Chapter 15: Light, color and atmospheric optics White and colors White and colors White clouds and scattered light White clouds and scattered light Blue skies and hazy days Blue skies and hazy days Red suns and blue moons Red suns and blue moons Twinkling, twilight, and the green flash Twinkling, twilight, and the green flash The mirage: seeing is not believing The mirage: seeing is not believing Halos, sundogs, and sun pillars Halos, sundogs, and sun pillars Rainbows Rainbows Coronas and cloud iridescence Coronas and cloud iridescence

White and colors

review of fate of visible light passing through the atmosphere review of fate of visible light passing through the atmosphere review of relationship between wavelength and colors review of relationship between wavelength and colors

White clouds and scattered light

reflection reflection scattering scattering Thunderstorms appear dark because the clouds (cumulonimbus) are about 10 km deep, scattering most of the light. Thunderstorms appear dark because the clouds (cumulonimbus) are about 10 km deep, scattering most of the light.

Blue skies and hazy days

selective scattering selective scattering effect of scattering particle size effect of scattering particle size crepuscular rays crepuscular rays

Red suns and blue moons

path length of sunlight passing through the atmosphere path length of sunlight passing through the atmosphere atmospheric particle effects atmospheric particle effects The “definition” of a blue moon as two full moons in a single calendar month has nothing to do with atmospheric optics. The “definition” of a blue moon as two full moons in a single calendar month has nothing to do with atmospheric optics.

The mirage: seeing is not believing

inferior mirage inferior mirage superior mirage superior mirage Mirages are very common and may be seen frequently if you look for them. Mirages are very common and may be seen frequently if you look for them.

Inferior mirage warm surface, decreasing temperatures aloft warm surface, decreasing temperatures aloft The proper conditions for an inferior mirage are commonly found over a hot road surface during summer, or over an unfrozen lake on a very cold day. The proper conditions for an inferior mirage are commonly found over a hot road surface during summer, or over an unfrozen lake on a very cold day.

Superior mirage cold surface, warmer temperature aloft cold surface, warmer temperature aloft The proper conditions for a superior mirage are commonly found over water and over snow-covered surfaces. The proper conditions for a superior mirage are commonly found over water and over snow-covered surfaces.

Fata morgana complex vertical temperature profile complex vertical temperature profile According to legend, King Arthur’s half-sister, Fata Morgana in Italian, was a fairy enchantress trained by Merlin the Magician. She lived in a crystal palace beneath the water and could build fantastic castles from thin air. According to legend, King Arthur’s half-sister, Fata Morgana in Italian, was a fairy enchantress trained by Merlin the Magician. She lived in a crystal palace beneath the water and could build fantastic castles from thin air.

Halos, sundogs, and sun pillars

Halos ice crystals ice crystals dispersion dispersion Halo-producing ice crystals are commonly found in cirrostratus clouds Halo-producing ice crystals are commonly found in cirrostratus clouds

Sundogs hexagonal ice crystals hexagonal ice crystals horizontal orientation horizontal orientation Sundogs are commonly seen when cirrostratus clouds are in the sky. Sundogs are commonly seen when cirrostratus clouds are in the sky.

Sun pillars reflection phenomenon reflection phenomenon Sun pillars can be seen shortly after sunrise or shortly before sunset on very cold days. Sun pillars can be seen shortly after sunrise or shortly before sunset on very cold days.

Rainbows

Rainbows water droplet phenomenon water droplet phenomenon reflection and dispersion reflection and dispersion necessary conditions for a rainbow necessary conditions for a rainbow the primary rainbow the primary rainbow

The secondary rainbow two internal reflections two internal reflections A tertiary rainbow also exists, but it is too faint to be seen with the human eye. A tertiary rainbow also exists, but it is too faint to be seen with the human eye.

Coronas and cloud iridescence

diffraction diffraction

The corona necessary conditions necessary conditions

Cloud iridescence another water droplet diffraction phenomenon another water droplet diffraction phenomenon

The Glory necessary conditions for viewing necessary conditions for viewing It is very common to see a glory from the window of an airplane. Make sure you are sitting on the side opposite the sun. It is very common to see a glory from the window of an airplane. Make sure you are sitting on the side opposite the sun.