Week 13 NotesWeek 13 NotesTONIGHT
• Midterm #2 Corrections (HW#11)• Thunderstorms and Tornadoes (Chp 10)• Homework #12 – “Perfect Climate”
Next Week (Apr 28)• Hurricanes (Chp 11)• Air Pollution (chp 12)• Climate Classifications
May 5• Climate Change• TERM PAPERS DUE
May 12• FINAL EXAM• Extra Credit Papers Due
Midterm #2Midterm #2• Class Average = 71 pointsClass Average = 71 points
– Scores adjusted by +4 pointsScores adjusted by +4 points
• pre-Midterm Reviewpre-Midterm Review– w/ review: 77%w/ review: 77%– wo/ review: 61%wo/ review: 61%
• Changing answersChanging answers– About 2/3 of changed answers were wrongAbout 2/3 of changed answers were wrong
Midterm #2 CorrectionsMidterm #2 Corrections• Homework #11 Homework #11 • Same as beforeSame as before
• TYPED (no exceptions)TYPED (no exceptions)• Correct Your Missed QuestionsCorrect Your Missed Questions• Must be 3 part answerMust be 3 part answer
• Correct answerCorrect answer• 1 paragraph (2 or 3 sentences) explaining the 1 paragraph (2 or 3 sentences) explaining the correct answercorrect answer• Source of correct answerSource of correct answer
• DUE AT BEGINNING OF CLASS NEXT WEEK (Apr 28)DUE AT BEGINNING OF CLASS NEXT WEEK (Apr 28)•Well-done complete corrections = 10 points• Points deducted for incomplete or not following directions
Example CorrectionExample CorrectionExample:Example:# 39. C, Scattering# 39. C, Scattering
– The sky is blue because of Rayleigh scattering. The The sky is blue because of Rayleigh scattering. The size of oxygen and nitrogen molecules selectively size of oxygen and nitrogen molecules selectively scatter the shorter blue wavelengths. It is this scatter the shorter blue wavelengths. It is this prominent scattered blue light that our eyes see.prominent scattered blue light that our eyes see.
– Ahrens text: pg 405 (or Atmospheric Optics Ahrens text: pg 405 (or Atmospheric Optics PowerPoint, slide # 62)PowerPoint, slide # 62)
Term PapersTerm Papers(and Extra Credit Term Papers)(and Extra Credit Term Papers)
• 6-10 Pages, typed, double-spaced (exclusive of figures, bibliography)6-10 Pages, typed, double-spaced (exclusive of figures, bibliography)• Scientific Style – Scientific Style – • ABSOLUTELY NO 1ST PERSON. This is a science paper.ABSOLUTELY NO 1ST PERSON. This is a science paper.
• Well-organizedWell-organized• Properly documentedProperly documented• At least 4 CREDIBLE reference sources At least 4 CREDIBLE reference sources (only half may be Internet only source). (only half may be Internet only source). • ABSOLUTELY NO WIKIPEDIA.COMABSOLUTELY NO WIKIPEDIA.COM• References Format: APAReferences Format: APA
http://www.wisc.edu/writetest/Handbook/DocAPA.htmlhttp://www.wisc.edu/writetest/Handbook/DocAPA.html• Grading: Maximum 200 points Grading: Maximum 200 points
Content, Accuracy - 150 points Content, Accuracy - 150 points Organization, Format - 30 pointsOrganization, Format - 30 pointsGrammar, Style - 20 pointsGrammar, Style - 20 points
Thunderstorms and Thunderstorms and TornadoesTornadoes
ThunderstormsThunderstorms• Not RareNot Rare
• 40,000 Times 40,000 Times Each Day Each Day OverOver the Worldthe World• Frequency Is Different but Every Place in the World Frequency Is Different but Every Place in the World has T-stormshas T-storms
• T-storm HazardsT-storm Hazards• LightningLightning• Flash FloodsFlash Floods• HailHail• Winds (Downbursts, Microbursts)Winds (Downbursts, Microbursts)• TornadoesTornadoes• HurricanesHurricanes
