Hurricaneppt - T r opical Cyclones Typhoons, Cycl ones, and...

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Unformatted text preview: T r opical Cyclones Typhoons, Cycl ones, and H ur r i canes T opics D efinitions F or mation Str uctur e M ovement F or ecasting Classification T r ends D amage T opics D efinitions F or mation Str uctur e M ovement F or ecasting Classification T r ends D amage Definitions Tropical Disturbances • Unorganized group of thunderstorms • No rotation Tropical Depressions • At least one closed isobar on a weather map Tropical Storms • Organized storm exhibiting sustained winds Organized >37 mph >37 Hurricanes • Sustained winds >75 mph Typhoons • West Pacific Ocean Cyclones • Southwest Pacific Ocean, Indian Ocean T opics D efinitions F or mation Str uctur e M ovement F or ecasting Classification T r ends D amage Easterly waves Formation Aguado and Burt, Figure 12-9 Formation Hurricanes require deep layers of Hurricanes warm water to form • >81° F and tens of meters thick • Transfer of energy into the storm via Transfer evaporation and condensation evaporation They also depend on: They • Absence of strong vertical wind shear • The coriolis force • Unstable air Unstable Formation Hurricane formation typically restricted to Hurricane 5° - 20 ° N/S 5° Aguado and Burt, Figure 12-2 Formation Formation Formation Formation Formation Formation Formation Human Intervention: Project Stormfury, 19621983 The goal: The Weaken destructiveness of hurrican Weaken by seeding them with silver iodide Challenges: Too little supercooled liquid water Lack of understanding of Lack natural convective cycling natural T opics D efinitions F or mation Str uctur e M ovement F or ecasting Classification T r ends D amage Structure Structure Aguado and Burt, Figure 12-4 Structure Warm-core low Structure Aguado and Burt, Figure 12-5 Structure Structure Aguado and Burt, Figure 12-17 Aguado Structure Aguado and Burt, Figure 12-14 Tornadoes 1948-1972 Movement Structure Eye Summary • Slowing subsiding air, calmer Eye wall • Zone of greatest storm intensity • Some storms develop double­eye walls • Hot towers – localized and more intense areas Spiral rain bands • Multiple convective cells and many thunderstorms • Arranged in “pinwheel formation” T opics D efinitions F or mation Str uctur e M ovement F or ecasting Classification T r ends D amage Movement Limiting factors for movement • Poleward of 20° N/S – not enough Poleward energy energy • Within 5° of equator – not enough Within coriolis effect coriolis Can be erratic and difficult to Can forecast forecast Pressure systems (e.g. Bermuda Pressure high) high) Landfall • Damaging winds and storm surge Movement Movement Aguado and Burt, Figure 12-10 T opics D efinitions F or mation Str uctur e M ovement F or ecasting Classification T r ends D amage F or ecasting F or ecasting F or ecasting F or ecasting F or ecasting F or ecasting T opics D efinitions F or mation Str uctur e M ovement F or ecasting Classification T r ends D amage Classification Class 3 and above are considered intense Class (major) hurricanes (major) Aguado and Burt, Figure 12-10 Classification T opics D efinitions F or mation Str uctur e M ovement F or ecasting Classification T r ends D amage Trends Economic Damage From Pielke et al. (2008) Trends Economic Damage From Pielke et al. (2008) Trends Sea Surface Temperature (SST) Atlantic multidecadal Oscillation Implications of climate change on SST & hurricanes Trends Wind Shear Trends Aguado and Burt, Figure 12-18 T opics D efinitions F or mation Str uctur e M ovement F or ecasting Classification T r ends D amage Damage Two major sources • Wind Debris Tornadoes • Flooding (heavy rains and storm surge) Storm surge • Rise in water level induced by hurricane Piling up of water due to heavy wind drag Low pressure (1 cm rise per 1 mb decrease) Damage Examples Hurricane Katrina, (2005) Hurricane Hugo (1989) Hurricane at Galveston, TX (1900) Katrina http://www.nade.net/_restricted/NADENLFall2005/KatrinaDamage.jpeg Hugo Images from http://www.nationalgeographic.com/forcesofnature Galveston, TX 1900 The deadliest The natural disaster in US history US 6000 fatalities Why so bad? • Powerful Powerful hurricane (~category 4?) (~category • No major No evacuation evacuation Images from • Island city, max Island http://www.ritainfo.com ...
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This note was uploaded on 06/06/2011 for the course GEOG 202 taught by Professor Carborne during the Fall '10 term at South Carolina.

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