Direction of the vertical velocity

A data file may start before an instrument is even in the water. Vertical profilers are often held near the surface before they are released. During such a time, the vertical velocity may fluctuate significantly around a mean of zero, but the data cannot be used for dissipation rate estimation. A data file may also contain many profiles that are interrupted by useless data, such as the retrieval of a tethered profiler back to the surface. The direction of profiling can be used to eliminate such segments.