Surf Colours ~ Images by Jim Grant in California. A spray haze of colour surrounds the surfers. Iridescence and diffraction?  Or 'wavebows' and refraction?  Scroll down.
 All images ©Jim Grant, shown with permission
The colours are those of a 'rainbow' but one created not by raindrops but by small spherical drops of seawater created by the surf. In the foreground the drops might actually be rolling on the sea surface.

Refraction therefore?   Not entirely, when drops are small diffraction effects become noticeable in that the colours become less saturated and the bow also starts to widen.

Bows created by seawater have a slightly smaller radius than those from the purer water of raindrops. Sea water has a greater refractive index.

The difference is not noticeable unless a sea bow and rainbow are seen together.

This classic image was taken by J Dijkema while at sea in the Pacific. The lower (smaller) bow is from nearby sea spray. The upper (larger) bow is from rain.

Image ©Dijkema/Konnen shown with permission.
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