This bow is the product of small droplets that probably did not even reach the ground as rain.

The split primary bow could be due to two sheets or layers of different size droplets each producing a bow of different size. As drop size decreases diffraction effects become increasingly significant. The rainbow broadens and shrinks.



Supernumeraries are also diffraction effects. They were first called ‘supernumeraries’ because, in ray optics, they were not supposed to exist. Their separation and width increases as droplets get smaller. Here the drops are evidently smaller towards the top of the picture.