UH LADCP Documentation


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LADCP operator: Typical cast

The following is a typical cycle of tasks during a cast on a CLIVAR cruise. This is only “typical” (your details may vary).

Deployment and Recovery

Starting with the rosette being back on the deck, at the end of a cast, a typical cycle of tasks is:

  1. Hardware Recovery

    • Always make sure the power supply to the battery is OFF before unplugging any cable: be aware of what leads may have live power.

    • Clean the power/communication cable of the LADCP with freshwater and plug it into the cable that goes to the acquisition PC (located in the wet lab). See:

  2. Data Download

    • Download the data from the acquisition PC while the battery (the so-called Safe Orange Battery or SOB) is being charged. When the downloading is finished, run a quick test to make sure the data make sense. Finish filling in the acquisition log sheet and toggle off the charger when the SOB is charged. See:

  3. Processing, Plotting, Backups (See below). If there is any time available between the end of the download and the beginning of the next cast, that is when you can work on the data.

  4. Deployment: next cast

  5. Processing, Plotting, Backups (See below). While the CTD cast is underway, you can work on the data.

Processing, Plotting, Backups


The actual backup scheme here is specific to our goal of having a “processing” computer and a “logging” computer, and having each be able to step in as a direct replacement for the other. That makes the directory scheme and backup scheme a bit cumbersome.

During the time the rosette is underwater and is acquiring data or if there is time between casts, these are the tasks that need attention:

  1. backup/download data
  1. first check of data

    • run Python programs to plot timeseries of pressure, temperature, beam velocities etc, to verify that all beams are working and it is safe to use these LADCP transducers for the next cast.

  2. process data

  • all-python processing (shear method) is not fully functional yet, but should be good enough to get a decent profile if the scattering is good: advantage – no Matlab license required

  • process the data on the processing PC using the Lamont-Doherty Earth Observatory (LDEO) LADCP software with MATLAB.

  1. plot figures

    Plot vertical sections of U and V against time, latitude and/or longitude; top view of the horizontal velocity averaged over different depth ranges, etc, that can be viewable by the rest of the cruise members on the local website. See:

  2. download/backup other data

NOTE: One task needs to be done (more or less) every 4 or 5 casts, which is to check the build-up of the gas bubble in the SOB and to release some of it if necessary (see purging).

Important cautions and warnings

  • Never bend or twist connectors.

    • use a simple “pull” to unplug
    • use a simple “push” to plug
  • Never dry a plug with a paper towel.

    • use Kimwipes or other lint-free absorbent paper to blot the connector dry. It’s OK to dry the outside of the plug with a paper towel, but not the parts that mate.
  • In general, do not edit anything in home/currents/programs unless you find a bug and are confident of the solution.


If there is any problem or if you have any doubt, contact us: