Some sunsets exhibit a phenomenon called "green flash," where there is a quick flash of green light right as the sun is setting. I have seen this myself several times, and sort of understand it. I am a bit frustrated at my inability to explain it better to my family.
I understand how Rayleigh scattering would make the dominant color shift towards the blue just after the sun passes below the horizon. How does mirage cause the green light to refract more than the blue? Is there an easy way to use the two effects to estimate the wavelength of the flash?