Fine example of a bright Parry arc nesting inside the upper tangent arc. Parry arcs appear when the longest axes of the ice columns are oriented horizontally. They were named after their discoverer, Admiral Parry, who spotted one during his search for the northwest passage. Parry arcs may also have an opposite orientation (concave instead of suncave), as can be seen in the next image.
[Photo by Amy Turner - image found at www.crh.noaa.gov]