Oh, what a sight!
Marlin Bloethe caught this “omega sunset” on January 12, 2021 at Fishers Island, New York, looking westward over Long Island. She was right at the end of the Race Rd (before crossing the airstrip ) and Race Rock lighthouse is to the left of the “water tower island”.
Marlin shared this description of refraction from earthsky.org, the website that has added her amazing photo into their post of perfect examples of Omega! “This kind of mirage is called omega because of its resemblance to the Greek letter Ω and occurs due to a change in temperature, a temperature gradient, in the vertical direction above the horizon.” Jules Verne likened this appearance to an Etruscan vase.
Les Cowley at the website Atmospheric Optics explains omega sunsets this way, “The lower sun is not a reflection from the water. It is an ‘inferior mirage’, so named not from any poverty in appearance but because the miraged sun is below the ‘real’ one. The lower sun is an inverted image produced by refraction by a layer of warmer and less dense air close to the ocean surface. The discus shape is a combination of the upper limb of the erect sun and an inverted image of it beneath.”
Carl Sagan once said: “It does no harm to the romance of the sunset to know a little bit about it.”