Cyclone Arnab

Syllabus: GS1/Geography

Context

• India’s east coast is bracing for the year’s first cyclone, Cyclone Arnab, which has intensified into a Very Severe Cyclonic Storm over the Bay of Bengal.

About

• The name Arnab was contributed by Bangladesh to the list of names used for tropical cyclones over the North Indian Ocean. It is pronounced “Ornab”. In Bengali, the word Arnab means “ocean” or “sea.”

What are Cyclones?

• The word Cyclone is derived from the Greek word Cyclos, meaning the coils of a snake.
  • It was coined by Henry Peddington because the tropical storms in the Bay of Bengal and the Arabian Sea appear like coiled serpents of the sea.
• Cyclones are powerful, rotating storms that form over warm ocean waters, characterized by low pressure at the center and high winds.

• Worldwide terminology: Cyclones are given many names in different regions of the world:
  • They are known as typhoons in the China Sea and Pacific Ocean; hurricanes in the Caribbean Sea, West Indian islands, and the Atlantic Ocean; tornados in the Guinea lands of West Africa and southern USA; willy-willies in north-western Australia and tropical cyclones in the Indian Ocean. 

How is a Cyclone Formed?

• Conditions: Cyclones typically form over warm ocean waters, the warmth provides the necessary heat and moisture to fuel the cyclone.
• Formation of a Low-Pressure System: When the air rises up and away from the ocean surface, it creates an area of lower air pressure below. 
  • It causes the air from surrounding areas with higher pressure to move towards the low-pressure area which further leads to warming up of the air and causes it to rise above.
• Cyclonic Circulation: The rotation of the Earth (Coriolis effect) causes the rising air to start spinning around the low-pressure center. This spinning motion leads to the development of cyclonic circulation.

• As the wind system rotates with increasing speed, an eye gets formed in the middle.
  • The centre of a cyclone is very calm and clear with very low air pressure. The difference of temperature between the warm, rising and the cooler environment causes the air to rise and become buoyant.
• Dissipation: A cyclone will eventually weaken and dissipate when it moves over cooler waters, encounters dry air, or interacts with land, which disrupts the system’s supply of warm, moist air.

Source: IE