Tropical Cyclone Lifecycle and Characteristics

Stages of a Tropical Cyclone

• Origin or Source: Formation begins over large, still, and warm ocean areas.

  • Ocean surface temperature must exceed 26.5°C.
  • Warm air develops above the ocean's surface.
  • Low altitude winds are essential.

• Mature Stage:

  • Warm air rises, carrying moisture and forming clouds in the troposphere (~10 km high).
  • Condensation of moisture releases latent heat, powering the cyclone.
  • Clouds grow up to 12-15 km high.
  • The Coriolis effect causes air to spiral, creating the cyclone's eye and eye wall.
  • Cyclones rotate:
    • Clockwise in the Southern Hemisphere.
    • Anticlockwise in the Northern Hemisphere.
  • Air pressure is lowest at the center (typically 950 millibars or less).

• Dissipation Stage:

  • Occurs after the cyclone loses energy and moisture.
  • Can weaken over land, then re-strengthen over sea.

Formation Conditions

• Ocean Conditions: Requires warm and still ocean surfaces.
• Air Movements: Warm air rises, and cooler winds replace it, creating a cycle.
• Coriolis Effect: Essential for cyclone spiral and eye formation.

Cyclone Characteristics

• Pressure and Wind:

  • Air pressure in cyclones is significantly lower than surrounding air.
  • The difference in pressure leads to strong winds.
  • Example: Typhoon Ida had a pressure of 877 millibars and winds reaching 300 km/h.

• Cyclone Pathway:

  • Driven by global wind circulation.
  • Feeds on warm ocean waters, continuing to grow and move away from its source.

Additional Notes

• Cyclones represent a self-sustaining heat cycle, driven by latent heat release.
• The eye of the storm is calm compared to the surrounding cyclone activity.
• Cyclones can fluctuate in strength during their lifecycle.