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Insights into Editorial: How tropical cyclones are named

cyclones_names

Introduction:

The India Meteorological Department (IMD) recently released a list of 169 names of future tropical cyclones that would emerge in the Bay of Bengal and the Arabian Sea.

Cyclones that form in every ocean basin across the world are named by the regional specialised meteorological centres (RSMCs) and Tropical Cyclone Warning Centres (TCWCs).

There are six RSMCs in the world, including the India Meteorological Department (IMD), and five TCWCs.

As an RSMC, the IMD names the cyclones developing over the north Indian Ocean, including the Bay of Bengal and Arabian Sea, after following a standard procedure. The IMD is also mandated to issue advisories to 12 other countries in the region on the development of cyclones and storms.

Rapid intensification of tropical cyclones is generally associated with strong warming rate above eye-wall cloud top that extends into the stratosphere, suggesting that stratospheric downdrafts are involved in rapid intensification of tropical cyclones.

Context:

Cyclone Amphan (pronounced Um-Pun) will make landfall as a very severe cyclone between the Sagar islands of West Bengal and the Hatiya islands of Bangladesh on the evening of May 20, 2020, according to the latest information from India Meteorological Department (IMD).

The storm formed over south-east Bay of Bengal on the evening of May 16, as had been forecasted by the IMD.

IMD predicts that it will move north eastwards initially and then curve towards a north westward direction.

Amphan is the second pre-monsoon cyclone to form in the Bay of Bengal in two years. The pre-monsoon period is generally considered to be unsupportive for the formation of tropical cyclones.

Cyclone formation:

Cyclone is the formation of very low-pressure system with very high-speed winds revolving around it.

Factors like wind speed, wind direction, temperature and humidity contribute to the development of cyclones.

Before cloud formation, water takes up heat from the atmosphere to change into vapour. When water vapour changes back to liquid form as raindrops, this heat is released to the atmosphere.

The heat released to the atmosphere warms the air around. The air tends to rise and causes a drop in pressure. More air rushes to the centre of the storm. This cycle is repeated.

Since Hurricanes derive their energy from heated seawater which can be prevented by presence of upper-level-winds that disrupt the storm circulation forcing it to lose its strength.

How naming of cyclones came into existence:

Cyclones were usually not named. The tradition started with hurricanes in the Atlantic Ocean, where tropical storms that reach sustained wind speeds of 39 miles per hour were given names.

The practice of naming storms started in order to help in the quick identification of storms in warning messages because names are presumed to be far easier to remember than numbers and technical terms.

Experience shows that the use of short, distinctive given names in written as well as spoken communications is quicker and less subject to error than the older more cumbersome latitude-longitude identification methods.

Difference between Hurricanes, Cyclones and Typhoons:

Hurricanes, cyclones and typhoons are all tropical storms. They are all the same thing but are given different names depending on where they appear.

When they reach populated areas they usually bring very strong wind and rain which can cause a lot of damage.

Hurricanes are tropical storms that form over the North Atlantic Ocean and Northeast Pacific. Cyclones are formed over the South Pacific and Indian Ocean. Typhoons are formed over the Northwest Pacific Ocean.

Advantages of naming a Tropical Cyclone:

  1. The practice of naming a storm/tropical cyclone would help identify each individual tropical cyclone.
  2. The purpose of the move was also to make it easier for people to easily understand and remember the tropical cyclone/hurricane in a region, thus to facilitate disaster risk awareness, preparedness, management and reduction.
  3. It does not confuse the public when there is more than one tropical cyclone in the same area.
  4. Many agree that appending names to storms makes it easier for the media to report on tropical cyclones, heightens interest in warnings and increases community preparedness.
  5. It’s easier and less confusing to say “Cyclone Titli” than remember the storm’s number or its longitude and latitude.
  6. These advantages are especially important in exchanging detailed storm information between hundreds of widely scattered stations, coastal bases, and ships at sea. The warning of the cyclone can reach a much wider audience in a short span of time.

What cyclone names has India suggested?

The 13 names in the recent list that have been suggested by India include: Gati, Tej, Murasu, Aag, Vyom, Jhar (pronounced Jhor), Probaho, Neer, Prabhanjan, Ghurni, Ambud, Jaladhi and Vega.

Some of the names picked by India were suggested by the general public. An IMD committee is formed to finalise the names before sending it to the PTC.

Next, India’s choice, Gati, will be chosen, and so on. Subsequent cyclones are being named sequentially, column-wise, with each cyclone given the name immediately below that of the previous cyclone.

Once the bottom of the column is reached, the sequence moves to the top of the next column.

Why eastern coast of India is more vulnerable?

In addition to the storms that originate in the southeast Bay of Bengal and the adjoining Andaman Sea, breakaway typhoons over the Northwest Pacific move across the South China Sea into the Bay of Bengal, intensifying into cyclones.

In contrast, Arabian Sea cyclones are mostly their own formations and they also generally move north-west, away from India’s west coast.

Besides, the Arabian Sea is colder than the Bay of Bengal, which inhibits the formation and intensification of the cyclonic system in the former. Warm sea surface temperature is an ideal platform for cyclones.

Indian Ocean region:

World Meteorological Weather Organization and United Nations Economic and Social Commission for Asia Pacific began to name cyclonic storms since 2000.

Cyclonic storms rising in the North Indian Ocean are named by the Indian Meteorological Department.

In the Indian Ocean region 8 countries (India, Pakistan, Sri Lanka, Bangladesh, Maldives, Myanmar, Oman and Thailand) started the process of giving name to cyclonic storms since 2004 on the initiative of India.

All countries contributed a set of names which are assigned sequentially on the basis of the first Alphabet of the member country.

As soon as the cyclone reaches into area of these 8 countries, predefined name is given to this cyclone. These 8 countries have suggested 8 names each.

The naming culture of the cyclones not only recognizes the threat but compels the countries to take necessary precautionary measures to mitigate the damage.

Cyclone “Okhi”, which came in November 2017, was named by Bangladesh, which means “eye” in Bengali language. Recent cyclone Fani or Foni was also named by the Bangladesh. Fani means “hood of a snake”.

Conclusion:

There are some obvious reasons for knowing about cyclones, these include:

Environmentally cyclones can be important to local ecosystems. eg reefs and the distribution of plants and have adapted to them.

Cyclones can have an economic and emotional effect on people and property directly affected. Thousands of people have died or been displaced by them. Hundreds of homes could be destroyed causing millions of dollars’ worth of damage.

Having a better understanding of cyclones can help you better prepare and perhaps minimise or prevent cyclone damage.

 


Insights Current Affairs Analysis (ICAN) by IAS Topper