Atmosphere Contents

6. Secondary Circulation

Tropical cyclones are intense low-latitude depression systems which form over oceans

Tropical cyclones are low pressure systems producing intense storms in the tropics which are given local names such as 'Hurricane' in the Caribbean and Gulf of Mexico, 'Typhoon' in the West Pacific and China Sea and 'Cyclone' in the Indian Sea. Tropical cyclones are extremely unpredictable, partly perhaps due to their extreme energy. They produce extremely high winds and the very low pressure at the surface can cause the sea level to rise which may be transmitted outwards as a tidal wave. The rainfall can be in excess of 1000 mm and their effects in terms of damage to life and property can be devastating, particularly where their land fall is on low lying land such as the Bangladeshi coast, and on islands such as the Philippines or Caribbean. In the course of a year there are generally 80 tropical cyclones causing on average 20,000 deaths. Some are exceptionally devastating, such as the 1991 cyclone which killed 209,000 people in Bangladesh.

Tropical cyclones

What are tropical cyclones?