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Metadata Report for BODC Series Reference Number 888899

Metadata Summary

Data Description

Data Category CTD or STD cast
Instrument Type
Neil Brown MK3 CTD  CTD; water temperature sensor; salinity sensor; dissolved gas sensors
Unknown chlorophyll fluorometer  fluorometers
Unknown transmissometer  transmissometers
Instrument Mounting research vessel
Originating Country Spain
Originator Dr Manuel Varela
Originating Organization Spanish Institute of Oceanography, La Coruna Oceanographic Centre
Processing Status banked
Online delivery of data Download available - Ocean Data View (ODV) format
Project(s) OMEX II-II

Data Identifiers

Originator's Identifier CTD22
BODC Series Reference 888899

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 1999-10-19 07:38
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval 1.0 decibars

Spatial Co-ordinates

Latitude 42.99350 N ( 42° 59.6' N )
Longitude 9.30300 W ( 9° 18.2' W )
Positional Uncertainty 0.0 to 0.01 n.miles
Minimum Sensor or Sampling Depth 4.46 m
Maximum Sensor or Sampling Depth 38.19 m
Minimum Sensor or Sampling Height -0.18 m
Maximum Sensor or Sampling Height 33.54 m
Sea Floor Depth 38.0 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


BODC CODERankUnitsTitle
ATTNZR011per metreAttenuation (red light wavelength) per unit length of the water body by transmissometer
CPHLPR011Milligrams per cubic metreConcentration of chlorophyll-a {chl-a CAS 479-61-8} per unit volume of the water body [particulate >unknown phase] by in-situ chlorophyll fluorometer
DOXYPR011Micromoles per litreConcentration of oxygen {O2 CAS 7782-44-7} per unit volume of the water body [dissolved plus reactive particulate phase] by in-situ Beckmann probe
OXYSBB011PercentSaturation of oxygen {O2 CAS 7782-44-7} in the water body [dissolved plus reactive particulate phase] by in-situ Beckmann probe and computation from concentration using Benson and Krause algorithm
POATCV011per metrePotential attenuance (unspecified wavelength) per unit length of the water body by transmissometer and computation using P-EXEC algorithm
POTMCV011Degrees CelsiusPotential temperature of the water body by computation using UNESCO 1983 algorithm
PRESPR011DecibarsPressure (spatial coordinate) exerted by the water body by profiling pressure sensor and correction to read zero at sea level
PSALST011DimensionlessPractical salinity of the water body by CTD and computation using UNESCO 1983 algorithm
SIGTPR011Kilograms per cubic metreSigma-theta of the water body by CTD and computation from salinity and potential temperature using UNESCO algorithm
TEMPST011Degrees CelsiusTemperature 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

Neil Brown MK3 CTD

The Neil Brown MK3 conductivity-temperature-depth (CTD) profiler consists of an integral unit containing pressure, temperature and conductivity sensors with an optional dissolved oxygen sensor in a pressure-hardened casing. The most widely used variant in the 1980s and 1990s was the MK3B. An upgrade to this, the MK3C, was developed to meet the requirements of the WOCE project.

The MK3C includes a low hysteresis, titanium strain gauge pressure transducer. The transducer temperature is measured separately, allowing correction for the effects of temperature on pressure measurements. The MK3C conductivity cell features a free flow, internal field design that eliminates ducted pumping and is not affected by external metallic objects such as guard cages and external sensors.

Additional optional sensors include pH and a pressure-temperature fluorometer. The instrument is no longer in production, but is supported (repair and calibration) by General Oceanics.


These specification apply to the MK3C version.

Pressure Temperature Conductivity

6500 m

3200 m (optional)

-3 to 32°C 1 to 6.5 S cm-1

0.0015% FS

0.03% FS < 1 msec


0.003°C < 30 msec

0.0001 S cm-1

0.0003 S cm-1 < 30 msec

Further details can be found in the specification sheet.

RV Thalassa 1099 CTD Data Documentation

Instrumentation and Shipboard Procedures

The CTD profiles were taken with a Neil Brown Systems Mk IIIB CTD including pressure, conductivity, temperature and dissolved oxygen sensors. A fluorometer and a transmissometer (type and path length unknown) were also included in the CTD package. A 24-position General Oceanics rosette with 12-litre Niskin bottles was fitted to the CTD frame to collect water samples.

