Oceanic Mixed Layer Depth Climatology

An oceanic mixed-layer-depth climatology is a gridded reference dataset of the seasonally varying depth of the surface layer that is near-uniform in temperature and density from wind and convective mixing. The widely used de Boyer Montegut compilation defines the depth from individual Argo and ship profiles using a density threshold near 0.03 kg per cubic meter (or a 0.2 degree Celsius temperature criterion) from a 10-meter reference, then averages by month. Mixed-layer depth ranges from under 20 meters in summer to over 500 meters in winter convective regions, and it sets air-sea heat capacity, light exposure for phytoplankton, and water-mass subduction.