Metadata Report for BODC Series Reference Number 898833

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

CTD or STD cast

Instrument Type

Name	Categories
Falmouth Scientific Instruments NXIC CTD Series	CTD; water temperature sensor; salinity sensor

Instrument Mounting

research vessel

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	LE01/07/8
BODC Series Reference	898833

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm)	2007-07-18 12:19
End Time (yyyy-mm-dd hh:mm)	-
Nominal Cycle Interval	1.0 decibars

Spatial Co-ordinates

Latitude	57.81700 N ( 57° 49.0' N )
Longitude	5.64517 W ( 5° 38.7' W )
Positional Uncertainty	0.05 to 0.1 n.miles
Minimum Sensor or Sampling Depth	0.99 m
Maximum Sensor or Sampling Depth	44.58 m
Minimum Sensor or Sampling Height	1.42 m
Maximum Sensor or Sampling Height	45.01 m
Sea Floor Depth	46.0 m
Sea Floor Depth Source	-
Sensor or Sampling Distribution	Variable common depth - All sensors are grouped effectively at the same depth, but this depth varies significantly during 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
ACYCAA01	1	Dimensionless	Sequence number
CNDCST01	1	Siemens per metre	Electrical conductivity of the water body by CTD
PRESPR01	1	Decibars	Pressure (spatial coordinate) exerted by the water body by profiling pressure sensor and correction to read zero at sea level
PSALST01	1	Dimensionless	Practical salinity of the water body by CTD and computation using UNESCO 1983 algorithm
TEMPST01	1	Degrees Celsius	Temperature of the water body by CTD or STD

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

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

Falmouth Scientific NXIC CTD Series

The FSI NXIC CTD Series is a collection of rugged Conductivity-Temperature-Depth profilers that utilise the patented Non-eXternal Inductive Cell (NXIC) conductivity sensor, which was originally developed for the US Navy DT-705 Sound Velocity/Salinity sensor. The CTDs are fast sampling, fully integrated instruments with optional battery power, datalogging and external analog sensor input.

Models in the collection include the NXIC CT Bio Direct Read-500M, NXIC CTD Bio Direct Read-500M, NXIC CTD Bio Auto-500M, NXIC CTD Direct Read-500M, NXIC CTD Direct Read-700M, NXIC CTD Auto-500M, NXIC CTD Auto-700M, NXIC CTD-ADC with external sensors, and the NXIC ETSG Thermosalinograph. Parameters are measured to an accuracy ranging from 0.002-0.010 mS/cm for conductivity, 0.005 degC for temperature and 0.08% for full scale pressure. Now marketed by Teledyne RD Instruments.

Specifications

	Conductivity	Temperature	Pressure
Sensor type	Inductive cell	Thermistor	Precision-machined Silicon
Range	0 to 9.0 S m^-1	-5 to 45°C	user specified
Accuracy	± 0.0002 S m^-1	± 0.005°C	0.08 % full scale
Stability	± 0.00005 S cm^-1 month^-1	0.0005°C month^-1	± 0.004 %
Resolution	0.00001 S m^-1	0.001°C	0.001 % full scale
Response	5.0 cm at 1 m sec^-1 flow	100 msec	25 msec

Further details can be found in the manufacturer's specification sheet and Series Brochure.

Instrument Description

CTD Unit and Auxiliary Sensors

A Falmouth Scientific Inc. NXIC CTD unit was used. The CTD unit included the following sensors.

Sensor	Manufacturer	Model	Serial number	Calibration date
Pressure	Falmouth Scientific Inc.	NXIC	2061	2006-12-28
Temperature	Falmouth Scientific Inc.	NXIC	2061	2006-12-28
Conductivity	Falmouth Scientific Inc.	NXIC	2061	2006-12-28

BODC Processing

Data were received by BODC in one ASCII format file that was subsequently split into 16 separate files, one for each CTD profile. The series were reformatted to the internal QXF format using BODC transfer function 340. The following table details the mapping of variables to BODC parameter codes.

Original parameter name	Original Units	Description	BODC Parameter Code	BODC Units	Comments
Pressure	Decibars	Pressure exerted by the water column	PRESPR01	Decibars
Temperature	°C	Temperature of the water column	TEMPST01	°C
Conductivity	mS cm^-1	Electrical conductivity of the water column	CNDCST01	S m^-1	Conversion by transfer (mS cm^-1 x 0.1)
Salinity		Salinity of the water column	PSALST01	Dimensionless	Derived by transfer using UNESCO 1983 algorithm

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'.

Originator's Data Processing

Sampling Strategy

A total of 16 CTD casts were performed during a small boat survey of Loch Ewe in northwest Scotland. The data were collected between 09:00 and 15:00 hours during the period 17 July 2007 - 19 July 2007.

Data Processing

The raw CTD data files were processed through the Falmouth Scientific NXIC CTDPro data processing software following standard procedures. The originators used in-house interactive visual display editing software to edit out individual spikes in the primary temperature and conductivity channels. An ASCII file was generated for each CTD cast and all files from a cruise were concatenated into one ASCII file which was submitted to BODC.

Project Information

No Project Information held for the Series

Data Activity or Cruise Information

Cruise

Cruise Name	Loch Ewe 07/01
Departure Date	2007-07-17
Arrival Date	2007-07-19
Principal Scientist(s)	John Beaton (Fisheries Research Services Aberdeen Marine Laboratory)
Ship	Glen Tarff

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