Tropical Storms

What are tropical storms

Intense low-pressure systems

Types of tropical storms

Typhoons

Hurricanes

Cyclones

Characteristics

Heavy rainfall

High wind speed

High waves

Storm Surges

The Eye

Wind spiralling rapidly around a calm area

Diameter

2000km

Wind speeds

Aren’t constant across the diameter of the storm, they vary with the strongest being towards the eyewall

Distribution of Typhoons

South East of Asia

Distribution of cyclones

East of Africa & South of Asia

Distribution of Hurricane

West of Africa, South East + West of North America, North of South America

Formation of tropical storms; Ocean

Tropical storms gain large amounts of moisture from oceans for the formation of clouds and precipation

Formation of tropical storms; Surface temperatures

Over 27°

Formation of tropical storms; Low wind shear

High wind shear can disrupt the organization and intensity of tropical storms.

Formation of tropical storms; Atmospheric Instability

In tropical regions, warm, moist air near the surface rises, creating instability and promoting the development of storms.

Formation of tropical storms; Coriolis Effect

The rotation of the Earth causes the air to move around the centre of the eye in a circular motion

Degrees of latitude

Form over 5° and 20° north & south of the equator = ocean water warmest temperature and the coriolis effect is the strongest

At the equator (0°-5°)

The Coriolis effect isn’t strong enough

Storms loosing energy

When they reach land/areas of cooler water

High Winds Hazards

Over 119km/h = uprooted trees, damage to infrastructure & buildings, causing loss of life/injury

Intense Rainfall Hazards

flash floods - damage property/injuries from fast moving water

Storm surge

when large volumes of water are forced inwards by low pressure (sea surface rises) and strong winds associated with tropical storms

Storm surge hazards

several metres high = flooding, beach erosion, damaging sea defences & contaminating farmland & freshwater

Coastal & River flooding

Intense rainfall and storm surges = affects to large areas of low lying land - impacts on tourism/farmland

Landslides

Triggered when soil becomes saturated due to intense rainfall = unstable = damage to infrastructure and loss of life

Measurement

Five point Saffir-Simpson scale based on wind speeds

Prediction

Satellites, Weather Balloons. Ocean Buoys

Data for prediction

Atmospheric Pressure, Wind Speed/Direction, Humidity, Sea Surface Temps, Ocean Currents

Use of data collected

Fed into computer models that stimulate atmospheric and ocean behaviour to predict the storm’s path & intensity

Why aren’t predictions accurate

Models although sophisticated still face uncertainties

Why is predicting the storm’s landfall difficult

Storm paths can be erratic = difficulty for precision & accuracy

What does NOAA do each year

releases long term predictions of storm activity for the upcoming season

What are NOAA predictions based on

Historical data, current/predicted climate conditions (ocean temps & atmospheric conditions