Any piece, body, or area of ice that is in the process of melting or disintegrating. It is characterized by honeycomb structure, weak bonding between crystals, or the presence of meltwater or seawater
between grains. Rotten ice may appear transparent (and thus dark) when saturated with seawater and so may be easily confused with newly forming black ice.
First-year ice subjected to fracturing and hummocking at the stage of young ice, that has formed as a result of the freezing together of pancake ice or of fragments of fresh ridges that have collapsed
into fractures after the end of compaction and the onset of ice divergance. The irregularities cover significant areas where snow accumulation increases and the heat conductivity and the tangential stress coefficient significantly change. During a radar sounding, segments of rough ice are depicted by increased brightness with ice ridges being indiscernible. As a result of further growth, the irregularities at the bottom surface of rough ice are usually completely smoothed by the end of winter and the ice thickness becomes approximately equal to that of ice of the same age of quiet growth. During the period of summer melting, all small irregularities at the surface of ice fields are smoothed; hence this type of relief is typical only of first-year ice.
Same as transition layer. The lowest atmospheric layer immediately adjacent to a surface covered with relatively large roughness elements such as stones, vegetation, trees, or buildings.