Data Acquisition and On-board Processing

The data supplied to BODC conformed to the expected output format from the standard EG&G acquisition and processing software used with Neil Brown instruments. The data were supplied as 1-decibar binned values, labelled with the pressures of the midpoints of the bins. The transmissometer values were obviously raw voltages. The data from ST0898 included fluorometer data in the form of nominal chlorophyll concentrations. It has been assumed that the data from this cruise are also supplied as nominal chlorophyll concentrations.

Post-cruise Processing

Reformatting and Editing

The data were supplied to BODC as ASCII files, which were converted into the BODC internal format. Each profile was examined using an in-house graphical editing tool and any spikes observed in the data were flagged as suspect. Flags were also applied to the cycle number channel that indicated the start and end of the profile downcast. Twenty five screened downcasts were loaded into the Oracle relational database management system. These were later migrated to the National Oceanographic Database.



No air-logged data were included in the data set. Consequently, the accuracy of the originator's pressure calibration could not be checked. The instrument was reported as calibrated in June 1999. There was no evidence of significant errors in the pressure values.


No reversing thermometer data were available and consequently the originator's calibration could not be checked. The instrument was reported as calibrated in June 1999. There was no evidence of significant errors in the temperature values.


No salinity sample data were taken on this cruise. However, a calibration data set, based on Autosal bottle salinity determinations, was made available from the second (non-OMEX) leg of this cruise. The overall calibration for this cruise leg was an offset of -0.044 (N=42, SD=0.020). This calibration has been applied to the data.

There is strong evidence from this calibration data set of drift in the CTD conductivity sensor, which can be seen in the variation of the individual cast calibrations:

CTD40  27/10/1999  Offset = -0.056  SD = 0.008
CTD77  31/10/1999  Offset = -0.021  SD = 0.007
CTD78  31/10/1999  Offset = -0.024  SD = 0.007
CTD102  05/11/1999  Offset = -0.062  SD = 0.008

The uncertainty in the calibration is relatively high, so the data from this cruise should not be used for applications that require top quality data. However, the calibration quantifies the accuracy of the data and consequently they may be used with confidence for some purposes.

Note that the deepest cast from this cruise was 500m. Consequently, theta-salinity plots couldn't be used to improve the quality of the salinity calibration.


The data supplied had values in the range 4.38 to 4.82, which are the values one would associate with transmissometer output values. Inspection of the data showed that the high values were associated with 'clear water', which confirmed that the data were voltages and not attenuance values.

The optical path length of the transmissometer was not supplied with the data. A simple modelling exercise showed that the only path length out of 5, 10, 20, 25 and 100 cm that gave anything like sensible attenuance values was 10cm. Consequently, a 10cm path length was assumed and the following equation was used to convert voltage to attenuance:

Attenuance = -10.0 * ln (Voltage/5.0)

This resulted in attenuance values spanning the range from 0.375 to 1.541, which are of the correct order of magnitude for the OMEX II box.

No air correction data were available. A nominal air correction of -0.025 per metre was applied to the data, normalising the data to a clear water minimum value of 0.35 per m.

The data from the deep (500m) casts show a trend of increasing attenuance at depth as the cruise progresses. This is believed to be an artefact, but no attempt has been made to correct it.


There were no oxygen bottle data from this cruise. Normal BODC practice in such cases is to delete the CTD oxygen data from the data set. However, visual examination of the data gave the overall impression that the profiles were reasonable and it was considered worthwhile to produce a qualitative data set.

The data supplied were obviously not in any meaningful units, with data values in the region of 2. Such out of range values can cause all sorts of problems for any bespoke software that is more used to conventional oxygen concentrations. Consequently, the data were scaled to bring them into reasonable range. A scaling factor of 109.6 (based on normalising the data at 500m to data at the same depth from Belgica cruise BG9919) was used, which produces surface saturations in the range 90-100%.

Users should be under no illusion about these data. They are NOT calibrated and should be used for QUALITATIVE purposes only.


The only extracted chlorophyll data set available for this cruise was size-fractionated chlorophyll-a data from a trichromatic spectrophotometric assay. The fluorometer values were regressed against the summed size-fraction values, resulting in the following calibration equation:

Chlorophyll (mg/m3) = Nominal chlorophyll * 0.3937 - 0.01 (n=77, R2= 86.3%)

This has been applied to the data.

Data Binning

The final data set has been binned to give a resolution of 1 decibar.


The salinity data should not be used in high accuracy applications because there is strong evidence for drift between casts of up to 0.02 PSU.

The dissolved oxygen data are NOT calibrated. They should only be used qualitatively.

