MADISON’S CURRENT WEATHERMADISON’S CURRENT WEATHER

Madison Weather at 1000 AM CDT 17 JUL 2002 Updated twice an hour at :05 and :25 Sky/Weather: PTSUNNY Temperature: 79 F (26 C) Dew Point: 65 F (18 C) Relative Humidity: 62% Wind: SW5 MPH Barometer: 30.07F (1018.3 mb)

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 2727

Last 24 hrs in MadisonLast 24 hrs in Madison

                                                                                                                                                    

                

                                                                                                                                                    

                

FOGFOG

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 2828

Radar estimated storm total precipitationRadar estimated storm total precipitation

From 5PM Sun toFrom 5PM Sun to9 AM Mon (CDT)9 AM Mon (CDT)

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 2929

CURRENT CURRENT VISIBLEVISIBLE

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 3030

CURRENT IRCURRENT IR

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 3131

Yesterday’s High Temperatures (Yesterday’s High Temperatures (°°F) F)

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 3232

Yesterday’s High Temperatures (Yesterday’s High Temperatures (ooF) – F) – (1961-90) Average High Temperatures(1961-90) Average High Temperatures

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 3434

Late Sunday Afternoon Late Sunday Afternoon Dewpoints Dewpoints ((ooF) F)

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 3535

Late Sunday Afternoon Late Sunday Afternoon Apparent Temperatures/Heat IndicesApparent Temperatures/Heat Indices ((ooF) F)

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 3636

Current Surface Weather Map Current Surface Weather Map with Isobars (“iso” = equal & “bar” = weight), Fronts and Radarwith Isobars (“iso” = equal & “bar” = weight), Fronts and Radar

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 3939

Current Temperatures (Current Temperatures (°°F) & IsothermsF) & Isotherms(“iso” = equal +”therm” = temperature)(“iso” = equal +”therm” = temperature)

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 4040

Current Dewpoints Current Dewpoints ((ooF) F)

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 4747

Tomorrow AM Forecast MapTomorrow AM Forecast Map

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 4848

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 4949

AnnouncementsAnnouncements

Homework #3 is returned todayHomework #3 is returned todayAnswer Key is posted atAnswer Key is posted athttp://www.aos.wisc.edu/~hopkins/aos100/homeworkhttp://www.aos.wisc.edu/~hopkins/aos100/homework

Homework #4 is due Thurs.Homework #4 is due Thurs. 22ndnd Hour Exam is scheduled for Thurs. Hour Exam is scheduled for Thurs. Study sheet is posted at: Study sheet is posted at: http://www.http://www.aosaos..wiscwisc..

eduedu/~/~hopkinshopkins/aos100/exams/aos100/exams

If you have ??, please see me.If you have ??, please see me.

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 5050

ATM OCN 100 - Summer 2002 ATM OCN 100 - Summer 2002 LECTURE 16LECTURE 16

ATMOSPHERIC OPTICAL ATMOSPHERIC OPTICAL PHENOMENA PHENOMENA

A. INTRODUCTIONA. INTRODUCTION– Why do we have red sunsets, white clouds & Why do we have red sunsets, white clouds &

blue skies?blue skies?– Where do we look for a rainbow & what does its Where do we look for a rainbow & what does its

occurrence signify?occurrence signify?

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 5151

A. Introduction A. Introduction (con’t.)(con’t.)

Definition & ScopeDefinition & Scope

– Optics: To be seenOptics: To be seen Historical BackgroundHistorical Background

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 5252

B. NATURE OF VISIBLE LIGHTB. NATURE OF VISIBLE LIGHT

The Electromagnetic SpectrumThe Electromagnetic Spectrum

– A reviewA review

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 5353

B. NATURE OF VISIBLE LIGHTB. NATURE OF VISIBLE LIGHT (con’t.)(con’t.)

Visible Light, Sunlight Visible Light, Sunlight & the & the

Electromagnetic SpectrumElectromagnetic Spectrum

– I. Newton, sunlight & I. Newton, sunlight & polychromatic light polychromatic light

Visible Light, Color & Visible Light, Color & Human Visual Perception Human Visual Perception

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 5555

C. FUNDAMENTAL OPTICAL PROCESSESC. FUNDAMENTAL OPTICAL PROCESSES

Atmospheric Optical Phenomena Atmospheric Optical Phenomena depends upon Fundamental Optical depends upon Fundamental Optical Processes affecting sunlight Processes affecting sunlight

Review of Fundamental Optical Review of Fundamental Optical ProcessesProcesses– where ...where ...

