Metadata Report for BODC Series Reference Number 36906

Metadata Summary

Data Description
Data Category Offshore sea floor pressure series
Instrument Type
NameCategories
Institute of Oceanographic Sciences MkIV bottom pressure recorder  sea level recorders
Instrument Mounting fixed benthic node
Originating Country United Kingdom
Originator -
Originating Organization Institute of Oceanographic Sciences Bidston Laboratory (now National Oceanography Centre, Liverpool)
Processing Status banked
Project(s) -
 

Data Identifiers

Originator's Identifier G3DP6/SMDFH0
BODC Series Reference 36906
 

Time Co-ordinates(UT)
Start Time (yyyy-mm-dd hh:mm) 1981-12-14 08:00
End Time (yyyy-mm-dd hh:mm) 1982-03-11 06:00
Nominal Cycle Interval 3600.0 seconds
 

Spatial Co-ordinates

Latitude 14.70590 N ( 14° 42.4' N )
Longitude 48.84040 W ( 48° 50.4' W )
Positional Uncertainty 0.1 to 0.5 n.miles
Minimum Sensor Depth 3527.0 m
Maximum Sensor Depth 3527.0 m
Minimum Sensor Height 0.0 m
Maximum Sensor Height 0.0 m
Sea Floor Depth 3527.0 m
Sensor Distribution Fixed common depth - All sensors are grouped effectively at the same depth which is effectively fixed for the duration of the series
Sensor Depth Datum Instantaneous - Depth measured below water line or instantaneous water body surface
Sea Floor Depth Datum Instantaneous - Depth measured below water line or instantaneous water body surface
 

Parameters
BODC CODE Rank Units Title
AADYAA01 1 Days Date (time from 00:00 01/01/1760 to 00:00 UT on day)
AAFDZZ01 1 Days Time (time between 00:00 UT and timestamp)
PPSSRL01 1 Decibars Pressure (measured variable) exerted by the water body by fixed in-situ pressure sensor and corrected using co-located air pressure data expressed to unspecified datum by subtraction of a constant
 

Definition of Rank
  • Rank 1 is a one-dimensional parameter
  • Rank 2 is a two-dimensional parameter
  • Rank 0 is a one-dimensional parameter describing the second dimension of a two-dimensional parameter (e.g. bin depths for moored ADCP data)

Problem Reports

No Problem Report Found in the Database

Data Access Policy

Public domain data

These data have no specific confidentiality restrictions for users. However, users must acknowledge data sources as it is not ethical to publish data without proper attribution. Any publication or other output resulting from usage of the data should include an acknowledgment.

The recommended acknowledgment is

"This study uses data from the data source/organisation/programme, provided by the British Oceanographic Data Centre and funded by the funding body."

Narrative Documents

IOS Mk IV Pressure Recorder

This instrument was developed at I.O.S. Bidston and is a deep water pressure recorder (i.e. used at depths between 300m and 5000m). Each recorder consists of one or two Bell and Howell strain gauges and/or a Digiquartz pressure sensor and a temperature sensor.

The sensors are interfaced into a Seadata cassette recording system. Sampling is usually every 3.75 minutes with the integration period equal to the sampling interval, but may be set to other sampling intervals. For example with a 3 second sampling interval and integration period the instrument may be used as a wave recorder.

The recorder is housed in a tubular aluminium frame 1.3m in diameter by 1.4m in height attached to a disposable steel ballast weight. The data logger together with the associated battery supply is lowered into a central 15cm (internal diameter) aluminium tube. Sensors are mounted externally with Marsh Marine connectors. The assembly free falls to the sea floor. An acoustic release system is used to separate the ballast weight and buoyancy is provided by Corning glass spheres attached to the aluminium frame.

Data Processing Notes

Clock lost 1 minute 3 seconds over 89 days 20 hours 19 minutes 3 seconds; the original cycle interval and time values have been corrected.

Instrument Characteristics

Station G3
OSTG Mark IV No. 5
Sensors B+H4 (BODC Series Ref. 36899)
DQ2291(BODC Series Ref. 36906)
Nominal sampling interval 225secs
Integration period 225secs
Actual sampling interval 225.001826secs

IOS Data Processing of Off-Shore Pressure Recorder Data

Data processing consists of two stages:-

  1. Pressures have been sample rate reduced from the basic time step of the recorder to produce the hourly values and have been interpolated by a cubic spline to generate the value on cardinal hours.

  2. Instrumental drift has been removed and the drift free series is produced with an artificial mean value, usually of 100mbar.

BODC Quality Control Flags

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

Flag Description
Blank Unqualified
< Below detection limit
> In excess of quoted value
A Taxonomic flag for affinis (aff.)
B Beginning of CTD Down/Up Cast
C Taxonomic flag for confer (cf.)
D Thermometric depth
E End of CTD Down/Up Cast
G Non-taxonomic biological characteristic uncertainty
H Extrapolated value
I Taxonomic flag for single species (sp.)
K Improbable value - unknown quality control source
L Improbable value - originator's quality control
M Improbable value - BODC quality control
N Null value
O Improbable value - user quality control
P Trace/calm
Q Indeterminate
R Replacement value
S Estimated value
T Interpolated value
U Uncalibrated
W Control value
X Excessive difference