Measuring Turbulence Mixing in Indonesian Seas using Microstructure EM-APEX Floats

PROJECT SUMMARY We propose an observational program to study turbulence mixing in Indonesian waters using two microstructure EM-APEX floats. Previous studies have suggested strong tidal and inertial wave mixing in the Banda Sea and Makassar Strait. Unfortunately, observations are very limited due to the lack of ship time opportunity in the area. We are invited by Indonesian oceanographers Dr. Indra Jaya and Dr. Agus Atmadipoera at Bogor Agricultural University, Indonesia to join oceanographic cruises on Indonesian ships in summer-fall 2015 to conduct turbulence measurements using EM-APEX floats in Indonesian waters (see the attached invitation letter). The experiment sites will include the Banda Sea, Flores Sea, and south of Makassar Strait. We are proposing an innovative method to measure turbulence mixing in these regions, where we expect vigorous diapycnal mixing activity, using the autonomous microstructure EM-APEX floats, in collaboration with Indonesian colleagues. Microstructure EM-APEX floats measure turbulent thermal diffusion rate, horizontal velocity, temperature and salinity, vertical shear, stratification, and thereby the Richardson number. Estimates of turbulent kinetic energy dissipation rates and eddy diffusivity can be inferred. Combining with direct measurements of small-scale shear, stratification, and Richardson number, we can investigate the turbulence parameterization in the energetic Indonesian waters. Microstructure EM-APEX floats have been used in previous ONR LatMix experiments and successfully obtained quality microstructure and small-scale measurements.