1. ATM OCN 100 Summer 2002 1 ATM OCN 100 - Summer 2002 LECTURE 16 (con’t.) ATMOSPHERIC OPTICAL PHENOMENA A. Introduction B. Nature of Visible Light C. Optical Processes D. Atmospheric Optical Phenomena

2. ATM OCN 100 Summer 2002 2Announcements u Homework 5: –Has been posted on the Web at: –http://www.aos.wisc.edu/~hopkins/aos100/homework; http://www.aos.wisc.edu/~hopkins/aos100/homework –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: –http://www.aos.wisc.edu/~hopkins/aos100/homework; http://www.aos.wisc.edu/~hopkins/aos100/homework u 2 nd Hour Exam: –Is scheduled 1 this Friday (16 Nov. 2001) –A help sheet has been posted at: –http://www.aos.wisc.edu/~hopkins/aos100/exams. http://www.aos.wisc.edu/~hopkins/aos100/exams

3. ATM OCN 100 Summer 2002 3 Aurora in Wisconsin [Channel 3 Weather]

4. ATM OCN 100 Summer 2002 4 Monday night’s auroral oval [Space Environment Center]

5. ATM OCN 100 Summer 2002 5 Our nighttime planet [NASA-GSFC]

6. MADISON’S CURRENT WEATHER at 900 AM CST MON NOV 12 2001 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

7. ATM OCN 100 Summer 2002 7 Last 24 hrs in Madison Example of Cold Air Advection

8. ATM OCN 100 Summer 2002 8 CURRENT IR

9. ATM OCN 100 Summer 2002 9 CURRENT VISIBLE

10. ATM OCN 100 Summer 2002 10 MICHELLE CURRENT WATER VAPOR

11. ATM OCN 100 Summer 2002 11 Surface Weather Map from Today with Isobars & Fronts

12. ATM OCN 100 Summer 2002 12 Current Temperatures ( o F) & Isotherms

13. ATM OCN 100 Summer 2002 13 Current Dewpoints ( o F)

14. ATM OCN 100 Summer 2002 14 Tomorrow’s 7AM Forecast

15. ATM OCN 100 Summer 2002 15 Quiz u Why the Fog?

16. ATM OCN 100 Summer 2002 16 IFR – Instrument Flight Rules Ceiling < 1000 ft or Visibility < 3 miles

17. ATM OCN 100 Summer 2002 17 Last 24 hrs in Madison

18. ATM OCN 100 Summer 2002 18 ATM OCN 100 - 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

19. ATM OCN 100 Summer 2002 19

20. 20 Track of storm that sunk the Edmund Fitzgerald, 10 Nov. 1975 From Knox & Ackerman

21. ATM OCN 100 Summer 2002 21 Comparison between 10 Nov 1975 & 10 Nov 1998 Storms

22. ATM OCN 100 Summer 2002 22 Surface Weather Map from Today with Isobars & Fronts

23. ATM OCN 100 Summer 2002 23

24. 24 Current Temperatures ( o F) & Isotherms

25. ATM OCN 100 Summer 2002 25 Tomorrow’s 6 AM Forecast

26. 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 (1018.3 mb)

27. ATM OCN 100 Summer 2002 27 Last 24 hrs in Madison FOG

28. ATM OCN 100 Summer 2002 28 Radar estimated storm total precipitation From 5PM Sun to 9 AM Mon (CDT)

29. ATM OCN 100 Summer 2002 29 CURRENT VISIBLE

30. ATM OCN 100 Summer 2002 30 CURRENT IR

31. ATM OCN 100 Summer 2002 31 Yesterday’s High Temperatures ( ° F)

32. ATM OCN 100 Summer 2002 32 Yesterday’s High Temperatures ( o F) – (1961-90) Average High Temperatures

33. ATM OCN 100 Summer 2002 33 Late Sunday Afternoon Temperatures ( o F)

34. ATM OCN 100 Summer 2002 34 Late Sunday Afternoon Dewpoints ( o F)

35. ATM OCN 100 Summer 2002 35 Late Sunday Afternoon Apparent Temperatures/Heat Indices ( o F)

36. ATM OCN 100 Summer 2002 36 Current Surface Weather Map with Isobars (“iso” = equal & “bar” = weight), Fronts and Radar

