Distribution and Seasonal Variation of Halocline in the World Ocean

The distribution and seasonal variation in the halocline in the world ocean were investigated using a simple halocline definition. The halocline was observed in the tropics, equatorward subtropical regions, and subpolar regions, but it was absent in the central subtropical regions. A strong halocline tended to occur in the area where sea surface salinity (SSS) was low. The seasonal variation in halocline strength was also correlated with variation in SSS. The correlation coefficient was mostly negative; the halocline was strong when the SSS was low. However, in the Gulf of Alaska in the northeastern North Pacific, the correlation coefficient was positive. There, the halocline was strong when the SSS was high probably due to entrainment effect.