Q. Cyclones are one of the most dangerous calamity for tropical regions. Owing to the statement highlight the favourable conditions for formation of such tropical cyclones.
Ans: A cyclone is a low-pressure area where winds converge in a spiraling pattern. In the Northern Hemisphere, cyclones rotate counterclockwise, while in the Southern Hemisphere, they rotate clockwise. The formation and strengthening of a cyclone is known as cyclogenesis.
A recent example of a cyclone is Cyclone Amphan, which formed in the Bay of Bengal in May 2020. It demonstrated the typical anti-clockwise rotation of cyclones in the Northern Hemisphere and significantly impacted parts of India and Bangladesh.
Classification
There are two types of cyclones:
Tropical cyclones; and
Extra Tropical cyclones (also called Temperate cyclones or middle latitude cyclones or Frontal cyclones or Wave Cyclones).
The formation and intensification of tropical cyclones are influenced by several key conditions:
High Sea Surface Temperature: The sea surface temperature must be above 27°C, providing the necessary heat and moisture to fuel the cyclone. For example, the Bay of Bengal often reaches temperatures above 27°C, making it a frequent site for cyclone formation.
Coriolis Force: This force, due to the Earth's rotation, is essential for the cyclone's rotational movement.Cyclone Fani's rotation in 2019 demonstrated the effect of the Coriolis force in the Northern Hemisphere.
Vertical Wind Speed Variation: There should be minimal change in wind speed with height, allowing the cyclone to maintain its structure. Cyclone Nisarga in 2020 maintained its structure partly due to uniform wind speeds at different altitudes.
Pre-existing Low-Pressure Area: A pre-existing low-pressure system or cyclonic circulation provides a foundation for the cyclone to develop. The development of Cyclone Amphan in 2020 was facilitated by an existing low-pressure area in the Bay of Bengal.
Upper-level Divergence: Divergence at higher altitudes above the cyclone helps in drawing air upwards from the lower levels, intensifying the system. The intensification of Cyclone Hudhud in 2014 was aided by significant upper-level divergence.
Way Forward:
Development of Early Warning Systems: Establishing advanced and accurate early warning systems to alert populations about impending cyclones.
Implementation of Mitigation Systems: Adopting comprehensive and well-organized mitigation strategies to minimize damage and loss of life during cyclones.
Conservation of Mangroves: Protecting and expanding mangrove forests, which act as natural barriers, to create buffer zones against the impact of cyclones.
