Metadata Report for BODC Series Reference Number 898882


Metadata Summary

Data Description

Data Category CTD or STD cast
Instrument Type
NameCategories
Falmouth Scientific Instruments NXIC CTD  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
Project(s) -
 

Data Identifiers

Originator's Identifier LE01/07/13
BODC Series Reference 898882
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2007-07-18 13:34
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval 1.0 decibars
 

Spatial Co-ordinates

Latitude 57.84717 N ( 57° 50.8' N )
Longitude 5.63117 W ( 5° 37.9' W )
Positional Uncertainty 0.05 to 0.1 n.miles
Minimum Sensor Depth 0.99 m
Maximum Sensor Depth 23.78 m
Minimum Sensor Height 1.21 m
Maximum Sensor Height 24.01 m
Sea Floor Depth 25.0 m
Sensor Distribution Variable common depth - All sensors are grouped effectively at the same depth, but this depth varies significantly during the series
Sensor 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 Short Title Title
ACYCAA01 1 Dimensionless Record_No Sequence number
CNDCST01 1 Siemens per metre CTDCond Electrical conductivity of the water body by CTD
PRESPR01 1 Decibars Pres_Z Pressure (spatial co-ordinate) exerted by the water body by profiling pressure sensor and corrected to read zero at sea level
PSALST01 1 Dimensionless P_sal_CTD Practical salinity of the water body by CTD and computation using UNESCO 1983 algorithm
TEMPST01 1 Degrees Celsius WC_temp_CTD 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

The NXIC CTD is a rugged Conductivity-Temperature-Depth profiler that was originally developed for the US Navy DT-705 Sound Velocity/Salinity sensor. It is a fast sampling, full integrated instrument with optional battery power, datalogging and external analog sensor input.

The instrument can be used in rapid profiling and towing applications or can be mounted on AUVs and ROVs. Two depth ratings are available: 500 m (Delrin housing) and 7000 m (titanium housing). The sample rate is user programmable between 1 and 15 Hz with a 20 bit resolution.

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 .

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

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