Metadata Report for BODC Series Reference Number 34174

Metadata Summary

Data Description

Data Category Offshore sea floor pressure series
Instrument Type Tide gauge (unspecified)
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) IOS North Sea Experiment 1981

Data Identifiers

Originator's Identifier 814/981/126
BODC Series Reference 34174

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 1981-05-06 06:22
End Time (yyyy-mm-dd hh:mm) 1981-06-16 14:22
Nominal Cycle Interval 900.0 seconds

Spatial Co-ordinates

Latitude 53.23990 N ( 53° 14.4' N )
Longitude 2.09990 E ( 2° 6.0' E )
Positional Uncertainty 0.1 to 0.5 n.miles
Minimum Sensor Depth 35.0 m
Maximum Sensor Depth 35.0 m
Minimum Sensor Height 0.0 m
Maximum Sensor Height 0.0 m
Sea Floor Depth 35.0 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


BODC CODE Rank Units Short Title Title
AADYAA01 1 Days Date(Loch_Day) Date (time from 00:00 01/01/1760 to 00:00 UT on day)
AAFDZZ01 1 Days Time(Day_Fract) Time (time between 00:00 UT and timestamp)
PRSTPS01 1 Decibars TotPressSeaFL Pressure (measured variable) exerted by the water body plus atmosphere by fixed in-situ pressure sensor

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

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

Aanderaa Current Meter/Pressure Recorder

The instrument comprises a bottom mounted rig which utilises a Digiquartz sensor and an Aanderaa current meter (with the adaption of a small vane replacing the normal vane) both interfaced into a modified Aanderaa current meter logger. Current meter speed and absolute pressure count are integrated over a pre-selected period (usually 10 or 15 minutes) and sampled by the logger at the same pre-selected time interval, together with spot readings of vane direction, temperature, elapsed time and rig orientation. The pressure sensor consists of a convoluted bellows linked to a 40kHz quartz crystal resonator coupled by piezoelectric action to an electronic resonator. A quartz crystal clock is used for controlling the sampling interval.

The data are recorded on magnetic tape as 10 bit binary words in serial form with the frequency count from the pressure sensor stored as most and last significant counts. The pressure sensor pack, containing the Digiquartz type 2-300a quartz crystal pressure transducer but no temperature transducer, is mounted approximately 1m above the rig base, with the current meter 0.7m above the base. The rig is 1.5m in height and the base is formed by a tripod with legs of length approximately 0.7m. The current meter/pressure recorder is usually deployed using a U-shaped mooring (i.e. buoy or pellet float to wire rope to tide gauge to ground line to anchor to wire rope to buoy), but W-shaped moorings are used in conjunction with either current meters or thermistor chains. A W-shaped mooring comprises pellet float to pellet line to sub-surface buoy to current meter or thermistor line to anchor weight to ground line to tide gauge to ground line to anchor weight to wire rope to surface buoy.

IOS Calibration and Data Processing of Off-Shore Tide Gauge Data

Calibration of pressure/frequency sensors and thermistors are carried out using the facilities and staff at I.O.S. Bidston with the exception of pre 1975 pressure/frequency sensors, which were calibrated in the pressure chamber at I.O.S. Wormley.

The data are copied from the logger magnetic tape to 9 track magnetic tape and disk. The data are either listed or plotted as an initial check. A program is then used to check the data from the temperature sensor channels, calculate and plot the temperature values and store them (if temperature sensor channels are available).

A second program performs a similar function for the pressure sensor channel, using the pressure frequency coefficient to convert each pressure frequency to the frequency at the reference temperature and calculating the pressures using the pressure frequency calibration. The data values, generally at 15 minute intervals, but occasionally at 10 minute intervals, of pressure are then plotted and stored. If waterhead is required, it may be computed by subtracting atmospheric pressure and applying the hydrostatic relation:-

H = P / ( d * g )
H = waterhead (cm)
P = pressure (0.01 mb)
d = density (kg/m3)
g = gravitational acceleration (m/s2)

Station B (North Sea) Data Processing Notes

Clock gained 4 seconds over 59 days, 22.75 hours; the cycle interval and time values have been corrected.

Instrument Characteristics and Calibration Factors

Aanderaa Current meter/Pressure recorder, sensor DIG 4132

Original sampling interval 15 minutes
Integration period 900s
Temperature coefficient 0.0mb/°C
Pressure sensitivity at 8.770°C 0.120Hz/mb

Project Information

IOS North Sea Experiment 1981

An experiment was carried out by I.O.S. Bidston in the North Sea during May and June 1981. The scientific objectives were:

  1. To investigate the slope of the mean sea level surface between Leith and Immingham.
  2. To study the tidal energy budget in a shallow coastal region.
  3. To measure currents around a sandbank to test theories of spring neap changes in the mean currents.

24 rigs containing recording current meters, thermistor chains or pressure recorders were deployed for 40 days at 15 stations. Data from nearby coastal tide gauges were also used. The density field was measured during both the deployment and recovery legs by continuous monitoring of sea surface temperature and conductivity and by recording CTD profiles.

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:

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

SeaDataNet Quality Control Flags

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

Flag Description
0 no quality control
1 good value
2 probably good value
3 probably bad value
4 bad value
5 changed value
6 value below detection
7 value in excess
8 interpolated value
9 missing value
A value phenomenon uncertain