Introduction:
Tropical cyclones are intense low-pressure systems that develop over warm tropical oceans, characterized by strong winds, heavy rainfall, and storm surges. India is highly vulnerable to cyclones, particularly along its eastern coastline.
Factors Responsible for the Formation of Tropical Cyclones
- Warm Ocean Waters: Sea Surface Temperature (SST) above 26.5°C provides the energy required for cyclone formation.
Example: Bay of Bengal during the pre- and post-monsoon seasons. - Low Atmospheric Pressure: Convergence of warm, moist air creates a low-pressure centre.
- High Humidity: Moist air in the middle troposphere fuels cloud formation and latent heat release.
- Coriolis Force: Adequate Coriolis effect (usually beyond 5° latitude) imparts rotational motion to the cyclone.
- Low Vertical Wind Shear: Weak variation in wind speed and direction allows the cyclone to develop vertically.
Why the Eastern Coast is More Vulnerable
- Bay of Bengal Generates More Cyclones: Nearly 75–80% of cyclones affecting India originate in the Bay of Bengal.
- Higher Sea Surface Temperatures: The Bay of Bengal remains warmer for longer periods, favouring cyclogenesis.
- Large Freshwater Inflow: Rivers such as the Ganga and Brahmaputra reduce salinity, keeping surface waters warmer.
- Funnel-Shaped Coastline: The configuration of the Bay of Bengal amplifies storm surges along the eastern coast.
Example: Odisha and West Bengal experience severe storm surges. - Cyclone Tracks: Prevailing atmospheric circulation directs most cyclones towards the eastern coast.
Example: Odisha, Andhra Pradesh, and West Bengal are the most cyclone-prone states.
Conclusion:
Although tropical cyclones are natural atmospheric phenomena, scientific forecasting, resilient infrastructure, and effective disaster management have significantly reduced cyclone-related casualties in India. Strengthening early warning systems and coastal resilience remains crucial in the face of climate change.
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