The displacement relative to isotherms can be found from the temperature record. The rate of change of this is the cross-isotherm velocity w. The temperature will change only when the instrument crosses isopycnals. Temperature is measured hourly, as are pressure and revolution. This velocity is not fully resolved since N is about 1 cph.

The displacement relative to an isotherm is given by delta-Z = delta-T / (dT/dz). dt/dz is about 1.1 millidegree C per meter near the float. Since the instrument sank about 30 meters in the 100 day mission the fluctuation delta-T is computed relative to a polynomial fit to the 100-day T record.

Cross-isopycnal (cross-isotherm) velocities can possibly cause the shearmeter to rotate, giving noise to the shear measurement. This type of mechanical response is undesirable. The w record is not obviously correlated with the rotation record.