Metadata Report for BODC Series Reference Number 41109

• Metadata Summary

• Problem Reports

• Data Access Policy

• Narrative Documents

• Project Information

• Data Activity or Cruise Information

• Fixed Station Information

• BODC Quality Flags

• SeaDataNet Quality Flags

Metadata Summary

Problem Reports

No Problem Report Found in the Database

Data Access Policy

Open Data supplied by Natural Environment Research Council (NERC)

You must always use the following attribution statement to acknowledge the source of the information: "Contains data supplied by Natural Environment Research Council."

Narrative Documents

IOS Off-Shore Pressure Recorder Mark III

The main part of the capsule is a forged aluminium sphere of 0.66m internal diameter, which contains the data logging system, acoustic command and release units and all battery supplies. Each half of the sphere is bolted to a central equatorial ring, a seal being provided by O rings.

There are twelve outlets through this ring for Marsh Marine type electrical connectors. The sphere is housed in a free flooding tubular aluminium alloy frame. Also mounted on this frame are 2 pressure transducers, a sea temperature unit, 2 subsidary platinum resistance thermometers for measuring sea temperature and 2 wound nickel scrolls that act as acoustic pinger beacons. The frame and sphere, complete with attachments, have a positive buoyancy, and in order to anchor them, they are mounted on a steel tripod. The tripod is attached to the main frame by a central pyro-release unit.

The system incorporates a commercial data logger modified to operate in the deep sea capsule. The logger will accept input from a total of twelve separate sources or channels. The temperature and pressure sensors have variable frequency outputs. The frequencies are counted over a 890 second period and the total count for each channel is then recorded during a scan of all channels which lasts for 10 seconds. Thus the averaged integrated pressure and temperature values are logged every 15 minutes. Temperature is measured to correct for the temperature coefficient of the pressure transducers.

Data Processing Notes

Clock gained 5 seconds over 20 days 4 hours 59 minutes 55 seconds; the cycle interval and time values have been corrected.

Instrument Characteristics

Station D3

IOS Data Processing of Off-Shore Pressure Recorder Data

Data processing comprises 2 stages:-

1. Instrumental drift and depth are removed, thus the drift free series is produced with an artificial mean of zero.

2. Generally the pressure values have been obtained by integration and averaging over the sampling interval, followed by logging; hence the time value assigned to a data cycle has been chosen as the mid-point between the start and end time of each interval. Some pressure records have been sample rate reduced from the basic time step of the recorder to produce either hourly or 15 minute values, incorporating any timing corrections due to clock error.

Project Information

No Project Information held for the Series

Data Activity or Cruise Information

No Data Activity or Cruise Information held for the Series

Fixed Station Information

No Fixed Station Information held for the Series

BODC Quality Control Flags

The following single character qualifying flags may be associated with one or more individual parameters with a data cycle:

SeaDataNet Quality Control Flags

The following single character qualifying flags may be associated with one or more individual parameters with a data cycle: