1. Atmospheric Phenomena
Light, Color, and Observations

2. White and Colors Rods and cones in human eye
0.4 µm – 0.7 µm visible light
All wavelengths viewed at once = white
Specific wavelengths = color (ROYGBIV)

3. White Clouds and Scattered Light
Reflection and scattering (diffuse light)
Geometric scattering
White clouds scatter light
Black clouds have large cloud droplets which absorb light, rain likely

6. Blue Skies and Hazy Days
Selective scattering
Rayleigh scattering
Blue haze (terepenes)
Crepuscular rays

9. Red Suns and Blue Moons
A thick atmosphere selectively scatters all but red sunlight.
A low solar angle (sunrise or sunset) causes light to travel through a greater distance or thicker atmosphere.
Same process for a blue moon

11. Twinkling, Twilight, and the Green Flash
Transmission, refraction
Light that travels from a less dense to a more dense medium loses speed and bends toward the normal, while light that enters a less dense medium increases speed and bends away from the normal.
Apparent position, scintillation, twilight, green flash

14. The Mirage An object appears to be displaced from true position.
Inferior: down to ground
Superior: up into air
Observation: Fata Morgana
Fairly uniform surface is transformed into one of vertical walls and columns with spires
Usually in polar regions with warm air over a cold surface

17. Halos, Sundogs, and Sun Pillars
Halo and cirriform clouds : 22º and 46º, tangent arc
Dispersion
Sun dogs, parahelia
Sun pillars
Ice plates vs. ice columns

21. Rainbows
Face falling rain with sun at back, water drops disperse light
Primary vs. secondary
Observation: Rainbow, no rain?
Other substance besides rain can refract or disperse light (such as ice crystals) and form rainbow.

23. Coronas and Iridescence
Corona: bright ring of light created by diffraction
Iridescence: bright pastel colors of clouds created by diffraction
Observations: Gloried and Heiligenschein
Rings surrounding shadows