Atmospheric Optics Refraction Refraction Refraction In

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$Atmospheric Optics Refraction Refraction Refraction In$ Atmospheric Optics Refraction The amazing variety of optical phenomena observed in the atmosphere can be explained by four physical mechanisms. • Green Flash • Mirage • Scattering • Halo • Reflection • Tangent Arc • Refraction • Rainbow • Diffraction 1 2 Refraction Refraction in Air 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. Mirage 3 4 Refraction in Air Refraction in Air Mirage Green Flash 5 6 Refraction in Air Green Flash 7 8 Refraction in Air Refraction in Air Green Flash Green Flash 9 10 Refraction by Ice Crystals Refraction in Air Red Flash 22 1/2˚ Halo 11 12 Refraction by Ice Crystals Refraction by Ice Crystals Sun Dogs Sun Dog 13 14 Refraction by Ice Crystals Refraction by Ice Crystals 22 1/2˚ Halo 22 1/2˚ Halo and Upper Tangent Arc 15 16 Refraction by Ice Crystals Refraction by Ice Crystals 22 1/2˚ Halo Halo Complex 17 18 Refraction by Ice Crystals Refraction by Ice Crystals 46˚ Halo? Halo Complex 19 20 Refraction by Ice Crystals Refraction by Ice Crystals Lower Tangent Arc Lower Tangent Arc 21 22 Refraction and Scattering Refraction by Water Drops Sun Pillar and Sun Dog? 23 24 Refraction by Water Drops Refraction by Rain 25 26 Refraction by Water Drops Refraction by Rain Violet Red Primary Rainbow Double Rainbow 27 28 Refraction by Rain Refraction by Rain Double Rainbow Partial Rainbow 29 30 Refraction by Rain Refraction by Rain Double Rainbow High Sun: Low Rainbow 31 32 Refraction by Rain Refraction by Rain ! Rainbow seen from Airplane Low Sun: High Rainbow 33 34 Diffraction Diffraction causes Interference 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. Diffraction is the tendency of light waves to bend as they pass the edges of objects. 35 36 Diffraction by Soap Film Diffraction by Cloud Drops Examples include: • Iridescence • Corona • Glory • Supernumerary bows Iridescence 37 38 Diffraction by Airplane Window Diffraction by Cloud Droplets Artificial Iridescence Corona 39 40 Diffraction by Pollen Diffraction and Reflection Corona Glory 41 42 Diffraction and Reflection Diffraction and Reflection Glory Glory 43 44 Diffraction and Reflection Diffraction and Reflection Supernumerary Rays ! Fog Bow: larger drops do not allow dispersion of colors. 45 46 Diffraction and Reflection ! Fog Bow: larger drops do not allow dispersion of colors. 47.

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