Structure, features and the development of tropical storms
In appearance, a tropical storm is like a huge whirlpool - a gigantic mass of revolving moist air.
Tropical storms are between 482-644 kilometres wide and 6-8 kilometres high. They move forward at speeds of 16-24 km/h, but can travel as fast as 65 km/h. The Apparent force, due to the spinning of the Earth, which deflects movement of particles and wind. caused by the rotation of the Earth causes the tropical storm to spin.
The central part of the tropical storm is known as the eye. The eye is usually 32-48 km across. It is an area of light wind speeds and no rain. It contains descending air.
Large towering A type of large, dense, tall, grey cloud which produces rain, hail, or snow. clouds surround the eye. These are caused by warm moist air A change of state in which gas becomes liquid by cooling. as it rises. This leads to very heavy rainfall and wind speeds of up to 320 km/h.
How tropical storms develop
- Tropical storms form between approximately 5掳 and 30掳 latitude. Because of easterly winds they initially move westward.
- The air above the warm ocean is heated. Once the ocean water reaches at least 27掳C, the warm air rises quickly, causing an area of very low pressure.
- As the air continues to rise quickly it draws more warm moist air up from above the ocean leading to strong winds.
- The rapidly rising warm air spirals upwards, cools, condenses and large cumulonimbus clouds form.
- These clouds form the eye wall of the storm and produce heavy rainfall.
- In the centre of the storm, cold air sinks forming the eye of the storm - here, conditions are calm and dry.