Thunderstorm FormationThunderstorm Formation• Warm Humid Rises into an Unstable AtmosphereWarm Humid Rises into an Unstable Atmosphere• Trigger needed to Start LiftTrigger needed to Start Lift
• Unequal heatingUnequal heating• Frontal LiftFrontal Lift• TerrainTerrain
• Enhanced by Strong Diverging Winds AloftEnhanced by Strong Diverging Winds Aloft• CumulonimbusCumulonimbus• TypesTypes
• Ordinary (Air Mass) ThunderstormsOrdinary (Air Mass) Thunderstorms• Severe ThunderstormsSevere Thunderstorms
Air Mass ThunderstormsAir Mass Thunderstorms• Most CommonMost Common
• Least DestructiveLeast Destructive• Limited Life of Less Than an HourLimited Life of Less Than an Hour• LocalizedLocalized
• Life CycleLife Cycle•Cumulus StageCumulus Stage•Mature StageMature Stage•Dissipative StageDissipative Stage
Cumulus StageCumulus Stage• Unstable Air Rises by Localized Unstable Air Rises by Localized Convection Convection • Vertical Motion 10 to 45 mphVertical Motion 10 to 45 mph• Cloud Extends Above Freezing Cloud Extends Above Freezing LevelLevel
• Ice Crystals Form and Grow by Ice Crystals Form and Grow by Bergeron ProcessBergeron Process• Precipitation Begins to FallPrecipitation Begins to Fall
Mature StageMature Stage• Heavy Rain Drags Air forming Heavy Rain Drags Air forming DowndraftsDowndrafts• Downdrafts Strengthened By Downdrafts Strengthened By Cooling From EvaporationCooling From Evaporation• Most Vigorous Rain along edges of Most Vigorous Rain along edges of cloudcloud• Updrafts Dominate Inner Part of Updrafts Dominate Inner Part of CloudCloud
Mature ThunderstormMature Thunderstorm
Dissipating StageDissipating Stage
• As Precipitation and downdrafts As Precipitation and downdrafts dominate then updrafts cut offdominate then updrafts cut off
• Only 20% of Moisture Falls as Only 20% of Moisture Falls as Rain – the Rest EvaporatesRain – the Rest Evaporates
Severe ThunderstormsSevere Thunderstorms• Defined asDefined as
•Wind Speeds Exceed 58 mphWind Speeds Exceed 58 mph
• Hailstones Greater Than ¾” diameterHailstones Greater Than ¾” diameter
• Can Spawn TornadoesCan Spawn Tornadoes
• Extreme Downdrafts and Updrafts Intensify StormExtreme Downdrafts and Updrafts Intensify Storm
• Scale: 6 to 60 mi AcrossScale: 6 to 60 mi AcrossMesoscale Mesoscale
Severe ThunderstormsSevere Thunderstorms• Large Area Allows Several Storms to Cluster (Multi Large Area Allows Several Storms to Cluster (Multi Cell Storms)Cell Storms)
• Mesoscale Convective Systems (Mesoscale Convective Systems (MCSsMCSs))
• Oval Clusters Are Oval Clusters Are Mesoscale Convective Mesoscale Convective Complexes (MCCs) Complexes (MCCs)
• Linear Bands Are Linear Bands Are Squall LinesSquall Lines
• Supercells Supercells Contain a Single Updraft ZoneContain a Single Updraft Zone
• Appear in Isolation or as Part of Appear in Isolation or as Part of MCCsMCCs
• Individual ButIndividual But Storms Develop From A Storms Develop From A Common OriginCommon Origin
Mesoscale Convective Systems (Mesoscale Convective Systems (MCSsMCSs))
• Cover Large Parts of StatesCover Large Parts of States
• Life Span: up to 12 Hours or moreLife Span: up to 12 Hours or more
• Accounts for 60% of All Rain in Middle of US and Accounts for 60% of All Rain in Middle of US and CanadaCanada
• Surrounding Air and Inflow Supports Stronger Winds Surrounding Air and Inflow Supports Stronger Winds and Heavier Precipitationand Heavier Precipitation
Mesoscale Convective Systems (Mesoscale Convective Systems (MCSsMCSs))
