“Tropical cyclones originate in the ocean and gradually weaken and terminate as soon as they approach the land. Give grounds for your explanation. (125 Words) [UPPSC 2019]
According to WMO (World Meteorological Organization)- "Cyclone is a low pressure system with sustained winds of atleast 34 knots (63 km/h) and a closed circulation pattern." Favourable conditions for the formation of Tropical Cyclones- High Humidity i.e around 60-80%. Vertical Wind Shear should be lRead more
According to WMO (World Meteorological Organization)- “Cyclone is a low pressure system with sustained winds of atleast 34 knots (63 km/h) and a closed circulation pattern.”
Favourable conditions for the formation of Tropical Cyclones-
- High Humidity i.e around 60-80%.
- Vertical Wind Shear should be low (< 10 m/s).
- Warm Ocean waters with temperature ≥ 26.5 °C .
- Low pressure area.
- Convergence of winds with the upper level of divergence.
- Presence of Coriolis Force.
Differences between Tropical and Temperate Cyclones –
- Origin – Tropical cyclones form only on seas with temperature more than 26.5 °C in between 10° to 30° N and S of the equator ex-Hurricanes whereas Temperate cyclones can be formed both on land as well as seas in between 35° to 65° N and S of equator ex- European Windstorms .
- Shape – Tropical cyclones are elliptical in shape where as Temperate cyclones are in shape of of inverted V .
- Lifespan – Tropical cyclones doesn’t last for more than 1 week whereas Temperate cyclones may last for 2 to 3 weeks .
- Movement – Tropical cyclones move westward then poleward whereas Temperate cyclones move eastward then northeastward.
- Intensity – Tropical cyclones are more intense(Category 1 to 5) as compared to the Temperate cyclones.
Understanding these favourable conditions and differences will help us to predict,prepare and track the movements of cyclones by using effective mitigation strategies like – early warning system,storm shelters, evacuation drills,remote sensing etc .
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1. Loss of Heat Source: Tropical cyclones derive their energy from warm ocean waters. When they move over land, they lose this primary energy source. Evaporation from the ocean, which fuels the cyclone, ceases, leading to a decrease in storm intensity. 2. Increased Friction: On land, cyclones encounRead more
1. Loss of Heat Source: Tropical cyclones derive their energy from warm ocean waters. When they move over land, they lose this primary energy source. Evaporation from the ocean, which fuels the cyclone, ceases, leading to a decrease in storm intensity.
2. Increased Friction: On land, cyclones encounter surface friction from mountains, forests, and buildings. This friction disrupts the cyclone’s circulation and reduces its wind speeds, causing the storm to weaken.
3. Reduced Moisture Supply: Cyclones require high humidity to maintain their structure. Over land, the moisture supply is limited compared to the ocean. As a result, the storm’s convective activity diminishes, leading to weakening.
4. Terrain Disruption: Landforms like mountains can disrupt the storm’s structure by breaking up the wind patterns and rainfall distribution, further contributing to the cyclone’s dissipation.
Recent Example: Cyclone Amphan (2020) weakened as it moved inland after making landfall in West Bengal, illustrating the typical weakening process of tropical cyclones over terrestrial areas.
Conclusion: Tropical cyclones weaken upon reaching land due to the loss of their heat and moisture source, increased friction, and terrain disruptions. These factors contribute to the gradual dissipation of the storm’s intensity.
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