Light, Color,

1
Light, Color, Atmospheric Optics Chapter 15

• ATOC 1050

2
Weather and optical mirages

• Review this overview Mirages A Primer
• Make note of
• Mirage (definition)
• Superior inferior mirage

3
How the Human Eye sees

• Read white colors in your textbook. Have a
  very general understanding of the relationship of
  electromagnetic radiation to the eyes rods
  cones (animation)
• Rods sense brightness
• Cones sense color

4
Reflection Scattering light

• If sunlight is reflected at same angle it strikes
  a surface, then it is reflected.
• That portion of light redirected by various
  molecules and particles in the atmosphere is
  called scattered light.
• No energy is gained or lost due to scattering

5
Question related to text book

• According to our book, what phenomena may cause a
  thunderstorm to appear green?
• (just ref for final exam)

6
Clouds scattering

• Clouds scatter sunlight, which is why they
  normally appear white.
• As clouds near 3300ft in depth, little scattering
  reaches the base of these clouds therefore, the
  clouds appear dark at the bases (bottom of
  clouds)

7
Suns color moon

• When sun is 4 degrees above horizon, its light
  travels through approximately 12 times the amount
  of atmosphere than when overhead.
• At this angle, radiation within the yellow,
  orange, red portion of the spectrum are the
  predominate waves that reach our eyes
• The more scattering by particles, the more red
  a sunrise or sunset
• This is what also causes the Moon to appear
  blue in color lots of particles in atmosphere

8
Optical Terminology

• Transmitted light that passes through a
  substance.
• Refraction light that is bent or redirected at
  a different angle once entering and transmitted
  through a substance.
• Scintillation varying refraction of a point of
  light (star light for example), as it is
  transmitted through various air densities in the
  atmosphere.

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Twilight

• Refraction and subsequent scattering, on clear
  days, causes twilight
• About 30 extra minutes of light during sunrise
  sunset
• green flash

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Halos

• Halos are formed when sunlight or moonlight is
  transmitted through ice crystals
• Halos indicate the presence of cirriform cloud
  types - refraction
• Sundogs are two spots refracted in the same plane
  as the observer is positioned refraction
• Ice crystals are parallel to earths surface
• Sun pillars are reflected vertical shafts of
  light - reflected

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Why does this often hold true?

• Rainbow in the morning, sailors take warning
  rainbow at night, a sailors delight?

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Rainbows

• Rainbows (animation)

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Corona Iridescence

• What are the primary differences between a corona
  and halo?
• How is refraction and diffraction related to
  these forms of optical weather phenomena?

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End Chapter 15

• What is the Fata Morgana?