• Oval or Roughly CircularOval or Roughly Circular• Organized Systems Containing Numerous ral TstormsOrganized Systems Containing Numerous ral Tstorms• Not All Produce Severe Storms But They Are Self-Not All Produce Severe Storms But They Are Self-PropagatingPropagating• Create Downdrafts That Produce Other CellsCreate Downdrafts That Produce Other Cells• Consider Large Cluster of ThunderstormsConsider Large Cluster of Thunderstorms
• Warm Humid Air at Surface (mT, Wind S)Warm Humid Air at Surface (mT, Wind S)• Dry Air Above (CT, Mexico, Wind SW)Dry Air Above (CT, Mexico, Wind SW)• Wind ShearWind Shear• Downdraft From Other StormsDowndraft From Other Storms• Outflow BoundaryOutflow Boundary
Mesoscale Convective Complexes (Mesoscale Convective Complexes (MCCsMCCs))
Mesoscale Convective Complexes (Mesoscale Convective Complexes (MCCsMCCs))
Squall LinesSquall Lines• Large Number of Individual Storm CellsLarge Number of Individual Storm Cells
• Linear Band ~ 300 mi in LengthLinear Band ~ 300 mi in Length
• Form 60 to 180 mi ahead of Cold FrontForm 60 to 180 mi ahead of Cold Front
Squall LinesSquall Lines
Gusts FrontsGusts Fronts
Gusts FrontGusts Front
Supercell ThunderstormsSupercell Thunderstorms
Supercell ThunderstormsSupercell Thunderstorms
Supercell ThunderstormsSupercell Thunderstorms• Diameter 12 to 30 miDiameter 12 to 30 mi
• Smaller than Squall Smaller than Squall Line or MCCsLine or MCCs
• Most ViolentMost Violent
• Life Span:Life Span:
2 to 4 Hours2 to 4 Hours
Supercell StructureSupercell Structure
Thunderstorm MoistureThunderstorm Moisture
Thunderstorm DistributionThunderstorm Distribution
Avg. Number of Thunderstorm Days per year
Lightning FormationLightning Formation• Excess negative and excess positive charges• Lightning: attempt to equalize electrical differences• Air is a poor conductor, thus electrical potential (charge differences) must be very high before lightning will occur
Lightning FormationLightning Formation• Stepped leader: advancing, branching shaft of negative charges• As stepped leader approaches ground, a spark of positive charges surges upward from the ground• Stepped leader and upward surge create a path for current flow
Lightning FormationLightning Formation• Negative current flows downward from cloud
Lightning FormationLightning Formation• Return stroke: positive current flow upward• Lightning is a sequence of strokes and return strokes• Usually 2-3 strokes; sometimes up to 20 strokes
Lightning CausesLightning Causes• Most Common TheoryMost Common Theory• Collusion of Hail stone Collusion of Hail stone and Ice Crystaland Ice Crystal
• Ice Crystal is Positive Ice Crystal is Positive Charged – Colder Charged – Colder Lighter - Carried to Lighter - Carried to Top of CloudTop of Cloud• Hailstone - Negative Hailstone - Negative Charged - Heavier Charged - Heavier Stays More in Bottom Stays More in Bottom of Cloudof Cloud
Types of LightningTypes of Lightning
Cloud-to-Ground
Cloud-to-Cloud
Within CloudCloud-to-Air
Cloud-to-Ground LightningCloud-to-Ground Lightning
Cloud-to-Ground LightningCloud-to-Ground Lightning
Cloud-to-Ground LightningCloud-to-Ground Lightning
ThunderThunder• Air in Column is Heated to 50,000Air in Column is Heated to 50,000° F° F
• Heated Air Expands ExplosivelyHeated Air Expands Explosively
• Shockwave heard as a Loud NoiseShockwave heard as a Loud Noise
• Speed Difference Flash and SoundSpeed Difference Flash and Sound
• Sounds Travels at 1100 feet per secondSounds Travels at 1100 feet per second
• Light Travels at 186,000 miles per secondLight Travels at 186,000 miles per second
• Each 5 seconds between flash and sound is a mile.Each 5 seconds between flash and sound is a mile.
