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 formation | A 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 conditions | Warm seas present ripe conditions for the development and strengthening of cyclones and fuel these systems over the water. |
| Effects | As warm air rises and cools, water vapour condenses to form clouds and this can lead to rains. |
| Most vulnerable region | Weather systems formed over the Bay of Bengal in the peak of summer in May are among the strongest in the North Indian Ocean region. |
| Threats | Can 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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