Cyclones: Meaning, Formation and its Causes
What are Cyclones?
In meteorological terms, a cyclone is a large air mass that rotates around strong center of low atmospheric pressure. In other words, the atmospheric disturbances which involve a closed circulation around a low pressure center, anticlockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere are called as Cyclones. The early or weak phases of a cyclone are called as Tropical Depressions. Cyclones that occur in the Atlantic and North-East Pacific regions are called as hurricanes. Whereas, a cyclone occurring in the North -West Pacific region is called as Typhoons.
How are Cyclones formed?
- Warm and moist air over the ocean rises upwards due to less density, leaving less air near the ocean surface. As a result, it starts to create a low pressure zone.
- Due to the surrounding high -pressure areas, air flows into this low-pressure zone and eventually warms up, forming a cycle.
- With the constant heat rising above warm air and evaporation process, the entire cloud and wind system starts to spin and grow.
- With acquiring more speed, the 'Eye' of the cyclone starts to form in the center.
- This central zone signifies the lowest air pressure air and is calm and clear.
- When the wind's rotating speed reaches 63kmph, it is called a Tropical Storm. However, when the wind speed reaches 119kmph, tropical cyclone formation takes place.
Causes of Cyclones:
- They are caused in areas with low atmospheric pressure.
- Usually, the areas located near the equator face cyclones.
- What causes the cyclones, is the rising of warm air over the ocean surface.
- Coriolis force impacts the area that forms a low pressure zone.
- Atmospheric instability.
- Increased humidity in the lower to middle levels of the troposhere.
- Low vertical wind shear.
- Strong winds cause damages to infrastructure, uproots trees, and lead to other catastrophes.