• Nearby Thunder Is SharpNearby Thunder Is Sharp
• Distant Thunder Echoes and “Rumbles”Distant Thunder Echoes and “Rumbles”
Types of LightningTypes of Lightning• Cloud-to-CloudCloud-to-Cloud
• 80% of All Lightning80% of All Lightning
• Sheet LightningSheet Lightning
• Flash is Obscured by CloudsFlash is Obscured by Clouds
• Sky Lights Up UniformlySky Lights Up Uniformly
• Cloud-to-Ground (Water)Cloud-to-Ground (Water)
• 20%20%
• Negative Charges at Base of CloudNegative Charges at Base of Cloud
Other Lightning TypesOther Lightning Types• Ball LightningBall Lightning
• Appears as a Round, Glowing Mass, Basketball SizeAppears as a Round, Glowing Mass, Basketball Size
• One Form Avoids Electric Conductors and Another is One Form Avoids Electric Conductors and Another is AttractedAttracted
• Saint Elmo’s FireSaint Elmo’s Fire
• Ionization of Air Just Before Cloud-to-ground StrikeIonization of Air Just Before Cloud-to-ground Strike
• Causes Church Steeples and Ship’s Mast to Glow Causes Church Steeples and Ship’s Mast to Glow Green-blue, Giving Out Sparks That HissGreen-blue, Giving Out Sparks That Hiss
Other Lightning TypesOther Lightning Types
Lightning StatisticsLightning Statistics• 12,000 fires/yr in US are started by lightning12,000 fires/yr in US are started by lightning
• 5.2 million acres5.2 million acres• $50 million worth of timber destroyed$50 million worth of timber destroyed
• Total Lightning Losses/ Year: $5 billionTotal Lightning Losses/ Year: $5 billion• Deaths:Deaths:
• Avg =Avg =62/year62/year
• 20082008• 27 killed27 killed• 302 injured302 injured
LightningLightning• Electrical Charge Builds in Air Before Lightning StrikesElectrical Charge Builds in Air Before Lightning Strikes
• If Nothing Else Can be Done Flatten Out on Ground If Nothing Else Can be Done Flatten Out on Ground Get Away From High Points (Trees)Get Away From High Points (Trees)
Lightning SafetyLightning Safety• Lightning can strike up to 15 miles from where it’s Lightning can strike up to 15 miles from where it’s raining raining
• Take cover in a buildingTake cover in a building
• Stay away from electrical appliancesStay away from electrical appliances
• Get Out of the WaterGet Out of the Water
• Stay in the Car Unless It Is a ConvertibleStay in the Car Unless It Is a Convertible
DownburstsDownbursts• DownburstsDownbursts
•Strong Downdrafts up to 165 mphStrong Downdrafts up to 165 mph
• Spread in All Directions to Form Intense Horizontal Spread in All Directions to Form Intense Horizontal WindsWinds
• Damage Sometimes Mistaken for TornadoDamage Sometimes Mistaken for Tornado
• MicroburstMicroburst
• Downburst Less Than 4 km (2.5 mi) in DiameterDownburst Less Than 4 km (2.5 mi) in Diameter
• Airport Danger due to Strong Wind ShearAirport Danger due to Strong Wind Shear
• Headwind for Lift Followed by Tailwind Causing Headwind for Lift Followed by Tailwind Causing Negative LiftNegative Lift
DownburstsDownbursts
Worst Tornado MoviesWorst Tornado Movies• TwisterTwister• Revenge of the TwistersRevenge of the Twisters• Category 7Category 7• Any other movie with a tornado in it … Any other movie with a tornado in it … Except Except
• The Wizard of OzThe Wizard of Oz
TornadoesTornadoes•Extremely Rapid, Rotating WindsExtremely Rapid, Rotating Winds Beneath the Base of Cumulonimbus Beneath the Base of Cumulonimbus CloudsClouds•Most Rotate Cyclonically (CCW NH)Most Rotate Cyclonically (CCW NH)• ShapesShapes
