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Cyclones: How are cyclones formed and named?

GS Paper 1

Syllabus: Important Geophysical Phenomena such as cyclones etc.

 

Source: IE

 

Context: According to the Indian Meteorological Department (IMD), a cyclonic/low-pressure area is developing in the Bay of Bengal and may intensify into a cyclonic storm.

 

What this weather system be called? Cyclone Mocha (pronounced ‘Mokha’) –  a name suggested by Yemen after the Red Sea port city, which is known to have introduced coffee to the world over 500 years ago.

 

What is a cyclone and how are they formed?
Meaning A cyclone is a low-pressure system that forms over warm waters.
Mechanism of formationA high temperature anywhere means the existence of low-pressure air, and a low temperature means high-pressure wind.

 

 

As air warms over hotter regions it ascends, leading to low pressure at the surface it is covering.

 

 

In a depression or low-pressure situation, the air is rising and blows in an anticlockwise direction (in the northern hemisphere) around the low.

 

 

This is because of the Coriolis effect, a result of the earth’s rotation on its axis.

Favourable conditionsWarm seas present ripe conditions for the development and strengthening of cyclones and fuel these systems over the water.
EffectsAs warm air rises and cools, water vapour condenses to form clouds and this can lead to rains.
Most vulnerable regionWeather systems formed over the Bay of Bengal in the peak of summer in May are among the strongest in the North Indian Ocean region.
ThreatsCan lead to individual hazards such as storm surge, flooding, extreme winds, tornadoes and lighting → loss of life and material damage.

How are cyclones named?

  • They are named by the regional specialised meteorological centres (RSMCs) and Tropical Cyclone Warning Centres (TCWCs).
  • There are six RSMCs in the world and five
  • As an RSMC, the IMD names the cyclones developing over the north Indian Ocean, including the Bay of Bengal and the Arabian Sea.
  • The IMD is also mandated to issue advisories to 12 other countries in the region on the development of cyclones and storms.

 

WMO/ESCAP (World Meteorological Organisation/United Nations Economic and Social Commission for Asia and the Pacific):

  • In 2000, the group (comprising Bangladesh, India, the Maldives, Myanmar, Oman, Pakistan, Sri Lanka and Thailand), decided to start naming cyclones in the region.
  • After each country sent in suggestions, the WMO/ESCAP Panel on Tropical Cyclones (PTC) finalised the list.

 

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