Global Distribution of the Oceanic Bottom Mixed Layer Thickness

Abstract

Abstract The ocean bottom is the Earth's least explored region, and the bottom mixed layer (BML) is the pathway for communication between the ocean interior and the ocean floor. In this study, we used full‐depth conductivity‐temperature‐depth profiles archived by the World Ocean Circulation Experiment Program to obtain the first approximation of the global distribution of the oceanic BML thickness, H B M L , by applying an integrated method (Huang, Cen, et al., 2018, https://doi.orag/10.1175/jtech-d-18-0016.1 ). We found that the median H B M L values were 40, 42, and 64 m in the Atlantic, Indian, and Pacific Oceans, respectively, and 47 m globally. Statistically, the peak values for the median H B M L were around 20°N or 20°S, and it had weak dependence on the buoyancy frequency, where a thin H B M L corresponded to strong stratification. In addition, the median H B M L became thicker with the ocean depth ( D ), according to H B M L = 26.34 + 0.85 e ( D /1271.8) .