Float 48 is now working very well. The recent calm weather has allowed the float ballast to tuned to better than 1g over all depths. The key has been to have the float settle to reference isopycnals at depths ranging from about 200m to about 15m. I have then adjusted to float's modeled equation of state, i.e. its volume as a function of pressure, to match this data. The main difficulty is the presence of an air-like component whose magnitude changes with time and has to be empirically determined.

The figure shows mapped float chlorophyll and density contours. The magenta lines show the float motion during Lagrangian drifts, the small dots show profile data.

Notice how during the last 5 days, the float rapidly oscillates in the vertical during the Lagrangian drifts. The float is being carried vertically by the turbulence in the mixed layer; its depth outlines the depth of mixing. A few days ago, the wind was weak and the mixing only extended to 10-20m. During the last day, the wind has been stronger and the mixed layer, and depth of float penetration, has reached 50m. Notice also how the chlorophyll has also been mixed during the recent storm.