ATM OCN 100 Summer ATM OCN Summer 2002 LECTURE 16 (con’t.) ATMOSPHERIC OPTICAL PHENOMENA A. Introduction B. Nature of Visible Light C. Optical Processes D. Atmospheric Optical Phenomena

ATM OCN 100 Summer Announcements u Homework 5: –Has been posted on the Web at: – –Due this Friday u Homework 4: –Has been graded and available in the front; please retrieve yours (along with previous items) ; –Answers to be posted on the Web at: – u 2 nd Hour Exam: –Is scheduled 1 this Friday (16 Nov. 2001) –A help sheet has been posted at: –

ATM OCN 100 Summer Aurora in Wisconsin [Channel 3 Weather]

ATM OCN 100 Summer Monday night’s auroral oval [Space Environment Center]

ATM OCN 100 Summer Our nighttime planet [NASA-GSFC]

MADISON’S CURRENT WEATHER at 900 AM CST MON NOV Updated twice an hour at :05 and :25 Sky/Weather: MOSUNNY (CLEAR below 12,000 ft., but Broken High level clouds) Temperature: 41 F (5 C) Dew Point: 31 F (0 C) Relative Humidity: 67% Wind: S10 MPH Barometer: 30.41S Wind Chill Temp: 29 F

ATM OCN 100 Summer Last 24 hrs in Madison Example of Cold Air Advection

ATM OCN 100 Summer CURRENT IR

ATM OCN 100 Summer CURRENT VISIBLE

ATM OCN 100 Summer MICHELLE CURRENT WATER VAPOR

ATM OCN 100 Summer Surface Weather Map from Today with Isobars & Fronts

ATM OCN 100 Summer Current Temperatures ( o F) & Isotherms

ATM OCN 100 Summer Current Dewpoints ( o F)

ATM OCN 100 Summer Tomorrow’s 7AM Forecast

ATM OCN 100 Summer Quiz u Why the Fog?

ATM OCN 100 Summer IFR – Instrument Flight Rules Ceiling < 1000 ft or Visibility < 3 miles

ATM OCN 100 Summer Last 24 hrs in Madison

ATM OCN 100 Summer ATM OCN Summer 2002 LECTURE 16 (con’t.) ATMOSPHERIC OPTICAL PHENOMENA A. INTRODUCTION B. NATURE of VISIBLE LIGHT C. OPTICAL PROCESSES D. ATMOSPHERIC PHENOMENA associated with Atmospheric Particles

ATM OCN 100 Summer

20 Track of storm that sunk the Edmund Fitzgerald, 10 Nov From Knox & Ackerman

ATM OCN 100 Summer Comparison between 10 Nov 1975 & 10 Nov 1998 Storms

ATM OCN 100 Summer Surface Weather Map from Today with Isobars & Fronts

ATM OCN 100 Summer

24 Current Temperatures ( o F) & Isotherms

ATM OCN 100 Summer Tomorrow’s 6 AM Forecast

MADISON’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 ( mb)

ATM OCN 100 Summer Last 24 hrs in Madison FOG

ATM OCN 100 Summer Radar estimated storm total precipitation From 5PM Sun to 9 AM Mon (CDT)

ATM OCN 100 Summer CURRENT VISIBLE

ATM OCN 100 Summer CURRENT IR

ATM OCN 100 Summer Yesterday’s High Temperatures ( ° F)

ATM OCN 100 Summer Yesterday’s High Temperatures ( o F) – ( ) Average High Temperatures

ATM OCN 100 Summer Late Sunday Afternoon Temperatures ( o F)

ATM OCN 100 Summer Late Sunday Afternoon Dewpoints ( o F)

ATM OCN 100 Summer Late Sunday Afternoon Apparent Temperatures/Heat Indices ( o F)

ATM OCN 100 Summer Current Surface Weather Map with Isobars (“iso” = equal & “bar” = weight), Fronts and Radar

ATM OCN 100 Summer Current Surface Winds with Streamlines & Isotachs (“iso” = equal & “tach” = speed) L L H H LL H L L H L H H H L LL

ATM OCN 100 Summer Current Temperatures ( o F) – 24 Hrs Ago Cold Advection + Drier Air

ATM OCN 100 Summer Current Temperatures ( ° F) & Isotherms (“iso” = equal +”therm” = temperature)

ATM OCN 100 Summer Current Dewpoints ( o F)

ATM OCN 100 Summer Sample Radiosonde Sites

ATM OCN 100 Summer RAPID CITY

ATM OCN 100 Summer GREEN BAY

ATM OCN 100 Summer IFR – Instrument Flight Rules Red Dots: Ceiling < 1000 ft or Visibility < 3 miles

ATM OCN 100 Summer Current Apparent Temperatures ( o F)

ATM OCN 100 Summer Forecast Heat Indices

ATM OCN 100 Summer Tomorrow AM Forecast Map

ATM OCN 100 Summer

49 Announcements u Homework #3 is returned today Answer Key is posted at u Homework #4 is due Thurs. u 2 nd Hour Exam is scheduled for Thurs. u Study sheet is posted at: u If you have ??, please see me.

