I am very new to the world of mirages and would like some information as to the type of mirage in this picture which I took this morning. It is the cargo ship African Kalmia which passed my location at about 10am (UK time) this morning. I also have some great video of it moving along above the sea but I can't upload the file here. I have taken a picture of a superior mirage from the same location which I uploaded to this site last month, it was of another cargo ship with an inverted image on top. In that picture there was a clear heat haze line but today there wasn't any visible heat haze so I'm somewhat confused.
All mirages work on the same principle as fiber optics: a negative gradient of refraction index will create a region of small grazing angles with almost total reflection which confines light rays into the refraction index region with larger index.