CODAS+UHDAS Documentation

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On a per-cruise basis:

Recording

It’s probably easiest to have the data always end up in the same directories and choose a new cruise name to use. Then after the cruise you can stop logging and use a file browser to move the data to a different directory.

So, choose a new cruise name. Something simple and descriptive like TN165 or KM0404 for the whole cruise.

ADCP Setup TWO THINGS TO DO

  1. choose the text file to use
  2. Set time between Ensembles: change the gui “Ensemble Time” so it is consistent with your instrument’s frequency. This is done to maximize the number of pings that go in the water. The RDI default settings are conservative (i.e. they are designed so you won’t have ruined data; but you do have fewer pings per average)

NOTE:

“Ensemble Time” here refers specisically to the bottom of the “ADCP Setup” Tab, and it refers to the “seconds between ensemble” (where an ensemble is usually just one watertrack ping, or might be a pair of pings: one bottomtrack ping and one watertrack ping). This setting DOES NOT have anything to do with the averaging of the data later.

Three likely scenarios

BOTTOM TRACK ON

(TEMPORARILY probably)

If the cruise is going to be over shallow water (under 500m) for over 6 hours, transiting over a shelf for instance, it is a good idea to put it in bottom track mode. This helps with calibration of the data during processing and is a good sanity-check for the instrument, but it wastes too many pings if you’re in open water. You need to lengthen the “Ensemble Time” to account for the fact that there are 2 pings per ensemble – a bottom track ping and then a water track ping.

UPPER 500m

higher precision mode

If the cruise is in the open ocean and the science party is biologists or people interested in upper-ocean processes, use broadband pings with 8-meter resolution to get better vertical resolution and higher precision at the expense of depth penetration.

DEEP OCEAN, DEEPEST PROFILES

lower precision mode

If the cruise is in the open ocean and the scientists on board are interested in currents as deep as possible, use narrowband pings with 16-meter bins. Deepest profiles might be to 800m, but with lower vertical resolution.

scenario “Ensemble Time”
BOTTOM TRACK 3
UPPER 500m OCEAN 2
DEEPEST PROFILES 2

double these durations for 38KHz

NOTE:

It is important to remember to change the “Ensemble Time” to match the ping pattern. The computer actually tells the instrument when to ping; the ADCP doesn’t figure that out for itself. If it’s too small, you may have interference. If it’s too large, you waste the opportunity to ping.