[JA]

If real, it's a shot well before sunrise, helped by the absence of cloud in picking up the full extent of the Rayleigh scattering and refraction of light as the sunlight light traces a much longer path through the atmosphere than during the day. There is also a phenomenon some refer to as green-flash that occurs briefly in the last moments of sunset or early moments of sunrise which might somehow factor in as a type of refraction.

Additionally the image may have had some amped-up in-camera or post-processing (increased saturation, contrast, sharpening etc..) as suggested by the white "ringing" edge on the silhouette of the horizon landscape.

Where did you see or source the image?

Best
JA