Project Information

Ocean Margin EXchange (OMEX) II - II


OMEX was a European multidisciplinary oceanographic research project that studied and quantified the exchange processes of carbon and associated elements between the continental shelf of western Europe and the open Atlantic Ocean. The project ran in two phases known as OMEX I (1993-1996) and OMEX II - II (1997-2000), with a bridging phase OMEX II - I (1996-1997). The project was supported by the European Union under the second and third phases of its MArine Science and Technology Programme (MAST) through contracts MAS2-CT93-0069 and MAS3-CT97-0076. It was led by Professor Roland Wollast from Université Libre de Bruxelles, Belgium and involved more than 100 scientists from 10 European countries.

Scientific Objectives

The aim of the Ocean Margin EXchange (OMEX) project was to gain a better understanding of the physical, chemical and biological processes occurring at the ocean margins in order to quantify fluxes of energy and matter (carbon, nutrients and other trace elements) across this boundary. The research culminated in the development of quantitative budgets for the areas studied using an approach based on both field measurements and modeling.

OMEX II - II (1997-2000)

The second phase of OMEX concentrated exclusively on the Iberian Margin, although RV Belgica did make some measurements on La Chapelle Bank whilst on passage to Zeebrugge. This is a narrow-shelf environment, which contrasts sharply with the broad shelf adjacent to the Goban Spur. This phase of the project was also strongly multidisciplinary in approach, covering physics, chemistry, biology and geology.

There were a total of 33 OMEX II - II research cruises, plus 23 CPR tows, most of which were instrumented. Some of these cruises took place before the official project start date of June 1997.

Data Availability

Field data collected during OMEX II - II have been published by BODC as a CD-ROM product, entitled:

  • OMEX II Project Data Set (three discs)

Further descriptions of this product and order forms may be found on the BODC web site.

The data are also held in BODC's databases and subsets may be obtained by request from BODC.

Data Activity or Cruise Information


Cruise Name TH1099
Departure Date 1999-10-13
Arrival Date 1999-10-20
Principal Scientist(s)Manuel Varela (Spanish Institute of Oceanography, La Coruna Oceanographic Centre)
Ship Thalassa

Complete Cruise Metadata Report is available here

Fixed Station Information

Fixed Station Information

Station NameOMEX II-II Repeat Section N
CategoryOffshore route/traverse

OMEX II-II Repeat Section N

Section N was one of ten repeat sections sampled during the Ocean Margin EXchange (OMEX) II-II project between June 1997 and October 1999.

The CTD measurements collected at repeat section N, at the Iberian Margin, lie within a box bounded by co-ordinates 42° 58.2' N, 10° 19.9' W at the southwest corner and 43° 5.3' N, 09° 17.9' W at the northeast corner.

Cruises occupying section N

Cruise Start Date End Date
RRS Charles Darwin 105B 10/06/1997 22/06/1997
RV Belgica 9714C 21/06/1997 30/06/1997
RRS Charles Darwin 110A 23/12/1997 05/01/1998
RRS Charles Darwin 110B 06/01/1998 19/01/1998
RV Belgica 9815C 27/06/1998 07/07/1998
RV Professor Shtokman 0898 01/08/1998 11/08/1998
RV Belgica 9919B 04/09/1999 11/09/1999
RV Belgica 9919C 14/09/1999 18/09/1999
RV Thalassa 1099 13/10/1999 20/10/1999

Related Fixed Station activities are detailed in Appendix 1

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

Appendix 1: OMEX II-II Repeat Section N

Related series for this Fixed Station are presented in the table below. Further information can be found by following the appropriate links.

If you are interested in these series, please be aware we offer a multiple file download service. Should your credentials be insufficient for automatic download, the service also offers a referral to our Enquiries Officer who may be able to negotiate access.

