Oceanography

Factors Affecting Salinity

Factors that affect the salinity of the oceans can be broadly grouped into two categories, (a) factors that increase salinity and (b) factors that decrease salinity. The factors responsible for increase of salinity are : (i) evaporation (ii)Ice formation, (iii) advection of more saline water (iv) mixing with more saline deep water and (v) solution of salt deposits. The factors that are responsible decrease of salinity are: (i) Precipitation, (ii) melting of ice (iii) advection of less saline water, (iv) mixing with less saline deep water and (v) inflow of fresh water from land. Surface salinity changes are chiefly determined by three processes, namely, (a) decrease of salinity by precipitation, (b) increase of salinity by evaporation and (c) change of salinity by mixing processes. However, over large areas in the oceans, changes in surface salinity depend mainly upon changes in the difference between evaporation and precipitation.