What is Salinity?
Salinity in the ocean is defined as the grams of salt per 1000 grams of water, wherein one gram of salt per 1000 grams of water is defined as one practical salinity unit or one PSU. Observations of salinity are needed to calculate estimates of oceanic transports of freshwater and other properties on basin to global scales. Salinity also provides a good pointer to changes in the water cycle as it indicates the change in freshwater due to the difference between precipitation and evaporation. Along with temperature, it is a major factor in contributing to changes in density of seawater and therefore ocean circulation.