Supralateral arc

(Section 3.2.3.1.9)

This is a rainbow-coloured large arc that forms only when the light source is below 32° elevation. It appears as a fragment of a large circle and always above the elevation of the parhelic circle. The supralateral arc may be mistaken for the 46° halo, but can be distinguished from it by the brighter and more coloured appearance of the supralateral arc. In contrast to the large 46° halo, the shape of the supralateral arc varies with the elevation of the light source. The apex of the arc is near, or touches the circumzenithal arc. The supralateral arc is easily confused with the 46° halo. See Table 22 for differentiation characteristics.