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 5656

SCATTERINGSCATTERING

Redirection of light ray due to suspended Redirection of light ray due to suspended particles.particles.

New direction may be in forward or backward New direction may be in forward or backward direction.direction.

Depends upon relative size of scatterer:Depends upon relative size of scatterer:

– Rayleigh Scatter Rayleigh Scatter [small particles][small particles]

– Mie Scatter Mie Scatter [large particles][large particles]

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 5757

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 5858

REFLECTIONREFLECTION Redirection of light ray in Redirection of light ray in

backward direction by large surface.backward direction by large surface. Reflection RelationshipReflection Relationship

Angle of reflection = angle of incidenceAngle of reflection = angle of incidence

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 6060

REFLECTION REFLECTION (con’t.)(con’t.) Depends upon reflecting surface:Depends upon reflecting surface:

– Smooth surface Smooth surface Specular Reflection Specular Reflection– Rough surface Rough surface Diffuse Reflection Diffuse Reflection

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 6262

ComparisonsComparisons

ScatteringScattering ReflectionReflectionAbsorption & Absorption &

EmissionEmission

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 6363

REFRACTIONREFRACTION

Redirection of light ray within medium Redirection of light ray within medium due to density differences.due to density differences.

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 6464

REFRACTION REFRACTION (con’t.)(con’t.)

Depends upon:Depends upon:

–density of mediumdensity of medium

–wavelength of lightwavelength of light

– incident angleincident angle RelationshipRelationship (Snell’s Law)(Snell’s Law)

Angle of refraction Angle of refraction angle of incidence angle of incidence

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 6565

RefractionRefraction (con’t.)(con’t.)

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 6666

RefractionRefraction (con’t.)(con’t.)

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 6767

DISPERSIONDISPERSION

Separation of polychromatic light ray into Separation of polychromatic light ray into component colors during passage through a component colors during passage through a medium.medium.

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 6868

DISPERSION DISPERSION (con’t.)(con’t.)

Requires concurrent refraction.Requires concurrent refraction. Depends upon: Depends upon:

– density of mediumdensity of medium

– wavelength of lightwavelength of light

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 6969

DispersionDispersion

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 7070

DIFFRACTIONDIFFRACTION

Constructive & destructive interference patterns of Constructive & destructive interference patterns of light waves due to slight bending of light ray moving light waves due to slight bending of light ray moving around an object.around an object.

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 7171

DIFFRACTIONDIFFRACTION (con’t.)(con’t.)

Requires small openings or objects.Requires small openings or objects. Produces light and dark bands.Produces light and dark bands. Depends upon wavelength.Depends upon wavelength. Polychromatic light ray may be broken into Polychromatic light ray may be broken into

component colors.component colors.

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 7272

DiffractionDiffraction

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 7373

DiffractionDiffraction (con’t.)(con’t.)

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 7474

D. ATMOSPHERIC OPTICAL PHENOMENAD. ATMOSPHERIC OPTICAL PHENOMENA

Optical Phenomena associated with:Optical Phenomena associated with: Small Particles in AtmosphereSmall Particles in Atmosphere Vertical Air Density GradientsVertical Air Density Gradients Liquid Water Drops/Droplets in AirLiquid Water Drops/Droplets in Air Ice Crystals in AirIce Crystals in Air

where ... where ...

