Tropical Cyclones

Tropical Cyclones क्या है?

Intense low-pressure systems forming over warm tropical oceans, characterized by strong winds, heavy rainfall, and storm surges. They are known by different names globally, such as hurricanes (Atlantic), typhoons (Pacific), and cyclones (Indian Ocean).

ऐतिहासिक पृष्ठभूमि

Cyclones have always been a natural phenomenon affecting India's coastal regions. Historically, devastating cyclones like the Great Bengal Cyclone (1737) and the Odisha Super Cyclone (1999) have caused immense loss of life and property. The understanding and management of these events have evolved significantly over time, with increasing focus on early warning and mitigation.

मुख्य प्रावधान

9 points

1.
Formation conditions: Warm sea surface temperature (>26.5°C), Coriolis force (not near the equator), pre-existing low-pressure area, low vertical wind shear, and high relative humidity.
2.
Structure: Consists of an 'eye' (calm, clear center), an 'eyewall' (ring of strongest winds and heaviest rainfall), and 'spiral rainbands' extending outwards.
3.
Classification: Categorized based on sustained wind speeds (e.g., Tropical Depression, Tropical Storm, Severe Cyclonic Storm, Very Severe Cyclonic Storm, Extremely Severe Cyclonic Storm).
4.
Impacts: Devastating coastal flooding due to storm surges, widespread wind damage, heavy rainfall leading to inland floods and landslides, and disruption of infrastructure.
5.
Naming System: Names are assigned by Regional Specialized Meteorological Centres (RSMCs) and Tropical Cyclone Warning Centres (TCWCs) following WMO guidelines, using pre-determined lists contributed by member countries.
6.
Global Distribution: Occur in specific basins such as the North Atlantic, Northeast Pacific, Northwest Pacific, North Indian Ocean, Southwest Indian Ocean, and South Pacific.
7.
Seasonality: Each basin has distinct cyclone seasons (e.g., May-June and October-November for the North Indian Ocean).
8.
Role of Climate Change: Studies suggest potential for increased intensity, rapid intensification, and changes in track and frequency in some regions due to global warming.
9.
Forecasting: Advanced satellite technology, radar, and numerical weather prediction models are used for tracking and predicting cyclone paths and intensity.

दृश्य सामग्री

Tropical Cyclone Formation & Intensification Process

A step-by-step flowchart illustrating the key atmospheric and oceanic conditions required for the formation and intensification of a tropical cyclone, as per IMD's understanding.

1.Warm Sea Surface Temperatures (SST > 26.5-27°C, depth > 50m)
2.Low Pressure Area / Pre-existing Disturbance
3.Coriolis Effect (Away from Equator, >5° Latitude)
4.Low Vertical Wind Shear (Uniform wind speed/direction with height)
5.Moist Air & Atmospheric Instability
6.Rising Warm, Moist Air & Condensation (Latent Heat Release)
7.Intensification: Formation of Eye, Eyewall, Spiral Rainbands
8.Tropical Cyclone (Cyclonic Storm to Super Cyclonic Storm)

हालिया विकास

5 विकास

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Increased frequency of 'very severe' and 'extremely severe' cyclones in the Arabian Sea in recent decades.

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More instances of rapid intensification of cyclones, making forecasting challenging.

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Significant improvements in early warning systems and forecast accuracy by agencies like the India Meteorological Department (IMD).

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Growing focus on climate resilience and adaptation measures in coastal regions to mitigate cyclone impacts.

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Enhanced international cooperation in data sharing and research to better understand and predict tropical cyclones.

स्रोत विषय

North Indian Ocean's Storm Cycle: Four Alarming Trends Emerge

Environment & Ecology

UPSC महत्व

Crucial for UPSC GS Paper 1 (Physical Geography, Disaster Geography) and GS Paper 3 (Environment & Ecology, Disaster Management). Questions often cover their formation, characteristics, impacts, and mitigation strategies.