“Normal” atmospheric refraction increasingly flattens the sun as it approaches the horizon.    The refraction raises the apparent sun above the true one.   The effect strengthens closer to the horizon so the lower part of the disk is raised most, resulting in an oval shape - from space this is extreme.

Then the sun’s light starts to pass through an inversion layer, abnormally warmer air above cooler.   Sunlight is refracted by the density gradients to give a ‘mock-mirage’.      With a single inversion layer there are three images, an upper erect one, a lower ascending inverted image and a lower descending erect one.    Here the inversion layer is more complex giving more sun slices.

Mock-mirages often give green or ble flashes on the top of the sun. The classical inferior mirage produces a longer and more intense flash close to the horizon.