The data quality table summarizes the estimated amount of contamination (primarily bubbles) and data drop-outs in each section from every cruise for the OS38khz. For each cruise, the ship's speed (negative) was plotted versus measured velocities in the forward-ship direction. Significant bubble contamination shows up as a large difference between the ship velocity and the forward measured velocities. Each plot was visually inspected and an estimate of bubble contamination and the amount of available data for each section was produced. These estimates are summarized in the table below for the OS38 kHz ADCP. Slowly work is progressing on a similar table for the OS150Khz data.
In the table you will find five separate sections referred to, which represent each leg of the cruise from port to port. Since the ship travels repeated cruise tracks, this is a natural method of comparing sections from cruises over time. However, these sections will differ depending on whether they are an eastern Caribbean cruise track or a western Caribbean cruise track. In addition, some smaller subset of the cruise tracks may have been modified from the norm, particularly in the summer months, due to tropical cyclone events.
Below are two plotted examples of the method of identifying bubble contamination described above. (Thanks to Jules Hummon for this easy method).
| Example of a cruise with no bubble contamination | Example of a cruise with heavy bubble contamination in the last secion |
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