Metadata Report for BODC Series Reference Number 40966

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) -

Data Identifiers

Originator's Identifier C6AP0/PDFH4
BODC Series Reference 40966

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 1975-09-06 11:37
End Time (yyyy-mm-dd hh:mm) 1975-10-01 08:37
Nominal Cycle Interval 900.0 seconds

Spatial Co-ordinates

Latitude 50.81990 N ( 50° 49.2' N )
Longitude 10.91660 W ( 10° 55.0' W )
Positional Uncertainty 0.1 to 0.5 n.miles
Minimum Sensor Depth 172.0 m
Maximum Sensor Depth 172.0 m
Minimum Sensor Height 0.0 m
Maximum Sensor Height 0.0 m
Sea Floor Depth 172.0 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)
PPSSRL01 1 Decibars RelBotPress 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

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 Pressure Recorder Type TG-2A and WLR-5

Pressure recorder TG-2A (serial number 64) was used until the end of 1979. It was then returned to Aanderaa Instruments Limited who carried out modifications changing it to the specification of an Aanderaa WLR-5. Hence from 1980 onwards the instrument is known as Aanderaa WLR-5 (serial number 500).

The Aanderaa recorder uses a Digiquartz type 2-300a quartz crystal pressure transducer. The pressure sensor consists of a convoluted bellows linked to a 40kHz quartz crystal resonator coupled by piezoelectric action to an electronic resonator. The sensor pack is mounted in a low profile steel tripod frame 0.76m by 1.183m in size with the sensor level approximately 0.48m above the frame base. Data are recorded on to 0.25 inch magnetic tape on an Aanderaa data logger in the same case. A quartz crystal clock is used for controlling the sampling interval.

The data are recorded as 10 bit binary words in serial form with the frequency count from the sensor stored as the most and least significant counts. There is no temperature sensor. The tide gauge 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.

Data Processing Notes

Clock gained 3 seconds over 24 days 20 hours 59 minutes 57 seconds; the cycle interval and time values have been corrected.

Instrument Characteristics

Station C6

Aanderaa 2A/64 (BODC Series Ref. 40966)
Nominal sampling interval 900 seconds
Integration period 104 seconds

This instrument was deployed on the same frame as a Mark II tide gauge.

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.

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