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

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  • Tropical Cyclones, Hurricanes, and TyphoonsWinds speeds in excess of 64 knots (74 mph)

  • Global sea surface temperaturesT > 81 oF=27 C for hurricane formation

  • Warm enough ocean temperatures & large enough Coriolis force (Latitudes greater than 10 degrees)

  • Stages in development20-34 knots>64 knots35-63 knotsComplexes of thunderstorms

  • stages

  • Tropical DepressionsInitial thunderstorm growth 1. ITCZ

  • Warm enough ocean temperatures & large enough Coriolis force (Latitudes greater than 10 degrees)

  • EyeEye WallRain Bands

  • The pressure in the eye near the surface is very low and controls the hurricanes 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.

    Most Hurricanes are category 1 , 2, or 3. very few are Category 4 or 5.*September is peak hurricane month. The Atlantic hurricane season officially starts June 1 and ends Nov. 30.*Hot Saharan wind blowing off Cape Verde Africa. The associated dust blocks sunlight from getting to the ocean and can decrease the overall intensity of a hurricane season.*Sinking air within the eye results in clear skies.*The eastern Pacific typically has more hurricanes each year than the Atlantic. Few people are affected by Eastern pacific Hurricanes though.*Eastern Pacific has about 60% more storms than the Atlantic.*Eastern Pacific has about 60% more storms than the Atlantic.**August Sept and Oct are big Atlantic Hurricane Months. *The Atlantic has fewer storms during El Nino events. The winds shear in the Atlantic region is typically higher during El Nino events resulting in fewer organized storms.*Red-total hurricanes and tropical storms (named storms)Yellow : total hurricanesGreen : cat 3 or above*

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