Mixed Layer
D1. Physical and chemical oceanography and marine meteorologyDefinition
Near-surface layer of nearly uniform temperature and salinity due to turbulent mixing.
The surface mixed layer is the near-surface band of nearly uniform temperature, salinity, and density kept homogeneous by wind stirring, wave breaking, Langmuir circulation, and convective cooling. It is the ocean’s contact zone with the atmosphere, setting sea surface temperature, gas exchange, and the light and nutrients available to phytoplankton. Its depth swings from a few meters in summer to hundreds of meters in winter deep-convection regions.