what is a cyclone ?


what is a cyclone ?; cyclone is the name of a rotating wind.Generally, cyclones are circular and elliptical air disturbances,The direction of the cyclone in the northern hemisphere is anticlockwise and clockwise in the southern hemisphere

what is cyclone ?

  • Cyclone is the name of a rotating wind.
  • These are the centers of the low pressure, around which the concentric, isobaric lines extend.
  • The pressure decreases from the periphery towards the center, resulting in strong winds from the periphery towards the center.
  • Due to the influence of the Corialis force, these winds rotate in a circular manner .
  • The direction of the cyclone in the northern hemisphere is anticlockwise and clockwise in the southern hemisphere.
  • Generally, cyclones are circular and elliptical air disturbances, in which the low pressure is found near the center or center and the pressure increases from the center to the outside. Consequently, from the periphery towards the center, the wind starts moving, whose direction is opposite to the clock needles in the northern hemisphere and D. Is favorable in the hemisphere.

Cyclone Meaning -

  • Strehler defined cyclone as follows
  • "A center with low air pressure in the middle, and the wind direction in the northern hemisphere moves counter-clockwise towards the center and rotates in a circular shape towards the center near the ground."
  • In his book "An Introduction to climate", Trivarthy has written about cyclones "Cyclones are relatively low winds around which concentric equilibrium lines are found near.
  • Berry and Chorley have defined cyclones in their book "Atmosphere, weather & climate" as "A cyclone, or agar pressure, is an area in which there is usually an equilateral line of rotation around a relatively low air pressure."
There are two types of cyclone depending on the region of origin.

1)   Tropical cyclone

  • These are windstorms or storms, which are intense in the tropical and ordinary in other places. They cause abundant rainfall.
  • They have diameter ranging from 50 to 1000 miles and have relatively low air pressure area.
  • They run at speeds ranging from 20 to 30 miles per hour.
  • These include air rotation from 90 to 130 mph.
  • They are called Hurricane in the West Indies and Typhun in China Sea and the Philippines and Tornado in the US and Willie Willies in Australia.

The following are the salient features of these cyclones -


  1. There is a considerable variation in the size of warm cyclonic cyclones. In general, they have a diameter of 80 to 300 km. Happens till. But sometimes they are so small and weak that they have a diameter of 50 km. Less than.
  2. These cyclones move at different speeds. Weak disturbance speed 32 km. Per hour while Hurricanes 120 km. Let's move at the rate of one hour.
  3. 3. These cyclones move faster in oceanic parts, while the continental parts are exhausted before reaching the interior. The coastal areas are affected by them.
  4. Isobar lines are circular, but due to their low number, they are not easily identifiable in weather maps. Due to the pressure gradient in Hurricane, the winds move rapidly towards the center and acquire the storm form.
  5. Like temperate cyclones, they do not have temperature differences, because tropical cyclones do not have atmospheres.
  6. They are not always moving. Sometimes staying in one place for many days provides rain.
  7. Every part of a tropical cyclone receives rainfall.
  8. In general, tropical cyclones move in an east to west direction with trade winds. The excursion direction from the equator to latitudes 15 ° is western, from 15 ° to 30 ° latitudes towards the poles and beyond it becomes western again.
  9. Tropical cyclones usually occur in summers. The possibility of their arrival in winter becomes negligible.
  10. These cyclones are very destructive due to their intense speed and stormy tendency. They cause immense damage and loss of life in coastal areas. In 1970, due to cyclone that came to Bangladesh, millions of people died and millions became homeless.
  11. The height of these cyclones ranges from 10,000 m to 15,000 m above ground level.

 Types of tropical cyclones (Classification of Tropical Cyclones) 

  • There is so much difference in the size, nature and weather effectiveness of tropical cyclones that it is very difficult to divide them into certain classes.In the United States, they are divided into four parts based on intensity.
  1. Tropical disturbance
  2. Tropical depressions
  3. Tropical Storms
  4. Hurricance or Typhoon
In general, warm tropical cyclones are divided into two main and four sub-types based on their intensity and effectiveness.

1. Thunder Cyclone

(i) Thermal disturbances
(ii) Thermal lobes
2. Severe Cyclone
(i) Hurricane or Typhoon
(ii) Tarnedo

1. Thunder Cyclone

  • Tropical disturbance: These cyclones have one or two even pressure lines. Pettersen has called these disturbances Sanimandab Kendra, where winds flow at a low speed. Among them, the velocity of wind is 40 km. Less than an hour and move slowly.

2. Extratropical cyclone or Temperate cyclones

  • It is a low-pressure storm in the middle and high latitudes.
  • Its velocity is from 20 to 30 mph and the winds move spiral.
  • It often causes snow and rain.
  • They extend more than tropical cyclones, due to these cyclones in India

Types of Temperate Cyclones

  • Temperate cyclones originate from convergence of opposites air vents, although some local cyclones arise due to other reasons. Although each cause leads to temperature variation. There are following types of cyclones on this basis.

1. Tropical Cyclone - 

  • Tropical cyclones sometimes come in the last phase of their journey in the westerly winds.
  • As these cyclones move forward, polar airflows are drawn into them, gradually forming air and they are characterized by temperate cyclones.
  • Thus occasional cyclones are formed before the recurrent cyclones are recycled in the belt of westerly winds.

2. Thermal Cyclone

  • They originate from the local heat of the ground.
  • Humfrezs and Brunt sir have used different namakli for these. Brand said that during the summer, in the temperate regions, the heat and heat of the Sun in the inner part of the continents become the centers of low pressure, where the winds from outside run fast and the cyclone originates.
  • The same action occurs during the Dakshinayana of the Sun in the southern hemisphere.In this type of cyclone summer, SW United States, Siberian Atonement, and U.P. Areas originate in Australia etc.
  • Humphries has named these cyclones Insolation Cyclons, and in the winter when the warm ocean is surrounded by cold terrestrial, low pressure centers on the ocean create thermal cyclones.
  • During the winter, cyclones occur in the Arvotsk Sea, Iceland and the Norwegian Sea.

    • cyclone

3. Lee Cyclone -

  • Such cyclones originate on the windward slopes of the mountains.
  • Such cyclones originate in winters in Colorado and Texas, east of the Rakies mountain range.
  • Such cyclones occur more frequently in the Gulf of Geneva, Europe and in the plains of Lambardi.
  • In these cyclones also, the inclusion of polar air causes the formation of clouds.
  • These cyclones cause dense clouds and heavy rainfall and winds also move at a high speed.
Read it  - What is Hurricane ? 
            -   What is Tornado ?
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