Atmospheric
Optics
Four Bows
~ Between the well known primary and secondary bows, a third shoots up at a strange angle. A fourth is in the sea. Seen by Sarah Sayers at Killult Pier, Gortnhork, Donegal, Ireland.
The third bow is a 'reflection' rainbow. Sunlight is reflected upwards from calm water (or even flat and wet beach sand).
To a rainbow it looks as though a second sun is shining from beneath the water. the second sun forms a rainbow with its centre in the sky.
The bow below the horizon is a 'reflected' bow. Rays already refracted and reflected by raindrops reflect again from the calm water.
