Tropical Cyclones , Hurricanes, and Typhoons
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Tropical Cyclones , Hurricanes, and Typhoons. Winds speeds in excess of 64 knots (74 mph). Global sea surface temperatures. T > 81 o F=27 °C for hurricane formation. Warm enough ocean temperatures & large enough Coriolis force - PowerPoint PPT Presentation
Transcript of Tropical Cyclones , Hurricanes, and Typhoons
Tropical Cyclones, Hurricanes, and Typhoons
Winds speeds in excess of 64 knots (74 mph)
Global sea surface temperatures
T > 81 oF=27 °C for hurricane formation
Warm enough ocean temperatures & large enough Coriolis force (Latitudes greater than 10 degrees)
Stages in development
20-34 knots
>64 knots
35-63 knots
Complexes of thunderstorms
stages
Tropical DepressionsInitial thunderstorm growth 1. ITCZ
Warm enough ocean temperatures & large enough Coriolis force (Latitudes greater than 10 degrees)
Eye
Eye WallRain Bands
The pressure in the eye near the surface is very low and controls the hurricane’s strength. The pressure high above the surface in the eye is High cause air to sink and clouds to dissappear.
Surface pressure is lowest in the eye of a hurricane. Wind speed is maximum in the eye wall and is usually calm in the eye. Intense rain, winds, and possibly tornadoes are most likely in the eye wall.
Katrina August 28, 2005 TRMM (Tropical Rainfall Measuring Mission)
Climatology
El Nino and Hurricanes
Red-total hurricanes and tropical storms (named storms)Yellow : total hurricanesGreen : cat 3 or above
Are hurricanes getting more frequent or more intense?
Total power dissipated by hurricanes PDI seems to be increasing since 1980.
From: http://www.pbs.org/wgbh/nova/earth/stronger-hurricanes.html And http://www.pbs.org/wgbh/nova/sciencenow/3302/07-hott-nf.html
Most recent data.
