An untethered free-fall vertical profiler for deep ocean mixing measurements

The research on the process of deep-ocean turbulent mixing has become one of the frontier technologies in the field of scientific research. Currently, the most commonly used profiler is the tethered vertical profiler, however its measuring depth is limited by the length of the rope. An untethered free-fall vertical profiler which can profile down to a depth of 4000m is developed by Institute of Deep-sea Science and Engineering, Chinese Academy of Science. The profiler equipped with microstructure sensors (two orthogonal shear probes and one fast response thermistor) is used to measure the ocean turbulent mixing and estimate the rate of dissipation of turbulent kinetic energy (TKE) and temperature gradient. The sea trail of profiler was conducted in the South China Sea and the shear spectra from 920 to 1020m agree with the Nasmyth spectrum.