From the photographer's webpage:

"Yes, this is a genuine picture of a real mirage. In Antarctica they happen quite often, each time there is absolutely no wind (well, okay, that's rare enough around windy DdU). The atmospheric turbulence needs to be really low, the air really pure (not a problem there) and dry. We saw dozens of them. The stripes in the foreground are alternating slabs of ice, snow-covered ice and sea water; the picture was taken in autumn at a time when only parts of the sea are frozen."

The original page is here: http://www.gdargaud.net/Antarctica/AntarSky.html

Careful, though! He gets his explainations on sound channels wrong...