Water Mass
D1. Physical and chemical oceanography and marine meteorologyDefinition
Body of water with distinctive temperature, salinity, and chemistry.
A water mass is a body of seawater with a distinctive and traceable combination of temperature, salinity, and other properties acquired at a common formation region, then conserved as it spreads along isopycnals. Oceanographers identify water masses on temperature-salinity diagrams, where each plots as a characteristic curve or point. Mixing between masses follows straight lines on a T-S plot, letting analysts decompose a profile into source fractions.