Metadata Report for BODC Series Reference Number 925469
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
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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 | 28/12/2006 |
Temperature | Falmouth Scientific Inc. | NXIC | 2061 | 28/12/2006 |
Conductivity | Falmouth Scientific Inc. | NXIC | 2061 | 28/12/2006 |
BODC Processing
Data were received by BODC in one ASCII format file that was subsequently split into 15 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 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 15 CTD casts were performed on FRV Alba na Mara cruise 1108A part 1 (06 October 2008 - 11 October 2008) in the Firth of Lorn, west Scotland. The CTDs were carried out close to the coast in all cases. The data were collected between 06:00 hours on 09 October and 15:00 hours on 10 October 2008.
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 | 1108A Part 1 |
Departure Date | 2008-10-06 |
Arrival Date | 2008-10-11 |
Principal Scientist(s) | Bill Turrell (Fisheries Research Services Aberdeen Marine Laboratory) |
Ship | FRV Alba Na Mara |
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
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 |
B | nominal value |
Q | value below limit of quantification |