ATM OCN 100 Summer ATM OCN Summer 2002 LECTURE 16 ATMOSPHERIC OPTICAL PHENOMENA A. INTRODUCTION –Why do we have red sunsets, white clouds & blue skies? –Where do we look for a rainbow & what does its occurrence signify?

ATM OCN 100 Summer A. Introduction (con’t.) u Definition & Scope –Optics: To be seen u Historical Background

ATM OCN 100 Summer B. NATURE OF VISIBLE LIGHT u The Electromagnetic Spectrum –A review

ATM OCN 100 Summer B. NATURE OF VISIBLE LIGHT (con’t.) u Visible Light, Sunlight & the Electromagnetic Spectrum –I. Newton, sunlight & polychromatic light u Visible Light, Color & Human Visual Perception

ATM OCN 100 Summer C. OPTICAL PROCESSES u Optical Phenomena depends upon Processes affecting sunlight u Review of Optical Processes –Scattering –Reflection –Refraction –Dispersion –Diffraction where...

ATM OCN 100 Summer C. FUNDAMENTAL OPTICAL PROCESSES u Atmospheric Optical Phenomena depends upon Fundamental Optical Processes affecting sunlight u Review of Fundamental Optical Processes – where...

ATM OCN 100 Summer SCATTERING u Redirection of light ray due to suspended particles. u New direction may be in forward or backward direction. u Depends upon relative size of scatterer: –Rayleigh Scatter [small particles] –Mie Scatter [large particles]

ATM OCN 100 Summer

58REFLECTION u Redirection of light ray in backward direction by large surface. u Reflection Relationship Angle of reflection = angle of incidence

ATM OCN 100 Summer Reflection Relationship Angle of reflection = angle of incidence Reflection Relationship Angle of reflection = angle of incidence

ATM OCN 100 Summer REFLECTION (con’t.) u Depends upon reflecting surface: –Smooth surface  Specular Reflection –Rough surface  Diffuse Reflection

ATM OCN 100 Summer Specular and Diffuse Reflection

ATM OCN 100 Summer Comparisons ScatteringReflection Absorption & Emission

ATM OCN 100 Summer REFRACTION u Redirection of light ray within medium due to density differences.

ATM OCN 100 Summer REFRACTION (con’t.) u Depends upon: –density of medium –wavelength of light –incident angle u Relationship (Snell’s Law) Angle of refraction  angle of incidence Angle of refraction  angle of incidence

ATM OCN 100 Summer Refraction (con’t.)

ATM OCN 100 Summer Refraction (con’t.)

ATM OCN 100 Summer DISPERSION u Separation of polychromatic light ray into component colors during passage through a medium.

ATM OCN 100 Summer DISPERSION (con’t.) u Requires concurrent refraction. u Depends upon: –density of medium –wavelength of light

ATM OCN 100 Summer Dispersion

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

ATM OCN 100 Summer DIFFRACTION (con’t.) u Requires small openings or objects. u Produces light and dark bands. u Depends upon wavelength. u Polychromatic light ray may be broken into component colors.

ATM OCN 100 Summer Diffraction

73 Diffraction (con’t.)

ATM OCN 100 Summer D. ATMOSPHERIC OPTICAL PHENOMENA Optical Phenomena associated with: u Small Particles in Atmosphere u Vertical Air Density Gradients u Liquid Water Drops/Droplets in Air u Ice Crystals in Air where...

ATM OCN 100 Summer Optical Phenomena associated with SMALL PARTICLES in ATMOSPHERE (GAS MOLECULES & AEROSOLS) u Blue Skies (Rayleigh Scatter) u White Clouds (Mie Scatter) u Red Sunsets (Rayleigh & Mie Scatter)

ATM OCN 100 Summer Rayleigh & Mie Scattering

ATM OCN 100 Summer Mie Scatter

ATM OCN 100 Summer Earth-Rise over the Moon (Apollo 8 Mission)

ATM OCN 100 Summer Shadows on Lunar Surface Apollo 16

ATM OCN 100 Summer Shadows on Lunar Surface Apollo 17

ATM OCN 100 Summer

82 SUNRISE FROM SPACE From STS-52 (JSC-NASA)

ATM OCN 100 Summer Solar Eclipse

ATM OCN 100 Summer Rayleigh & Mie Scatter

ATM OCN 100 Summer SUNSETS

86 Sunray Paths in the Atmosphere See Fig. 2.8 Moran & Morgan (1997)

ATM OCN 100 Summer Clouds as Scatterers

ATM OCN 100 Summer Sunlight through a Montana Thunderstorm

ATM OCN 100 Summer Red Clouds at Sunset

ATM OCN 100 Summer Mie Scatter Natural Aerosols in Great Smoky Mtn. N.P.

