Metadata Report for BODC Series Reference Number 36875

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

Data Description

Data Category

Offshore sea floor pressure series

Instrument Type

Name	Categories
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

Online delivery of data

Download available - Ocean Data View (ODV) format

Project(s)

Data Identifiers

Originator's Identifier	G1DP5/SMDFH0
BODC Series Reference	36875

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm)	1981-12-08 16:00
End Time (yyyy-mm-dd hh:mm)	1982-03-14 02:00
Nominal Cycle Interval	3600.0 seconds

Spatial Co-ordinates

Latitude	26.57680 N ( 26° 34.6' N )
Longitude	43.95910 W ( 43° 57.5' W )
Positional Uncertainty	0.1 to 0.5 n.miles
Minimum Sensor or Sampling Depth	3600.0 m
Maximum Sensor or Sampling Depth	3600.0 m
Minimum Sensor or Sampling Height	0.0 m
Maximum Sensor or Sampling Height	0.0 m
Sea Floor Depth	3600.0 m
Sea Floor Depth Source	-
Sensor or Sampling Distribution	Fixed common depth - All sensors are grouped effectively at the same depth which is effectively fixed for the duration of the series
Sensor or Sampling 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

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 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 11 seconds over 97 days 13 hours 34 minutes 56 seconds; the original cycle interval and time values have been corrected.

Instrument Characteristics

Station	G1
OSTG Mark IV	No. 3
Sensors	SG2/D3 (BODC Series Ref. 36875) DQ5997 (BODC Series Ref. 36887)
Nominal sampling interval	225 secs
Integration period	225 secs
Actual sampling interval	225.001895 secs

IOS Data Processing of Off-Shore Pressure Recorder Data

Data processing consists of two stages:-

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

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:

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