Tuesday, November 13, 2012

Hurricanes



Honolulu is an awesome and beautiful place ,but things turn ugly once there are tropical storms like hurricane Iniki.Iniki was a hurricane that hit the islands of Hawaii in September 1992. 


Lets figure out how Hurrican Ikni formed. There had to be a strong Coriolis Effect, which is the rotation of the Earth that causes an interesting phenomena on free moving objects on the Earth. Objects in the Northern Hemisphere are deflected to the right, while objects in the Southern Hemisphere are deflected to the left. The Coriolis Effect thus tries to force winds to shift towards the right or left. A video explaining the effect below.



 Then there needs to be high sea surface temperature, which is the water temperature close to the ocean's surface at least 26 degrees Celsius.

Few changes in wind speed (wind shear) meaning, any change in wind speed or direction along a straight line. In the case of hurricanes, wind shear is important primarily in the vertical direction from the surface to the top of the troposphere. 


They need lots of water vapor which is why they form over the seas. And lastly some convergence to get the hurricane rolling. 

Convergence occurs when air moving from different directions collides. When convergence happens near the surface of the earth, such as when air spirals into the center of a low pressure cell, air is forced upward. 

 This all happened with hurricane Ikini but when the storm grew to a category 4, Hawaii was soon in trouble. So how do hurricanes grow? As evaporation and condensation continue, the air pressure at the surface of the ocean goes down. That lets more water vapor into the air. That vapor rises higher, where it condenses and releases still more energy. The cloud columns grow higher and larger. In this way, a hurricane is a storm that feeds itself. The more it grows, the more energy it releases. The more energy it releases, the more it grows.Below is a video of the storm and its effects. 

Sources:
http://ww2010.atmos.uiuc.edu/%28Gh%29/guides/mtr/hurr/home.rxml

http://www.drgeorgepc.com/HurricaneIniki.html

http://helzhalfacre.com/iniki/

http://usatoday30.usatoday.com/weather/whur7.htm

http://ww2010.atmos.uiuc.edu/%28Gh%29/guides/mtr/hurr/stages/ts.rxml

And my notes =]