Distribution and formation of halocline in the world ocean

Distribution and formation of halocline in the world ocean was investigated through analysis of climatological hydrographic data. A simple definition was used for halocline, i.e. halocline was defined as the layer with the strongest vertical salinity gradient in the vertical direction. Strong halocline was observed in the tropics, equatorward subtropical regions and subpolar regions, and absent in the central subtropical regions. While halocline was mainly formed by surplus precipitation and Ekman-upwelling in the tropics and subpolar regions, it was formed by saline water subduction in the equatorward subtropical regions. While distribution of halocline was almost the same throughout the year, significant seasonal variation was observed in the halocline strength.