Atmospheric
Optics
Netherlands Spring Sunset
Montage by Michiel de Boer. A warm wind blows over the cold North Sea. Cold air layers beneath warmer, the stuff of strong refraction and mirages. First the disk distorts and flattens. Turbulence between the layers ripples its lower limb. The sun flattens more against the inversion layer. Then the mirage, a mock-mirage, starts. A pie shape serrated by wind turbines as a second sun appears within the inversion.
All images ©Michiel de Boer, shown with permission.
The '3-sun mock-mirage'
The mirage forms during temperature inversions – unusually cooler air beneath warmer. Almost horizontal setting sun rays refract at the temperature/density gradients. They curve to appear to come from new directions.
The first sun, above the inversion layer, slides downwards. The layer appears to obscure the sun's lower edge giving the appearance of a sunset at a false horizon. This image seems to be the ‘real’ one but the second and third suns are no less real.
The second sun is wholly within the layer. We see just a slice. It is inverted. It rises as sunset progresses.
The third image , also within the layer, is upright and sinks.
