Structure and Features of Tropical Storms:
Formation of tropical storms:
1. Air is heated above the surface of warm, tropical oceans
○ Warm air rises rapidly under the low pressure conditions (near equator)
2. Rising air draws up more air and large volumes of moisture from the oceans → causing strong winds
3. Coriolis effect causes air to spin upwards around a calm, central eye of the storm
4. As air rises → it cools and condenses to form cumulonimbus clouds (flat base) over the ocean
○ Generates torrential rainfall
○ Latent heat is given off when air condenses → powers the storm
5. Surface winds accelerate inwards and upwards to form the storm
6. Cold air sinks in the eye → no cloud
○ Is much drier and calmer
7. Tropical storm travels across ocean in the direction of the prevailing wind
8. When storm meets land it is no longer fuelled by source of moisture/heat from ocean → loses power
Structure and features of tropical storms:
● Tropical storms are 100s of km wide and circular in shape
○ Eye = centre of the storm
■ Up to 50 km across
■ Is caused by descending air
■ Very low pressure, no clouds/rain
○ Eye is surrounded by eye wall → made out of spiralling, rising air
■ Very strong winds → 160 km/hour
■ Storm clouds, torrential rain and low temperatures
○ Edges of storm → wind speed falls , clouds become more scattered and rain becomes less intense
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Coriolis effect and direction:
● Coriolis effect = deflection/ bending of wind due to the rotational spin of Earth
○ Wind blows from areas of high pressure → low pressure
○ They don’t blow in straight lines because of Coriolis effect
○ As Earth rotates it causes wind to bend
■ Earth has a curvature on its surface
● Equator is far wider than the poles
● Earth spins faster at the equator
■ Difference in speed causes wind to bend as it blows across the earth
● Tropical storms travel from east → west due to direction in which Earths spins
○ They spin anticlockwise in the northern hemisphere
○ They spin clockwise in the southern hemisphere
● Once they hit land → they slow down
○ Energy source is lost
○ Friction occurs
● Losing energy causes storm to change direction → direction and speed is unknown on land
● Average tropical storm lasts between 7 – 14 days