Two images of the setting sun taken two minutes apart by Shaun Lowe (more of his images) of Nova Scotia, Canada.   Above centre on the left hand image a sunspot remains visible in spite of the atmospheric distortion. The sun is noticeably flattened and is crossed by steps and ripples. The steps show the presence of air layers at different temperatures. The ripples indicate waves in the layers. More severe temperature differences between layers produce sunset mirages and green flashes.