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Thermodynamics of Tornadoes and Hurricanes. Daniel Crnkovich 24 November 2009. Tornadoes and Hurricanes. Tornadoes Form over land If a tornado forms over water it becomes a cyclone Damage due to wind Scaled from F0 – F5 (Fujita Scale) Hurricanes Form over water
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Thermodynamics of Tornadoes and Hurricanes Daniel Crnkovich 24 November 2009
Tornadoes and Hurricanes • Tornadoes • Form over land • If a tornado forms over water it becomes a cyclone • Damage due to wind • Scaled from F0 – F5 (Fujita Scale) • Hurricanes • Form over water • Starts a tropical depression or storm • Damage due to water • Scaled from 1 – 5 (Simpson Scale) • Both are hard to predict and cause extensive damage
Causes of Hurricanes and Tornadoes • Coriolis Force • Inertial force of the Earth • Angular Momentum • Air factors • Temperature difference • Pressure difference • Water factors • Temperature difference • Colliding pressure fronts
Hurricanes modeled by the Carnot Cycle Isothermal expansion (3-4) Formation of eye Increase in entropy Driving force of storm Adiabatic expansion (3-4) Air rises to top of eye wall Lower P and T Isothermal compression (4-1) Cloudy air travels to edge of hurricane (about 200 miles) Decrease in entropy Adiabatic compression (1-2) Return to original state Thermodynamics of a Hurricane
Warm and moist air mass Lead eastward-moving cold fronts Common in the spring No thermodynamic model has been found for tornadoes Often influenced by particle charges differences Physics based Thermodynamics of a Tornado
Predicting Hurricanes and Tornadoes • Hurricanes take time to form • Succession of tropical depression, storm, strengthening • Weaken due to land • Once formed, predicting the path can be difficult • Tornadoes form quickly • Super-cell thunderstorms • “Tornado alley” • Warm and moist air masses followed by cold fronts • Future technologies may help in predictions
Questions? Photos courtesy: google.com; NASA; NOAA Sources: NASA; NOAA; auf.asn.au; charles-chandler.org/Geophysics/Tornadoes Full.php