volume_fraction_of_ridged_ice_in_sea_ice 1 [UUUU] "Volume fraction" is used in the construction "volume_fraction_of_X_in_Y", where X is a material constituent of Y. It is evaluated as the volume of X divided by the volume of Y (including X). It may be expressed as a fraction, a percentage, or any other dimensionless representation of a fraction. Sea ice "ridging" occurs in rough sea conditions. The motion of the sea surface can cause areas of sea ice to deform and fold resulting in ridged upper and lower surfaces. The ridges can be as much as twenty metres thick if thick ice is deformed. "Sea ice" means all ice floating in the sea which has formed from freezing sea water, rather than by other processes such as calving of land ice to form icebergs. This quantity specifically refers to the volume of ice that is ridged or dynamically deformed, divided by the total volume of sea ice that yields the fraction.