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 7575

1. 1. Optical Phenomena associated withOptical Phenomena associated with

SMALL PARTICLES in ATMOSPHERESMALL PARTICLES in ATMOSPHERE(GAS MOLECULES & AEROSOLS)(GAS MOLECULES & AEROSOLS)

Blue SkiesBlue Skies(Rayleigh Scatter)(Rayleigh Scatter)

White CloudsWhite Clouds(Mie Scatter)(Mie Scatter)

Red SunsetsRed Sunsets (Rayleigh & Mie Scatter)(Rayleigh & Mie Scatter)

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 7676

Rayleigh & Mie ScatteringRayleigh & Mie Scattering

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 7777

Mie ScatterMie Scatter

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 7878

Earth-Rise over the Moon Earth-Rise over the Moon (Apollo 8 Mission)(Apollo 8 Mission)

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 8080

Shadows on Lunar SurfaceShadows on Lunar Surface

Apollo 17Apollo 17

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 8181

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 8282

SUNRISE FROM SPACESUNRISE FROM SPACE

From STS-52 (JSC-NASA)From STS-52 (JSC-NASA)

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 8383

Solar EclipseSolar Eclipse

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 8484

Rayleigh & Mie ScatterRayleigh & Mie Scatter

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 8585

SUNSETSSUNSETS

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 8686

Sunray Paths in the AtmosphereSunray Paths in the AtmosphereSee Fig. 2.8 Moran & Morgan (1997)See Fig. 2.8 Moran & Morgan (1997)

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 8787

Clouds as ScatterersClouds as Scatterers

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 8888

Sunlight through a Montana Sunlight through a Montana ThunderstormThunderstorm

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 8989

Red Clouds at SunsetRed Clouds at Sunset

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 9090

Mie Scatter Mie Scatter Natural Aerosols in Great Smoky Mtn. N.P.Natural Aerosols in Great Smoky Mtn. N.P.

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 9191

Mie Scatter - Mie Scatter - Urban PollutionUrban Pollution

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 9292

Mie Scatter - Mie Scatter - Urban PollutionUrban Pollution

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 9393

Mie Scatter -- Mie Scatter -- Dust from SpaceDust from Space

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 9494

Red Martian Skies Red Martian Skies (Viking Lander)(Viking Lander)

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 9595

Crepuscular RaysCrepuscular Rays

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 9696

Crepuscular RaysCrepuscular Rays

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 9797

Diffuse Reflection from snow vs. Diffuse Reflection from snow vs. Specular Reflection Specular Reflection

Madison skyline from frozen Lake MononaMadison skyline from frozen Lake Monona

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 9898

2. 2. Optical Phenomena associated withOptical Phenomena associated with

VERTICAL AIR DENSITY GRADIENTSVERTICAL AIR DENSITY GRADIENTS

Apparent Sunsets Apparent Sunsets (Refraction)(Refraction)

Mirages Mirages (Refraction)(Refraction)

– Superior MiragesSuperior Mirages

– Inferior MiragesInferior Mirages

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 9999

APPARENT SUNRISE/SUNSETAPPARENT SUNRISE/SUNSET

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 100100

““Red Sails in Sunset” & MirageRed Sails in Sunset” & Mirage

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 101101

Distorted SunsetsDistorted Sunsets

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 102102

Distorted SunsetsDistorted Sunsets

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 103103

Setting SunSetting Sun

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 104104

Green FlashGreen Flash

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 105105

MIRAGES MIRAGES (con’t.)(con’t.) See Fig. 3 pg. 195 Moran & Morgan (1997) See Fig. 3 pg. 195 Moran & Morgan (1997)

Fig. A -- Superior Mirage

Fig. B. -- Inferior Mirage

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 106106

MIRAGES MIRAGES (con’t.)(con’t.)Inferior mirageInferior mirage

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 107107

MirageMirage

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 108108

MirageMirage

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 109109

Other Refraction PhenomenaOther Refraction Phenomena

Twinkle, twinkle little star.Twinkle, twinkle little star.