ATM OCN 100 Summer Mie Scatter - Urban Pollution

ATM OCN 100 Summer Mie Scatter - Urban Pollution

ATM OCN 100 Summer Mie Scatter -- Dust from Space

ATM OCN 100 Summer Red Martian Skies (Viking Lander)

ATM OCN 100 Summer Crepuscular Rays

ATM OCN 100 Summer Crepuscular Rays

ATM OCN 100 Summer Diffuse Reflection from snow vs. Specular Reflection Madison skyline from frozen Lake Monona

ATM OCN 100 Summer Optical Phenomena associated with VERTICAL AIR DENSITY GRADIENTS u Apparent Sunsets (Refraction) u Mirages (Refraction) –Superior Mirages –Inferior Mirages

ATM OCN 100 Summer APPARENT SUNRISE/SUNSET

ATM OCN 100 Summer “Red Sails in Sunset” & Mirage

ATM OCN 100 Summer Distorted Sunsets

ATM OCN 100 Summer Distorted Sunsets

ATM OCN 100 Summer Setting Sun

ATM OCN 100 Summer Green Flash

ATM OCN 100 Summer MIRAGES (con’t.) See Fig. 3 pg. 195 Moran & Morgan (1997) Fig. A -- Superior Mirage Fig. B. -- Inferior Mirage

ATM OCN 100 Summer MIRAGES (con’t.) Inferior mirage

ATM OCN 100 Summer Mirage

108Mirage

109 Other Refraction Phenomena u Twinkle, twinkle little star.

ATM OCN 100 Summer Optical Phenomena associated with LIQUID WATER DROPS/DROPLETS in THE ATMOSPHERE u Rainbows (Refraction, dispersion & reflection) u Corona (Diffraction) u Glories (Diffraction & reflection)

ATM OCN 100 Summer Rainbows

112Rainbows

113 Ray path for a Primary Rainbow See Fig Moran & Morgan (1997)

ATM OCN 100 Summer Ray path for a Primary Rainbow See Fig Moran & Morgan (1997)

ATM OCN 100 Summer “Internal Reflection” in Primary Rainbow

ATM OCN 100 Summer Primary Rainbow

ATM OCN 100 Summer Ray path for a Secondary Rainbow See Fig Moran & Morgan (1997)

ATM OCN 100 Summer Primary & Secondary Rainbows

ATM OCN 100 Summer Backyard Rainbows

ATM OCN 100 Summer High Country Rainbows

ATM OCN 100 Summer Rainbows – A pot of Gold?

ATM OCN 100 Summer Rainbows u Where to look u Weather lore –Evening rainbow = fair weather ahead –Morning rainbow = inclement weather –But only in midlatitudes

ATM OCN 100 Summer Corona

124Corona

125 Corona (con’t.)

ATM OCN 100 Summer Corona

127Corona/Iridescence

128Corona/Iridescence

129 Corona u Where to look u Weather lore

ATM OCN 100 Summer Glory

131 Glory

132 Glory?

Optical Phenomena associated with ICE CRYSTALS in THE ATMOSPHERE u Haloes (Refraction & dispersion) u Parhelia (Sun Dogs) (Refraction & dispersion) u Sun Pillars (Reflection)

ATM OCN 100 Summer degree Halo

ATM OCN 100 Summer Degree Halo Phenomena

ATM OCN 100 Summer Ray path for a 22° Halo See Fig Moran & Morgan (1997)

ATM OCN 100 Summer degree Halo

ATM OCN 100 Summer Degree Halo Phenomena

ATM OCN 100 Summer Ray path for a 46° Halo See Fig Moran & Morgan (1997)

ATM OCN 100 Summer Ray path for a 22° Halo See Fig Moran & Morgan (1997)

ATM OCN 100 Summer Ray path for a 46° Halo See Fig Moran & Morgan (1997)

ATM OCN 100 Summer Halo Phenomena

ATM OCN 100 Summer Halo Phenomena

ATM OCN 100 Summer Sun dog

ATM OCN 100 Summer Sun Dog (Parhelion or Parhelia, pl. )

ATM OCN 100 Summer Sun Dog (Parhelion, Parhelia)

ATM OCN 100 Summer Haloes & Sun dogs u Where to look u Weather lore

ATM OCN 100 Summer Sun Pillar

ATM OCN 100 Summer Sun Pillar (from The Weather Doctor)

ATM OCN 100 Summer Sun Pillar (from The Weather Doctor)