Earth as Rotating Spherepeoplebuedupeople on the Web 地球的旋转球peoplebuedu——人们在网上.ppt
Thunderstorms and Tornadoes,Last Lecture:We looked at severe weather events in the lower latitudesPrincipal weather event is the formation and movement of Tropical CyclonesToday:Today we will look at severe weather in the mid-latitudesMost severe weather is related to thunderstormsSignificant convection and precipitationVery strong windsProduces thunder and lightningCan also initiate tornados-most intense wind events on planet,Thunderstorms and Tornadoes,ThunderstormsCells of local,intense convection resulting in the formation of cumulonimbus clouds,heavy rainfall,lightning and occasionally hail and tornados,Thunderstorms and Tornadoes,Air Mass ThunderstormsIsolated storms generated by daytime heating of land surface,Convection Cell,Thunderstorms and Tornadoes,Severe ThunderstormsThunderstorms with high winds,hail and possibly tornados,Thunderstorms and Tornadoes,Mesoscale Convective SystemLong-lived,intense cluster of convection cellsMesoscale Convective ComplexesLarge circular complex of thunderstorms active during the night,Thunderstorms and Tornadoes,Squall lineLine of severe thunderstorms and very strong winds,Thunderstorms and Tornadoes,Dry lineBoundary between hot,dry air and warm,moist air,which tends to form squall line,Thunderstorms and Tornadoes,Lightning electrical discharge producing light from cloud to cloud or cloud to groundThundersound of rapid expansion&cooling of superheated air around a lightning bolt,Thunderstorms and Tornadoes,Charge Separation Difference in charge between cloud top and bottom,Thunderstorms and Tornadoes,Lightning stroke Complex series of processes which produce electrical discharge between cloud and groundLeaderChannel of ionized air along which lightning stroke propagates,Thunderstorms and Tornadoes,TornadoSmall,intense cyclonic storm characterized by a funnel descending from mesocyclone,Thunderstorms and Tornadoes,Tornado Dynamics,Wind Shear,Convection,Thunderstorms and Tornadoes,Tornado Dynamics cont.,Mesocyclone,Tornado,Thunderstorms and Tornadoes,Tornado Structure,Thunderstorms and Tornadoes,Weather Conditions during Formation,Cold front provides Wind Shear,Squall Line provides Convection,Thunderstorms and Tornadoes,“Tornado Alley”Region of the United States with high frequency of tornado occurrence,Thunderstorms and Tornadoes,Fujita ScaleMeasure of strength of tornado based upon severity of damage left behind,Thunderstorms and Tornadoes,Detection of Tornado Vortex Signature using Radar,Hook Echo,
