Cyclone: UPSC GS - I Notes

A cyclone is any low-pressure area with winds spiralling inwards. Cyclones rotate anti-clockwise in Northern Hemisphere and rotate clockwise in Southern Hemisphere. The process of Cyclone formation and intensification is called Cyclogenesis.

Aspirants would find this topic very helpful in the IAS Exam.

Types of Cyclone

There are various types of cyclones depending on the type of prevailing low-pressure system.

1. Tropical cyclone
2. Extratropical cyclone
3. Tornadoes

Cyclones are not only present on Earth but also spotted on other planets like Mars, Jupiter, and Neptune. The Great Red Spot is the hurricane on Jupiter which is going on from 340 years. Great Black Spot was spotted in the Southern Hemisphere of Neptune.

How is a Cyclone formed?

When it comes to the formation or strengthening of a cyclone, Cyclogenesis plays a crucial role. It is an umbrella term to identify several different processes that result in a cyclone. Tropical cyclones are formed over warm ocean water near the equator. Warm moist air near the surface of the ocean rises upwards. This creates a low-pressure area near the surface. This results in the movement of cooler air from surrounding areas into the low-pressure area. Now even this cool air becomes warm and moist and rises up. The above cycle keeps continuing. The warm moist air which rises up, cools the water in the air, resulting in the formation of clouds. This whole system of clouds and winds spins and grows. This entire cycle continues resulting in a cyclone. When the winds reach a speed of 63 mph, it is called a tropical storm, when the winds reach a speed of 119 kmph it is called a tropical cyclone or hurricane.

Cyclones- UPSC Notes:Download PDF Here

How are Cyclones addressed in Different Locations?

Cyclones are addressed by different names in different locations.

1. Hurricanes – In the Atlantic and Eastern Pacific.
2. Typhoons – In Southeast Asia
3. Cyclone – In the Indian Ocean and Western Pacific around Australia.

Read:

• Cyclone Amphan
• Cyclone Nisarga

How are Cyclones named?

Lists and names of Cyclones are maintained and updated by an international committee of the World Meteorological Organisation (WMO). The original lists had only names of women. In 1979 men’s names were also included. Names of men and women are used alternatively. Six lists are used in rotation. Hence the list used in 2020 will be used again in 2026. If the storms have wreaked havoc on a country, then the names will not be repeated due to reasons of sensitivity. Examples are Katrina in the USA (2005), Sandy in the USA (2012), Haiyan in the Philippines (2013), Irma, and Maria in the Carribean (2017).

Read about Cyclone Disaster Management in the linked article.

Multiple Choice Question

1. Tropical cyclones are compact, circular winds with a diameter of 320km. Its winds swirl around a central region that has low atmospheric pressure. The rotation of the winds is largely driven by the low-pressure centre and by the rotation of the Earth.
2. The ENSO is a recurring climatic pattern involving temperature changes in the waters of the eastern and central tropical Pacific Ocean, and changes in the patterns of upper and lower-level winds, sea level pressure, and tropical rainfall across the Pacific Basin.
3. Regional Specialized Meteorological Centre (RSMC) New Delhi Tropical Cyclone Center is responsible for naming the tropical cyclones that have formed over the Bay of Bengal and the Arabian Sea when they have reached the relevant intensity.
4. The cyclones originating in the Arabian Sea are weaker than those originating from the Bay of Bengal. The formation of weak cyclones in Arabian Sea reasons back to the presence of cold water of the sea.

Choose the correct answer from the below-given options

A) Only Statements 1, 2 and 3 are true

B) Only statements 2, 3 and 4 are true

C) All the above-given statements are true

D) Only statements 1, 3 and 4 are true

Answer: C

The above details would help candidates preparing for UPSC 2023.

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