Metadata Report for BODC Series Reference Number 648698

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

Hydrography time series at depth

Instrument Type

Name	Categories
Sea-Bird SBE 37 MicroCat SM-CT with optional pressure (submersible) CTD sensor series	water temperature sensor; salinity sensor

Instrument Mounting

subsurface mooring

Originating Country

United Kingdom

Originator

Ms Sarah Hughes

Originating Organization

Fisheries Research Services Aberdeen Marine Laboratory (now Marine Scotland Aberdeen Marine Laboratory)

Processing Status

banked

Online delivery of data

Download available - Ocean Data View (ODV) format

Project(s)

Data Identifiers

Originator's Identifier	702/2
BODC Series Reference	648698

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm)	2004-05-20 11:35
End Time (yyyy-mm-dd hh:mm)	2005-02-24 14:10
Nominal Cycle Interval	300.0 seconds

Spatial Co-ordinates

Latitude	60.24570 N ( 60° 14.7' N )
Longitude	8.99420 W ( 8° 59.7' W )
Positional Uncertainty	0.05 to 0.1 n.miles
Minimum Sensor or Sampling Depth	1236.0 m
Maximum Sensor or Sampling Depth	1236.0 m
Minimum Sensor or Sampling Height	28.0 m
Maximum Sensor or Sampling Height	28.0 m
Sea Floor Depth	1264.0 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)
PSALPR01	1	Dimensionless	Practical salinity of the water body by conductivity cell and computation using UNESCO 1983 algorithm
TEMPPR01	1	Degrees Celsius	Temperature of the water body

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

The first 11 days' worth of current data were lost as a result of biofouling of the instrument. The speed and direction time series therefore begin with 11 days' worth of null values.

Suspect values were identified during screening where current speed and direction both dropped to zero for two or more consecutive data cycles. This is likely to be the result of temporary fouling of the current meter rotor. These suspect data points have been flagged M. Where a small number of non-zero points occur within a long series of zeroes the non-zero data have also been flagged M as it is unlikely that rotor movement was entirely free for a short number of data cycles before the instrument became jammed again.

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

Sea-Bird SBE 37-SM MicroCAT

The SBE 37-SM MicroCAT is a high accuracy conductivity and temperature recorder (pressure optional). Designed for moorings and other long-duration, fixed-site deployments, MicroCATs have non-corroding titanium housings rated for operation to 7000 metres or pressure sensor full scale-range. Communication with the MicroCAT is over an internal, 3-wire, RS-232C link. The MicroCAT's aged and pressure-protected thermistor has a long history of exceptional accuracy and stability (typical drift is less than 0.002° per year). Electrical isolation of the conductivity electronics eliminates any possibility of ground-loop noise.

Specifications

	Temperature (°C)	Conductivity (S m^-1)	Optional Pressure
Measurement Range	-5 to +35	0 to 7 (0 to 70 mS cm^-1)	0 to full scale range: 20 / 100 / 350 / 1000 / 2000 / 3500 / 7000 metres
Initial accuracy	0.002	0.0003	0.1% of full scale range
Typical Stability	0.0002 per month	0.0003 per month	0.05% of full scale range per year
Resolution	0.0001	0.00001	0.002% of full scale range
Sensor Calibration	+1 to +32	0 to 6; physical calibration over range 2.6 to 6 S m^-1, plus zero conductivity (air)	Ambient pressure to full scale range in 5 steps
Memory	8 Mbyte non-volatile FLASH memory
Data Storage	Converted temperature and conductivity: 6 bytes per sample (3 bytes each) Time: 4 bytes per sample Pressure (optional): 5 bytes per sample
Real-Time Clock	32,768 Hz TCXO accurate to ±1 minutes year^-1
Standard Internal Batteries	Nominal 10.6 Ampere-hour pack consisting of 12 AA lithium batteries. Provides sufficient capacity for more than 630,000 samples for a typical sampling scheme
Housing	Titanium pressure case rated at 7000 metres
Weight (without pressure)	In water: 2.3 kg In air: 3.8 kg

Further information can be found via the following link: SBE 37-SM MicroCAT Datasheet

Originator's Data Processing

Sampling Strategy

The Aanderaa RCM 7 current meter deployed on the Wyville-Thompson Ridge had a sampling frequency of 1 reading per hour and the SeaBird SBE37 MicroCAT had a sampling frequency of 12 readings per hour. The RCM7 included a temperature sensor.

Data Processing

DAF applied the standard manufacturers' calibrations to all current, temperature and salinity data, and produced ASCII files for submission to BODC. Data files were named according to the mooring code (702) and the instrument number (2 or 3). The RCM7 data file (7023) contained eastward and northward velocities, and temperature. The MicroCAT data file (7022) contained temperature data and salinity data were provided in a separate file (append s).

BODC Processing

Data were received by BODC in ASCII format files. This series was reformatted to the internal QXF format using BODC transfer function 325. The following table shows how the variables within the file were mapped to the appropriate BODC parameter codes.

Original parameter name	Original Units	Description	BODC Parameter Code	BODC Units	Comments
Time	DD/MM/YYYY HH:MI	date and time	AADYAA01 and AAFDZZ01	day number and day fraction GMT	Conversion by transfer
T	degrees Celsius	Temperature	TEMPPR01	degrees Celsius
S	dimensionless	Salinity	PSALPR01	dimensionless

Following transfer to QXF, the data were screened using BODC's in-house visualisation software, EDSERPLO. Any data considered as suspect were flagged 'M'. Flags from the originator marking suspect data were retained during transfer and flagged 'L'.

Project Information

No Project Information held for the Series

Data Activity or Cruise Information

Data Activity

Start Date (yyyy-mm-dd)	2004-05-20
End Date (yyyy-mm-dd)	2005-02-24
Organization Undertaking Activity	Fisheries Research Services Aberdeen Marine Laboratory (now Marine Scotland Aberdeen Marine Laboratory)
Country of Organization	United Kingdom
Originator's Data Activity Identifier	702
Platform Category	subsurface mooring

DAF current meter mooring, Wyville-Thompson Ridge

The mooring was located at 60° 14.74' N, 008° 59.65' W in a nominal water depth of 1264 m.

The mooring was deployed on 20 May 2004 by the Department of Agriculture and Fisheries (DAF, now known as Marine Scotland Aberdeen Marine Laboratory) on cruise FRV Scotia 0804S (Part 1) (12 May 2004-30 May 2004), recovered on 24 February 2005, and consisted of the following instruments.

Instrument type	Serial Number	Deployment start	Deployment end	Instrument depth (m)	Comments
SeaBird SBE37 MicroCAT	1389	2004-05-20	2005-02-24	1236
Aanderaa RCM 7	12413	2004-05-20	2005-02-24	1237

Related Data Activity activities are detailed in Appendix 1

Cruise

Cruise Name	0804S_1
Departure Date	2004-05-12
Arrival Date	2004-05-30
Principal Scientist(s)	Bill Turrell (Fisheries Research Services Aberdeen Marine Laboratory)
Ship	FRV Scotia

Complete Cruise Metadata Report is available here

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