29 Jan 2024 : Daily Answer Writing

Q1) Describe the structure of a tropical cyclone and the conditions that are suitable for its formation. Also discuss the impact of tropical cyclones on human populations and the natural environment.


The tropical cyclones are a large, rotating system of clouds, thunderstorms, and strong winds that forms over warm ocean waters. They are also known as hurricanes, typhoons, or cyclones, depending on the region in which they form.

The structure of a tropical cyclone consists of several well-defined components as discussed below:

  1. Eye: It is the centre of the storm. It is a relatively calm area of typically 20-50 km in diameter. In strong cyclones, there is clear, cloudless sky above the eye.
  2. Eyewall: The eyewall surrounds the eye through a wall of cumulonimbus clouds. It contains the strongest winds, heaviest rain, and the most severe thunderstorms.
  3. Spiral rain bands: These are bands of thunderstorms which emanate outwards from the eyewall. These bands can extend hundreds of kilometres from the centre of the storm.

Following conditions are suitable for the formation of a tropical cyclone:

  1. Tropical cyclones need moist air for their formation.
  2. Low Wind Shear: The difference in wind speed and direction at different altitudes should be minimal to minimize wind shear.
  3. A low-pressure area is needed to start the process of tropical cyclone formation.
  4. The Coriolis effect is necessary for the formation of a tropical cyclone. It causes the winds to rotate around a low-pressure centre. E.g., tropical cyclones do not form over the equator where the Coriolis force is zero.
  5. Warm Ocean Water: Large pool of ocean water with sea surface temperatures above 27°C is well suited as it provides sufficient evaporation.

The impact of tropical cyclones on human populations is as follows:

  1. Loss of life: Storm surge could inundate low-lying areas, which may lead to large-scale displacement and loss of lives especially for vulnerable sections.
  2. Loss of livelihood: There is disruption of agriculture, fishing, tourism etc. and major economic activities as most of the financial centres are situated along the coast.

Fig: Structure of a Tropical Cyclone

  1. Loss of Infrastructure: The strong winds and rain damage buildings, homes, and infrastructure like electricity, telecommunication, roads etc. The cost of rebuilding infrastructure can be substantial.
  2. Pollution: Seawater ingress causes contamination of drinking water through elevated salinity in groundwater and coastal rivers.

The impact of tropical cyclones on the natural environment is as follows:

  1. Loss of Wildlife: Strong winds can destroy nesting sites for birds. Floods can displace wildlife, particularly those that are endangered or threatened. E.g., the Bengal tiger, or Gir lions.
  2. Nutrient cycling: Coastal ecosystems such as mangroves and seagrass beds absorb and recycle nutrients from the surrounding environment. Tropical cyclones can disrupt this cycling process.
  3. Coastal Erosion: The strong winds, rains, and waves generated by a cyclone can cause coastal erosion and flooding. This could damage landscapes such as lagoons, beaches, wetlands, and other natural features.
  4. Loss of Coral reef: Tropical cyclones can cause physical damage to the reef structure, which takes a long-time to recover. This can lead to long-term impacts on the health and biodiversity of coral reef ecosystems as they are critical habitats for a wide range of marine species.

The impact of tropical cyclones on human populations and the natural environment can be severe with long-lasting effects on communities and ecosystems. It is important to have early warning systems and effective disaster management to help mitigate the impact of tropical cyclones.

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