37. ATM OCN 100 Summer 2002 37 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

38. ATM OCN 100 Summer 2002 38 Current Temperatures ( o F) – 24 Hrs Ago Cold Advection + Drier Air

39. ATM OCN 100 Summer 2002 39 Current Temperatures ( ° F) & Isotherms (“iso” = equal +”therm” = temperature)

40. ATM OCN 100 Summer 2002 40 Current Dewpoints ( o F)

41. ATM OCN 100 Summer 2002 41 Sample Radiosonde Sites

42. ATM OCN 100 Summer 2002 42 RAPID CITY

43. ATM OCN 100 Summer 2002 43 GREEN BAY

44. ATM OCN 100 Summer 2002 44 IFR – Instrument Flight Rules Red Dots: Ceiling < 1000 ft or Visibility < 3 miles

45. ATM OCN 100 Summer 2002 45 Current Apparent Temperatures ( o F)

46. ATM OCN 100 Summer 2002 46 Forecast Heat Indices

47. ATM OCN 100 Summer 2002 47 Tomorrow AM Forecast Map

48. ATM OCN 100 Summer 2002 48

49. 49 Announcements u Homework #3 is returned today Answer Key is posted at http://www.aos.wisc.edu/~hopkins/aos100/homework http://www.aos.wisc.edu/~hopkins/aos100/homework u Homework #4 is due Thurs. u 2 nd Hour Exam is scheduled for Thurs. u Study sheet is posted at: http://www.aos.wisc.edu/~hopkins/aos100/exams http://www.aos.wisc.edu/~hopkins/aos100/exams u If you have ??, please see me.

50. ATM OCN 100 Summer 2002 50 ATM OCN 100 - 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?

51. ATM OCN 100 Summer 2002 51 A. Introduction (con’t.) u Definition & Scope –Optics: To be seen u Historical Background

52. ATM OCN 100 Summer 2002 52 B. NATURE OF VISIBLE LIGHT u The Electromagnetic Spectrum –A review

53. ATM OCN 100 Summer 2002 53 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

54. ATM OCN 100 Summer 2002 54 C. OPTICAL PROCESSES u Optical Phenomena depends upon Processes affecting sunlight u Review of Optical Processes –Scattering –Reflection –Refraction –Dispersion –Diffraction where...

55. ATM OCN 100 Summer 2002 55 C. FUNDAMENTAL OPTICAL PROCESSES u Atmospheric Optical Phenomena depends upon Fundamental Optical Processes affecting sunlight u Review of Fundamental Optical Processes – where...

56. ATM OCN 100 Summer 2002 56 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]

57. ATM OCN 100 Summer 2002 57

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

59. ATM OCN 100 Summer 2002 59 Reflection Relationship Angle of reflection = angle of incidence Reflection Relationship Angle of reflection = angle of incidence

60. ATM OCN 100 Summer 2002 60 REFLECTION (con’t.) u Depends upon reflecting surface: –Smooth surface  Specular Reflection –Rough surface  Diffuse Reflection

61. ATM OCN 100 Summer 2002 61 Specular and Diffuse Reflection

62. ATM OCN 100 Summer 2002 62 Comparisons ScatteringReflection Absorption & Emission

63. ATM OCN 100 Summer 2002 63REFRACTION u Redirection of light ray within medium due to density differences.

64. ATM OCN 100 Summer 2002 64 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

65. ATM OCN 100 Summer 2002 65 Refraction (con’t.)

66. ATM OCN 100 Summer 2002 66 Refraction (con’t.)

67. ATM OCN 100 Summer 2002 67 DISPERSION u Separation of polychromatic light ray into component colors during passage through a medium.

68. ATM OCN 100 Summer 2002 68 DISPERSION (con’t.) u Requires concurrent refraction. u Depends upon: –density of medium –wavelength of light

69. ATM OCN 100 Summer 2002 69Dispersion

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

71. ATM OCN 100 Summer 2002 71 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.

72. ATM OCN 100 Summer 2002 72 Diffraction

73. 73 Diffraction (con’t.)

74. ATM OCN 100 Summer 2002 74 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...

75. ATM OCN 100 Summer 2002 75 1. 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)

76. ATM OCN 100 Summer 2002 76 Rayleigh & Mie Scattering

77. ATM OCN 100 Summer 2002 77 Mie Scatter

78. ATM OCN 100 Summer 2002 78 Earth-Rise over the Moon (Apollo 8 Mission)

79. ATM OCN 100 Summer 2002 79 Shadows on Lunar Surface Apollo 16

80. ATM OCN 100 Summer 2002 80 Shadows on Lunar Surface Apollo 17

81. ATM OCN 100 Summer 2002 81

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

83. ATM OCN 100 Summer 2002 83 Solar Eclipse

84. ATM OCN 100 Summer 2002 84 Rayleigh & Mie Scatter

85. ATM OCN 100 Summer 2002 85 SUNSETS

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

87. ATM OCN 100 Summer 2002 87 Clouds as Scatterers

88. ATM OCN 100 Summer 2002 88 Sunlight through a Montana Thunderstorm

89. ATM OCN 100 Summer 2002 89 Red Clouds at Sunset

90. ATM OCN 100 Summer 2002 90 Mie Scatter Natural Aerosols in Great Smoky Mtn. N.P.

91. ATM OCN 100 Summer 2002 91 Mie Scatter - Urban Pollution

92. ATM OCN 100 Summer 2002 92 Mie Scatter - Urban Pollution

93. ATM OCN 100 Summer 2002 93 Mie Scatter -- Dust from Space

94. ATM OCN 100 Summer 2002 94 Red Martian Skies (Viking Lander)

95. ATM OCN 100 Summer 2002 95 Crepuscular Rays

96. ATM OCN 100 Summer 2002 96 Crepuscular Rays

97. ATM OCN 100 Summer 2002 97 Diffuse Reflection from snow vs. Specular Reflection Madison skyline from frozen Lake Monona