• Some Very Thin rope-shaped Some Very Thin rope-shaped ColumnsColumns• Others Characteristic Funnel Shape Others Characteristic Funnel Shape Smallest at SurfaceSmallest at Surface
• Result From an Extraordinarily Large Result From an Extraordinarily Large Pressure Difference Over a Few Tenths Pressure Difference Over a Few Tenths of a mile (100 mb) of a mile (100 mb)
Tornado CharacteristicsTornado Characteristics• Wide Variety of Shapes and SizesWide Variety of Shapes and Sizes
• Majority Have Diameters = 100 to Majority Have Diameters = 100 to 2000 feet2000 feet
• Time Span a Few Minutes to Several Time Span a Few Minutes to Several HoursHours
• Forward Speed 30mphForward Speed 30mph
• Path of Destruction 2-2.5 miPath of Destruction 2-2.5 mi
• Wind Speed 40 mph to 280 mphWind Speed 40 mph to 280 mph
Tornado PathTornado Path
Tornado FormationTornado Formation• Development Situations
• Frontal Boundaries• Squall Lines• Mesoscale Convective Complexes (MCCs)• Supercells• Tropical Cyclones
• Not Very Well Understood• Most Intense and Destructive Are From Supercells
Tornado DevelopmentTornado Development
• Formation of a Slow Horizontal Rotation of a Large Formation of a Slow Horizontal Rotation of a Large Segment of the CloudSegment of the Cloud
• Up to 12 mi in DiameterUp to 12 mi in Diameter
• Deep in Cloud Several thousand feet in airDeep in Cloud Several thousand feet in air
• Results in Large VorticesResults in Large Vortices
• Mesocyclone Precedes Tornado by ~30 minMesocyclone Precedes Tornado by ~30 min
• Depends on Wind ShearDepends on Wind Shear
• A Rapid Change in Direction Rolling Motion About A Rapid Change in Direction Rolling Motion About Horizontal AxisHorizontal Axis
• Updraft Tilts to Form MesocycloneUpdraft Tilts to Form Mesocyclone
Supercell Tornado DevelopmentSupercell Tornado Development
Supercell Tornado DevelopmentSupercell Tornado Development
Supercell Tornado DevelopmentSupercell Tornado Development
Tornado DamageTornado Damage• Most Damage Is From the High WindsMost Damage Is From the High Winds
• Most Injuries Caused by Flying DebrisMost Injuries Caused by Flying Debris
• Most Violent Tornadoes Have Small Zones of Intense Most Violent Tornadoes Have Small Zones of Intense RotationRotation
• Small High Intensity VorticesSmall High Intensity Vortices
• No suctionNo suction
• Can Destroy One Home Leave Next Door OKCan Destroy One Home Leave Next Door OK
Fujita ScaleFujita Scale
Fujita ScaleFujita ScaleF#F#Wind SpeedWind Speed DamageDamageF0F0 40-72 mph40-72 mph Minor, branches brokenMinor, branches brokenF1F1 72-11272-112 Peels roofs, cars movedPeels roofs, cars movedF2F2 113-157113-157 Roofs torn, boxcars, treesRoofs torn, boxcars, treesF3F3 158-206158-206 Roofs & walls, trainsRoofs & walls, trainsF4F4 207-260207-260 Houses destroyedHouses destroyedF5F5 261-318261-318 Houses lifted, debark treesHouses lifted, debark trees
Tornado DamageTornado DamageF1F172-112 mph 72-112 mph Peels roofs, cars movedPeels roofs, cars moved
F2F2113- 157 mph 113- 157 mph
Roofs torn, boxcars, trees Roofs torn, boxcars, trees
Tornado DamageTornado DamageF3F3158-206 mph158-206 mphRoofs & walls removed, trains Roofs & walls removed, trains movedmoved
F4F4207 - 260 mph 207 - 260 mph
Houses destroyed Houses destroyed
Tornado DamageTornado DamageF5F5261- 318 mph261- 318 mphHouses lifted, debark treesHouses lifted, debark trees
F5 Path of DestructionF5 Path of DestructionLaPlata, MD LaPlata, MD
