Definition of pycnocline in US English:



  • A layer in an ocean or other body of water in which water density increases rapidly with depth.

    • ‘Saline and warm Mediterranean water flowing through the Bosporus Strait maintains a permanent pycnocline.’
    • ‘The polar regions are the only places where deep waters are ever exposed to the atmosphere because the pycnocline is not always present.’
    • ‘Specifically, more oceanographic research in Hudson Bay, particularly documenting pycnocline development, is needed.’
    • ‘Deployments of the HRS and measurements of microscale turbulence were made simultaneously in the mixed surface layer, the pycnocline, and the DCM.’
    • ‘Bezys and Risk suggested that the black shales and mudstone facies were the results of a stratified water column with a pycnocline.’


1950s: from Greek puknos ‘thick’ + cline.