Metadata Report for BODC Series Reference Number 34278


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 8014/980/223
BODC Series Reference 34278
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 1980-08-10 16:30
End Time (yyyy-mm-dd hh:mm) 1980-11-24 05:30
Nominal Cycle Interval 3600.0 seconds
 

Spatial Co-ordinates

Latitude 34.21330 N ( 34° 12.8' N )
Longitude 28.90990 W ( 28° 54.6' W )
Positional Uncertainty 0.1 to 0.5 n.miles
Minimum Sensor Depth 3577.0 m
Maximum Sensor Depth 3577.0 m
Minimum Sensor Height 0.0 m
Maximum Sensor Height 0.0 m
Sea Floor Depth 3577.0 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 Mean sea level - Depth expressed relative to mean sea level as defined by the data originator
Sea Floor Depth Datum Mean sea level - Depth expressed relative to mean sea level as defined by the data originator
 

Parameters

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 Pressure Recorder Type TG-4A

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. 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. The pressure recorder is a deep water instrument and is usually deployed on a pop up mooring.

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 A4 (North Atlantic) Data Processing Notes

Sampling was every 30 minutes, alternate pressure and temperature readings. For the temperature correction, temperature was calculated as a mean of the two adjacent temperatures for each pressure frequency.

Clock lost 34 seconds over 135 days, 14 hours; the cycle interval and time values have been corrected.

Instrument Characteristics and Calibration Factors

Aanderaa Pressure Recorder TG-4A, sensor DIG, serial number 281

Original sampling interval 60 minutes
Integration period 27s
Temperature coefficient 21.68counts/°C
Pressure sensitivity(at 0.964°C) 0.3086counts/mb

To convert pressure to elevation the following values should be used:

Density no CTD casts
Gravitational acceleration constant 9.797m/s 2

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