Context:

Cyclone Asna has formed over the Kutch coast in Gujarat and adjoining areas of Pakistan, according to the India Meteorological Department (IMD).

More on the news:

• Cyclone Asna is the first cyclonic storm in the Arabian Sea in August since 1976.
• The name "Asna," meaning "the one to be acknowledged or praised," was given by Pakistan.
• According to the IMD, between 1891 and 2023, only three cyclonic storms formed in the Arabian Sea in August: 1976, 1964, and 1944.
• A low-pressure area formed off north Andhra Pradesh and south Odisha in the Bay of Bengal, a precursor to cyclone development.

India Meteorological Department (IMD)

• It is the national meteorological service of India and the principal government agency in all matters relating to meteorology and allied subjects. 
• Headquartered in New Delhi.
• The IMD was established in 1875.

About Cyclones 

• A cyclone is a large system of winds that circulates around a center of low atmospheric pressure, moving in a counterclockwise direction north of the Equator and in a clockwise direction south of the Equator.
• The term "Cyclone" comes from the Greek word "Cyclos," meaning the coils of a snake, and was coined by Henry Peddington because tropical storms in the Bay of Bengal and the Arabian Sea resemble coiled serpents.
• Cyclones are classified into two types: extra-tropical (or temperate) cyclones and tropical cyclones.

Types of Cyclones

Extra-Tropical Cyclones: 

• Also known as temperate cyclones, these occur in temperate zones and high-latitude regions, sometimes originating in the Polar Regions.
• They have cold air at their center and derive energy from the interaction between cold and warm air masses.
• These cyclones are always associated with one or more fronts, which are boundaries between different air masses—warm and cold.
• They can occur over both land and ocean.

Tropical Cyclones: 

• Develop between the Tropics of Capricorn and Cancer over tropical or subtropical waters, where they organize into surface wind circulation.
• They develop only over seas.

Conditions Needed for Tropical Cyclone Formation

• Low Pressure Area: A low-pressure area must be present.
• High Sea Temperatures: Sea temperatures need to be at least 27°C.
• Converging Winds: Winds near the ocean surface must converge, forcing air to rise and form storm clouds.
• Low Wind Shear: Winds should not vary greatly with height, allowing storm clouds to rise vertically.
• Coriolis Force: The cyclone must be far enough from the equator for the Coriolis force to take effect.

Worldwide Terminology:

• Typhoons: China Sea and Pacific Ocean
• Hurricanes: West Indian islands, Caribbean Sea, and Atlantic Ocean
• Tornadoes: Guinea lands of West Africa and southern USA
• Willy-Willies: North-western Australia
• Tropical Cyclones: Indian Ocean