western Northern Pacific: Typhoons
Arabian Sea/Northern Indian Ocean: Tropical Cyclones
South Indian Ocean: Tropical Cyclones/Willy-Willy for southwest Australia
