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Geosciences LibreTexts

7.8: "Cline Curves" and Mixing (Surface) Zone

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    10257
    • Contributed by Miracosta Oceanography 101
    • Sourced from Miracosta)

    The "Cline Curves" - changes in temperature, salinity, and density with depth

    • Thermocline - a steep temperature gradient in a body of water marked by a layer above and below which the water is at different temperatures.
    • Halocline - a vertical zone in the oceanic water column in which salinity changes rapidly with depth.
    • Pycnocline - a layer in an ocean or other body of water in which water density increases rapidly with depth.

    Clne curves
    Figure 7.26. The "cline curves"

    NOAA Animation: Annual changes of pychnocline depth

    Mixing (Surface) Zone

    Uppermost water where mixing from currents make temperature, salinity, and density mostly constant.

    Vertical changes in temperature with latitude:
    Polar regions have almost no thermocline.
    Temperate regions have weak thermoclines (moderate in summer, less in winter).
    Tropical regions have a strong thermocline.

    Mixed Layer above the thermoline and deep water.
    Figure 7.27. Mixing Zone