98. ATM OCN 100 Summer 2002 98 2. Optical Phenomena associated with VERTICAL AIR DENSITY GRADIENTS u Apparent Sunsets (Refraction) u Mirages (Refraction) –Superior Mirages –Inferior Mirages

99. ATM OCN 100 Summer 2002 99 APPARENT SUNRISE/SUNSET

100. ATM OCN 100 Summer 2002 100 “Red Sails in Sunset” & Mirage

101. ATM OCN 100 Summer 2002 101 Distorted Sunsets

102. ATM OCN 100 Summer 2002 102 Distorted Sunsets

103. ATM OCN 100 Summer 2002 103 Setting Sun

104. ATM OCN 100 Summer 2002 104 Green Flash

105. ATM OCN 100 Summer 2002 105 MIRAGES (con’t.) See Fig. 3 pg. 195 Moran & Morgan (1997) Fig. A -- Superior Mirage Fig. B. -- Inferior Mirage

106. ATM OCN 100 Summer 2002 106 MIRAGES (con’t.) Inferior mirage

107. ATM OCN 100 Summer 2002 107 Mirage

108. 108Mirage

109. 109 Other Refraction Phenomena u Twinkle, twinkle little star.

110. ATM OCN 100 Summer 2002 110 3. Optical Phenomena associated with LIQUID WATER DROPS/DROPLETS in THE ATMOSPHERE u Rainbows (Refraction, dispersion & reflection) u Corona (Diffraction) u Glories (Diffraction & reflection)

111. ATM OCN 100 Summer 2002 111 Rainbows

112. 112Rainbows

113. 113 Ray path for a Primary Rainbow See Fig. 8.16 Moran & Morgan (1997)

114. ATM OCN 100 Summer 2002 114 Ray path for a Primary Rainbow See Fig. 8.16 Moran & Morgan (1997)

115. ATM OCN 100 Summer 2002 115 “Internal Reflection” in Primary Rainbow

116. ATM OCN 100 Summer 2002 116 Primary Rainbow

117. ATM OCN 100 Summer 2002 117 Ray path for a Secondary Rainbow See Fig. 8.19 Moran & Morgan (1997)

118. ATM OCN 100 Summer 2002 118 Primary & Secondary Rainbows

119. ATM OCN 100 Summer 2002 119 Backyard Rainbows

120. ATM OCN 100 Summer 2002 120 High Country Rainbows

121. ATM OCN 100 Summer 2002 121 Rainbows – A pot of Gold?

122. ATM OCN 100 Summer 2002 122 Rainbows u Where to look u Weather lore –Evening rainbow = fair weather ahead –Morning rainbow = inclement weather –But only in midlatitudes

123. ATM OCN 100 Summer 2002 123Corona

124. 124Corona

125. 125 Corona (con’t.)

126. ATM OCN 100 Summer 2002 126Corona

127. 127Corona/Iridescence

128. 128Corona/Iridescence

129. 129 Corona u Where to look u Weather lore

130. ATM OCN 100 Summer 2002 130Glory

131. 131 Glory

132. 132 Glory?

133. 133 4. Optical Phenomena associated with ICE CRYSTALS in THE ATMOSPHERE u Haloes (Refraction & dispersion) u Parhelia (Sun Dogs) (Refraction & dispersion) u Sun Pillars (Reflection)

134. ATM OCN 100 Summer 2002 134 22 degree Halo

135. ATM OCN 100 Summer 2002 135 22 Degree Halo Phenomena

136. ATM OCN 100 Summer 2002 136 Ray path for a 22° Halo See Fig. 8.12 Moran & Morgan (1997)

137. ATM OCN 100 Summer 2002 137 46 degree Halo

138. ATM OCN 100 Summer 2002 138 46 Degree Halo Phenomena

139. ATM OCN 100 Summer 2002 139 Ray path for a 46° Halo See Fig. 8.14 Moran & Morgan (1997)

140. ATM OCN 100 Summer 2002 140 Ray path for a 22° Halo See Fig. 8.12 Moran & Morgan (1997)

141. ATM OCN 100 Summer 2002 141 Ray path for a 46° Halo See Fig. 8.14 Moran & Morgan (1997)

142. ATM OCN 100 Summer 2002 142 Halo Phenomena

143. ATM OCN 100 Summer 2002 143 Halo Phenomena

144. ATM OCN 100 Summer 2002 144 Sun dog

145. ATM OCN 100 Summer 2002 145 Sun Dog (Parhelion or Parhelia, pl. )

146. ATM OCN 100 Summer 2002 146 Sun Dog (Parhelion, Parhelia)

147. ATM OCN 100 Summer 2002 147 Haloes & Sun dogs u Where to look u Weather lore

148. ATM OCN 100 Summer 2002 148 Sun Pillar

149. ATM OCN 100 Summer 2002 149 Sun Pillar (from The Weather Doctor)

150. ATM OCN 100 Summer 2002 150 Sun Pillar (from The Weather Doctor)