CYCLONES Bianca Ricci, Sol Echandi and Agustina Fernandez 9ºA- 2013
What is a Cyclone? A cyclone is a system of rotating winds over a warm water area, spinning inward to a low pressure center and generally causing stormy weather.
Structure of a Cyclone • EyeThe centre or eye of a tropical cyclone is at the area of lowest pressure and is characterized by little or no wind and often a cloudless sky. In severe cyclones the eye usually shows up as a circular hole in the central cloud mass. • Eye WallSurrounding the eye is a wall of dense convective cloud rising about 15 km into the atmosphere. This is the eye wall and is where the most violent winds and heaviest rainfall occur. • Spiral rain bands
Mayor cyclonic areas in the world • North Atlantic • North-East Pacific • North-Central Pacific • North-West Pacific • North Indian Ocean • South-West Indian Ocean • Australian Region • Southern Pacific
How do cyclones form? • Sea water it’s at its hottest (27º or more). • Air above the sea surface is heated and the warm moist starts to rise. • A deep center of low atmospheric pressure is made while the moist rises. • Warm air spirals upward around the center of the cyclone, called the `eye´. • Very dark and heavy clouds form and precipitate torrential rainfall while in the `eye´ the weather is calm and dry. http://www.youtube.com/watch?v=-AAG4HEsgMQ
Factors • Water temperature at least 27º or more • Down to a depth of at least 160 ft. • Rapid cooling with height • High humidity • Low wind speed difference in a small area
Impacts • A cyclone can be still powerful enough to destroy vehicles, buildings and other structures and objects. • They can even make them fly in the sky, turning loose debris into fatal projectiles. • Cyclones have caused 1.9 million deaths worldwide.