What is a tropical cyclone and how does it form? A brief study of the extreme atmospheric phenomenon with an explanation and its main characteristics.
A tropical cyclone (from the Greek kúklos, “circle” ) is a large and violent atmospheric disturbance characterized by a low pressure system that develops over warm tropical or subtropical oceans.
These are extreme weather events associated with strong winds, storm surges and heavy rainfall that can cause severe damage due to their destructive force. The formation of tropical cyclones is fueled by heat and moisture evaporating from the surface of the warm ocean. The moist air rises and condenses, releasing energy in the form of latent heat, which powers the cyclone.
Tropical cyclone: characteristics
The main characteristics that define a tropical cyclone are:
- Central low pressure : At the center of the cyclone there is a very marked low pressure area, which attracts surrounding air. This pressure gradient generates winds that blow toward the center.
- Eye of the cyclone : In the central area of the cyclone there is a relatively calm area called the eye . The air here is descending, with relatively clear skies and no strong winds.
- Eye Wall : A wall of very intense thunderclouds develops around the eye . This area is the most dangerous, with the heaviest rainfall and strongest winds.
- Rotational motion : Tropical cyclones rotate due to the Coriolis force, which is caused by the rotation of the Earth. In the Northern Hemisphere they rotate counterclockwise, while in the Southern Hemisphere they rotate clockwise.
- Heavy Rainfall and Storms : The rains associated with tropical cyclones are very heavy and can cause floods, landslides and other devastating phenomena. In some areas, hundreds of millimetres of rain can fall in just a few hours. In addition, these atmospheric phenomena can lift large masses of ocean water, causing strong storm surges and coastal flooding.
Differences between cyclone, hurricane, storm and tornado
What distinguishes a cyclone from a hurricane , a storm or a tornado? What are the differences? Basically the difference lies mainly in the intensity of the phenomenon and in the terminology used to describe them, depending on the geographical region.
- Storm : This is a more generic term used to describe different weather conditions and phenomena, such as strong winds, heavy rains, not necessarily of tropical origin. In tropical cyclones, tropical storm indicates a phase of intermediate intensity, with winds between 63 and 118 km/h.
- Hurricane : is a tropical cyclone that forms in the Atlantic Ocean or the north-eastern Pacific, to be classified as such it must have winds exceeding 118 km/h. The term hurricane is used mainly in the Atlantic and eastern Pacific regions. They are classified into 5 categories based on wind speed, from Category 1 (winds between 119-153 km/h) to Category 5 (winds exceeding 252 km/h)
- Tornado: A whirlwind (or tornado): is a very intense, swirling column of air that extends from the base of a thundercloud to the Earth’s surface. It is characterized by its violent and concentrated nature. It is generally a smaller phenomenon than a tropical cyclone, but it can have extremely strong winds that make it one of the most destructive meteorological phenomena.
