What is Tropical Cyclones?
Historical Background
Key Points
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.
Visual Insights
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)
Recent Developments
5 developmentsIncreased frequency of 'very severe' and 'extremely severe' cyclones in the Arabian Sea in recent decades.
More instances of rapid intensification of cyclones, making forecasting challenging.
Significant improvements in early warning systems and forecast accuracy by agencies like the India Meteorological Department (IMD).
Growing focus on climate resilience and adaptation measures in coastal regions to mitigate cyclone impacts.
Enhanced international cooperation in data sharing and research to better understand and predict tropical cyclones.