AMPHAN, ODISHA, WEST BENGAL!! I’m sure you have been seeing these names on the electronic, social, print media. CYCLONE? YES! Though it is a natural phenomenon, it is justifiable to be dubious on the mechanism of natural phenomena. I am taking you to the mechanism behind the cyclone through this article. Because the mechanism includes technical aspects, the same made me do this in a bit of technical. I’m putting everything in a moderate way and confident that a 2nd read would definitely quench your doubts.

It is never the same mechanism or factors that cause cyclone on every part of the earth. It depends on the atmospheric pressure, the temperature of the ocean/sea, altitudes of mountains, direction of winds, and so on of a particular area. Hitherto, we will be discussing only tropical cyclones.

Why tropical cyclones alone?
It would be helpful to know the physical dimensions of India before we go into the actual topic. India is a country in the tropical region. Earth is spherical shape is divided into two hemispheres by an imaginary line called the equator. They are the Northern hemisphere and the southern hemisphere. India is located in the Northern hemisphere of the earth.

Division of earth:

India is called a tropical region because; Tropic of cancer (23.5 0 ) in the northern hemisphere of the earth divides India into two parts horizontally.

The direction of airflow in the northern hemisphere is from west to east (left to right) and east to west (right to left) in the southern hemisphere. This is called a Coriolis Effect.
Cyclone direction is exactly opposite to that of airflow i.e., in the northern hemisphere they rotate in the counter-clockwise direction and clockwise direction in the southern hemisphere.

How does cyclone occur?
You would be surprised to know that the winds of the Mediterranean Sea will influence the cyclones of India.

The subtropical westerly jet stream is the winds that hail from the Mediterranean Sea. These winds after reaching the region of Punjab, Rajasthan will take two different directions depending on the seasons of India. They flow towards the north of Himalayas in summer and towards the south in winter.

Map for the Mediterranean Sea:

It is important to know about low-pressure areas and high-pressure areas to understand the mechanism. The areas with high temperatures (Hot climate) would mostly be low-pressure areas and with low temperatures (Cold climate) would mostly be high-pressure areas.

For clarification, the areas covered with snow like the Himalayas are high-pressure areas, and areas with deserts/hot climates like Rajasthan, Thar Desert are low-pressure areas.

More obviously, the hot air could be easily escapable into cold air areas. The effect would be more rapid if a wind subjects the displacement of air. The same happens with the subtropical westerly jet stream.

They push the low-pressure air from Rajasthan, Punjab, and parts of other countries flow into the Himalayas and a part of it flows into Bay of Bengal in the east. The high-pressure air from the Himalayas with intense pressure escapes into the Arabian sea of western coast (Gujarat coast, Maharashtra, Goa, Karnataka, Kerala) and they travel to eastern coastal areas (Tamil Nadu, Andhrapradesh, Odisha, WestBengal) and cause cyclones in India.

Why don’t they affect the western coast if they origin in the Arabian Sea?

Cyclones affect mostly on areas with low pressure. The western coast of India has high-pressure areas compared to that of the eastern coast. Another factor that depends is the coastal length of the western coast is very less than that of the eastern coast.

The Western Ghats of India have greater heights and continuous along the coastal line that does not allow the cyclone to hit the western coast. The Eastern coastal length is very broad and with discontinuous Ghats that allows cyclone to enter into coastal areas much rapidly and causes huge destruction. As the eastern coastal areas of India are low-pressured that makes them even more vulnerable to the cyclone.

Regional names of cyclone

  1. Typhoons – China Sea
  2. Tropical Cyclones– Indian Ocean
  3. Hurricanes-Caribbean Sea
  4. Tornadoes-USA
  5. Wily Willies– Northern Australia
  6. Baguio– Philippines
  7. Taifu– Japan

The India Meteorological Department is the nodal agency in India is responsible for meteorological observations, weather forecasting, and seismology. A cyclone in the Bay of Bengal is predicted by the Area Cyclone Warning Centres (ACWC) and in the Arabian Sea is predicted by the Cyclone Warning Centre (CWC). Both ACWC and CWC sent their report to the coordinating center, i.e., National Cyclone Warning Centre (NCWC).

Although Tropical cyclones are known for destruction, when they strike they also bestow certain benefits to the climatic conditions of that area such as relieve drought conditions, Carry heat and energy away from the tropics and transport it towards temperate latitudes, thus helps to maintain equilibrium in the Earth, maintain a relatively stable and warm temperature worldwide.





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