refraction refraction in air · 2005-10-21 · atmospheric optics ¥ scattering ¥ reßection ¥...

$: Refraction Refraction in Air · 2005-10-21 · Atmospheric Optics ¥ Scattering ¥ Reßection ¥ Refraction ¥ Diffraction The amazing variety of optical phenomena observed in the$
Atmospheric Optics

• Scattering

• Reflection

• Refraction

• Diffraction

The amazing variety of optical phenomena observed in the atmosphere can be explained by four physical mechanisms.

1

Refraction

• Green Flash

• Mirage

• Halo

• Tangent Arc

• Rainbow

2

Refraction

Light slows down as it passes from a less dense to a more

dense medium.

As light slows it bends toward the

denser medium. Similar to waves approaching a beach.

The amount of bending depends on the wavelength (color) of the

light, leading to dispersion or separation of colors.

3

Refraction in Air

Mirage

4

Refraction in Air

Mirage

5

Refraction in Air

Green Flash

6

7

Refraction in Air

Green Flash

8

Refraction in Air

Green Flash

9

Refraction in Air

Green Flash

10

Refraction in Air

Red Flash

11

Refraction by Ice Crystals

22 1/2˚ Halo

12


Sun Dogs

13


Sun Dog

14


22 1/2˚ Halo

15


22 1/2˚ Halo and Upper Tangent Arc

16


22 1/2˚ Halo

17


Halo Complex

18


Halo Complex

19


46˚ Halo?

20


Lower Tangent Arc

21


Lower Tangent Arc

22

Refraction and Scattering

Sun Pillar and Sun Dog?

23

Refraction by Water Drops

24


25

Refraction by Rain

26


Primary Rainbow

Violet

Red

27

Refraction by Rain

Double Rainbow

28

Refraction by Rain

Double Rainbow

29

Refraction by Rain

Partial Rainbow

30

Refraction by Rain

Double Rainbow

31

Refraction by Rain

High Sun: Low Rainbow

32

Refraction by Rain

Low Sun: High Rainbow

33

Refraction by Rain

! Rainbow seen from Airplane

34

Diffraction

Constructive interference of light waves can produce

color separation.

The physical mechanism in

this case is called diffraction.

Produces colors on soap

films, oil slicks, and music CDs.

35

Diffraction causes Interference

Diffraction is the tendency of light waves to bend as they pass the edges of objects.

36

Diffraction by Soap Film

Examples include:

• Iridescence

• Corona

• Glory

• Supernumerary bows

37

Diffraction by Cloud Drops

Iridescence

38

Diffraction by Airplane Window

Artificial Iridescence

39

Diffraction by Cloud Droplets

Corona

40

Diffraction by Pollen

Corona

41

Diffraction and Reflection

Glory

42


Glory

43


Glory

44


Supernumerary Rays

45


! Fog Bow: larger drops do not allow dispersion of colors.

46


! Fog Bow: larger drops do not allow dispersion of colors.

47

refraction refraction in air · 2005-10-21 · atmospheric optics ¥ scattering ¥ reßection ¥...

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