Water mass
An oceanographic water mass is an identifiable body of water with a common formation history which has physical properties distinct from surrounding water. Properties include temperature, salinity, chemical - isotopic ratios, and other physical quantities.
Water masses are generally distinguished not only by their respective tracers but also by their location in the Worlds' oceans. Water masses are also distinguished by their vertical position, so that there are surface water masses, intermediate water masses and deep water masses.
Common water masses in the world ocean are: Antarctic Bottom Water, North Atlantic Deep Water, Circumpolar Deep Water, Antarctic Intermediate Water, Subantarctic Mode Water, Arctic Intermediate Water, North Pacific Intermediate Water, the central waters of various oceanic basins, and various ocean surface waters.