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 110110

3. 3. Optical Phenomena associated withOptical Phenomena associated with

LIQUID WATER DROPS/DROPLETSLIQUID WATER DROPS/DROPLETS in THE ATMOSPHEREin THE ATMOSPHERE

RainbowsRainbows (Refraction, dispersion & reflection)(Refraction, dispersion & reflection)

CoronaCorona (Diffraction)(Diffraction)

GloriesGlories (Diffraction & reflection)(Diffraction & reflection)

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 111111

RainbowsRainbows

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 112112

Rainbows Rainbows

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 114114

Ray path for a Primary RainbowRay path for a Primary Rainbow See Fig. 8.16 Moran & Morgan (1997)See Fig. 8.16 Moran & Morgan (1997)

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 115115

““Internal Reflection” in Primary Internal Reflection” in Primary RainbowRainbow

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 116116

Primary RainbowPrimary Rainbow

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 117117

Ray path for a Secondary RainbowRay path for a Secondary Rainbow See Fig. 8.19 Moran & Morgan (1997)See Fig. 8.19 Moran & Morgan (1997)

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 118118

Primary & Secondary RainbowsPrimary & Secondary Rainbows

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 119119

Backyard RainbowsBackyard Rainbows

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 120120

High Country RainbowsHigh Country Rainbows

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 121121

Rainbows – Rainbows – A pot of Gold?A pot of Gold?

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 122122

RainbowsRainbows

Where to lookWhere to look Weather loreWeather lore

– Evening rainbow = fair weather Evening rainbow = fair weather aheadahead

– Morning rainbow = inclement Morning rainbow = inclement weatherweather

– But only in midlatitudesBut only in midlatitudes

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 123123

CoronaCorona

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 124124

CoronaCorona

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 125125

Corona Corona (con’t.)(con’t.)

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 126126

CoronaCorona

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 127127

Corona/IridescenceCorona/Iridescence

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 128128

Corona/IridescenceCorona/Iridescence

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 129129

CoronaCorona

Where to lookWhere to look Weather loreWeather lore

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 130130

GloryGlory

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 131131

Glory Glory

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 132132

Glory?Glory?

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 133133

4. 4. Optical Phenomena associated withOptical Phenomena associated with

ICE CRYSTALSICE CRYSTALS in THE ATMOSPHEREin THE ATMOSPHERE

HaloesHaloes (Refraction & dispersion)(Refraction & dispersion)

Parhelia (Sun Dogs)Parhelia (Sun Dogs) (Refraction & dispersion)(Refraction & dispersion)

Sun PillarsSun Pillars (Reflection)(Reflection)

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 134134

22 degree Halo22 degree Halo

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 135135

22 Degree Halo Phenomena22 Degree Halo Phenomena

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 136136

Ray path for a Ray path for a 22° Halo22° Halo See Fig. 8.12 Moran & Morgan (1997)See Fig. 8.12 Moran & Morgan (1997)

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 137137

46 degree Halo46 degree Halo

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 138138

46 Degree Halo Phenomena46 Degree Halo Phenomena

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 139139

Ray path for a Ray path for a 46° Halo46° Halo See Fig. 8.14 Moran & Morgan (1997)See Fig. 8.14 Moran & Morgan (1997)

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 142142

Halo PhenomenaHalo Phenomena

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 143143

Halo PhenomenaHalo Phenomena

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 144144

Sun dogSun dog

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 145145

Sun Dog Sun Dog (Parhelion or Parhelia, (Parhelion or Parhelia, pl.pl.))

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 146146

Sun Dog Sun Dog (Parhelion, Parhelia)(Parhelion, Parhelia)

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 147147

Haloes & Sun dogsHaloes & Sun dogs

Where to lookWhere to look Weather loreWeather lore

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 148148

Sun PillarSun Pillar

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 149149

Sun Pillar Sun Pillar (from The Weather Doctor)(from The Weather Doctor)

ATM OCN 100 Summer 2002ATM OCN 100 Summer 2002 150150

Sun Pillar Sun Pillar (from The Weather Doctor)(from The Weather Doctor)