[Q] Rainbow shape from air/ ground

[paigetheoracle]

Why does a rainbow appear as an arch at ground level but a ring from the air?:eek:

[Jay-qu]

Because it is always a ring, you just cant see the whole arch from the ground :eek:

[Karnuvap]

Some people have reported that standing on a ridge overlooking a valley where it is raining they have seen a rain-circle. It is to do with the geometry of the sun and the observer (you).

 

In similar situations I have been in a plane and seen the shadow of the plane on some clouds below but the shadow is encircled by a bright ring of light. This is called a "Glory" and again it is to do with the symmetry of the sun being directly behind you and the sun's rays reflecting off ice crystals in the cloud this time.

 

Hope this helps.

 

The Vap.

[Turtle]

the spectral-colors atmosphereic circle from the air is not a "rainbow"; it is a "glory". rainbows both refract & reflect light into colors, glories only refract the light. there are colored circles seeable from the ground too, but these are called "halos". :shrug:

 

main page: >> Atmospheric Optics

 

page on glories: >>Coloured arcs not rainbows

Rainbows are formed by refraction and reflection of sunlight by raindrops. When sunlight passes through ice crystals, halos form and they are mostly coloured . Small cloud or fog droplets diffract light to form ringed glories, coronae and the jumbled colours of iridescent clouds.