2002 2002
Enhanced Fujita ScaleEnhanced Fujita Scale
Fujita Scale Enhanced Fujita Scale
F Number3 Second Gust
(mph) EF Number3 Second Gust
(mph)0 45-78 0 65-851 79-117 1 86-1102 118-161 2 111-1353 162-209 3 136-1654 210-261 4 166-200
5 262-317 5 Over 200
• Based on Consistent Assessment of DamageBased on Consistent Assessment of Damage• Enhance description of damage with examples and photos Enhance description of damage with examples and photos that include not only structures, but also vegetationthat include not only structures, but also vegetation• Base damage assignment on more than one structure, if Base damage assignment on more than one structure, if availableavailable
Tornado FrequencyTornado Frequency
Number of tornadoes Avg. Number per 10,000 mi.2
TORNADO TORNADO ALLEYALLEY
Worldwide TornadoesWorldwide Tornadoes
WaterspoutsWaterspouts• WaterspoutsWaterspouts
• Tornadoes Over WaterTornadoes Over Water
• Typically Smaller Diameters and WeakerTypically Smaller Diameters and Weaker
• Some Form Initially Over Water butSome Form Initially Over Water but
• Majority Form Over WaterMajority Form Over Water
• Fair WeatherFair Weather
• Unstable when Warm Water Heats Air From BelowUnstable when Warm Water Heats Air From Below
• Rope-like StructureRope-like Structure
• Water Not Sucked UpWater Not Sucked Up
WaterspoutsWaterspouts
WaterspoutsWaterspouts
HAIL FORMATIONHAIL FORMATION• Particle forms in area Particle forms in area of weak updrafts to of weak updrafts to about 1 mmabout 1 mm• Begins to fallBegins to fall• Swept back up by Swept back up by strong updraftsstrong updrafts• Particles collides with Particles collides with supercooled particles supercooled particles that freeze to itthat freeze to it• Lifting and falling Lifting and falling occur many times occur many times (layers)(layers)• Large enough to fall Large enough to fall or get into downdraft or get into downdraft (entrainment)(entrainment)
HAILHAIL• Spherical or irregular Spherical or irregular chunks of ice greater chunks of ice greater than 5 mm diameterthan 5 mm diameter• Cross-section shows Cross-section shows many layersmany layers• Lethal missilesLethal missiles
•Injure or killInjure or kill•Damage in US Damage in US alone is hundreds of alone is hundreds of millions of dollarsmillions of dollars
Diameter: 140mm (5.5in)Diameter: 140mm (5.5in)Weight 0.75kg(1.7lbs)Weight 0.75kg(1.7lbs)Speed: 45m/s (100mph)Speed: 45m/s (100mph)
HAIL CLIMATOLOGYHAIL CLIMATOLOGY
Avg. Number of Hailstorms per year
Weather HazardsWeather Hazards
Homework #12 - Your Perfect ClimateHomework #12 - Your Perfect Climate
• In a brief paragraph, describe your “perfect” climate and why?In a brief paragraph, describe your “perfect” climate and why?– Hot sunny days? Cool and foggy”Hot sunny days? Cool and foggy”– Rain, Snow?Rain, Snow?– Different seasons?Different seasons?– Weather related activities you enjoy?Weather related activities you enjoy?
• Then find a location (NOT in California) that best fits your idea of Then find a location (NOT in California) that best fits your idea of a perfect climatea perfect climate– Provide details of its average temperatures, rainfall, snow, etc.Provide details of its average temperatures, rainfall, snow, etc.– A good source will be “Climate Charts” in the Week #1 A good source will be “Climate Charts” in the Week #1
Additonal Resources.Additonal Resources.
