The image above was reported and explained at The Guardian as a "superior mirage," defined as follows at Wikipedia:
"A superior mirage is one in which the mirage image appears to be located above the real object. A superior mirage occurs when the air below the line of sight is colder than the air above it. This unusual arrangement is called a temperature inversion, since warm air above cold air is the opposite of the normal temperature gradient of the atmosphere during the daytime. Passing through the temperature inversion, the light rays are bent down, and so the image appears above the true object, hence the name superior. "
A major tip of the blogging cap to reader Drabkikker, who points out in his comment that this is NOT an image of a superior mirage, but rather that of a false horizon. The distinction between the two is carefully and lucidly explained in this video:
Those who would like to explore the physics of optical illusions and meteorology might enjoy making use of the engine displayed in the video, which is at this link.