Series IdentifierData CategoryStart date/timeStart positionCruise
866450CTD or STD cast1997-06-10 23:50:0042.99817 N, 9.30333 WRRS Charles Darwin CD105B
866462CTD or STD cast1997-06-11 16:29:0042.99933 N, 9.3975 WRRS Charles Darwin CD105B
866185CTD or STD cast1997-06-11 17:58:0043.00183 N, 9.51683 WRRS Charles Darwin CD105B
866474CTD or STD cast1997-06-11 19:19:0043.00083 N, 9.649 WRRS Charles Darwin CD105B
866486CTD or STD cast1997-06-11 21:37:0042.99883 N, 9.71783 WRRS Charles Darwin CD105B
866197CTD or STD cast1997-06-12 00:57:0042.99783 N, 9.83217 WRRS Charles Darwin CD105B
866498CTD or STD cast1997-06-12 03:09:0042.9865 N, 9.8365 WRRS Charles Darwin CD105B
866505CTD or STD cast1997-06-12 04:46:0042.9995 N, 10.01383 WRRS Charles Darwin CD105B
865796CTD or STD cast1997-06-12 08:20:0043.00083 N, 10.29933 WRRS Charles Darwin CD105B
866517CTD or STD cast1997-06-12 11:53:0042.99833 N, 10.289 WRRS Charles Darwin CD105B
864375CTD or STD cast1997-06-27 02:43:0043.0 N, 9.30367 WRV Belgica BG9714C
864387CTD or STD cast1997-06-27 03:43:0042.997 N, 9.40067 WRV Belgica BG9714C
864399CTD or STD cast1997-06-27 05:05:0043.00283 N, 9.39717 WRV Belgica BG9714C
864406CTD or STD cast1997-06-27 08:47:0043.01017 N, 9.40017 WRV Belgica BG9714C
1851633Water sample data1997-06-27 08:51:0043.01009 N, 9.40022 WRV Belgica BG9714C
864418CTD or STD cast1997-06-27 13:12:0042.997 N, 9.52217 WRV Belgica BG9714C
1851645Water sample data1997-06-27 13:21:0042.997 N, 9.52215 WRV Belgica BG9714C
864431CTD or STD cast1997-06-27 17:10:0043.00283 N, 9.65283 WRV Belgica BG9714C
864443CTD or STD cast1997-06-28 03:00:0043.0025 N, 9.8255 WRV Belgica BG9714C
864455CTD or STD cast1997-06-28 05:07:0043.00333 N, 9.82283 WRV Belgica BG9714C
864467CTD or STD cast1997-06-28 11:29:0042.99883 N, 9.828 WRV Belgica BG9714C
1851657Water sample data1997-06-28 11:33:0042.99875 N, 9.82795 WRV Belgica BG9714C
864479CTD or STD cast1997-06-28 13:46:0042.99567 N, 9.819 WRV Belgica BG9714C
1851669Water sample data1997-06-28 13:50:0042.99567 N, 9.819 WRV Belgica BG9714C
864480CTD or STD cast1997-06-28 20:16:0043.0025 N, 10.00767 WRV Belgica BG9714C
864492CTD or STD cast1997-06-29 02:49:0043.00867 N, 10.297 WRV Belgica BG9714C
864511CTD or STD cast1997-06-29 04:35:0043.002 N, 10.3005 WRV Belgica BG9714C
1851670Water sample data1997-06-29 04:39:0043.00205 N, 10.30057 WRV Belgica BG9714C
864523CTD or STD cast1997-06-29 09:29:0043.00683 N, 10.309 WRV Belgica BG9714C
1851682Water sample data1997-06-29 09:36:0043.00689 N, 10.30892 WRV Belgica BG9714C
864535CTD or STD cast1997-06-29 11:59:0043.00367 N, 10.296 WRV Belgica BG9714C
866831CTD or STD cast1997-12-25 14:58:0043.0105 N, 9.71317 WRRS Charles Darwin CD110A
866911CTD or STD cast1997-12-25 17:00:0043.006 N, 9.64667 WRRS Charles Darwin CD110A
866923CTD or STD cast1997-12-25 18:59:0043.00417 N, 9.51533 WRRS Charles Darwin CD110A
866714CTD or STD cast1997-12-25 21:46:0043.01067 N, 9.4065 WRRS Charles Darwin CD110A
864953CTD or STD cast1998-07-02 05:01:0043.00267 N, 9.39567 WRV Belgica BG9815C
865213CTD or STD cast1998-07-02 06:07:0043.00067 N, 9.4055 WRV Belgica BG9815C
865225CTD or STD cast1998-07-03 04:41:0042.9995 N, 9.65017 WRV Belgica BG9815C
864965CTD or STD cast1998-07-03 05:27:0043.01033 N, 9.66783 WRV Belgica BG9815C
865237CTD or STD cast1998-07-03 07:44:0043.018 N, 9.67117 WRV Belgica BG9815C
865329CTD or STD cast1998-07-03 15:19:0042.9975 N, 9.515 WRV Belgica BG9815C
864977CTD or STD cast1998-07-03 18:08:0043.00117 N, 9.80517 WRV Belgica BG9815C
865249CTD or STD cast1998-07-03 20:34:0043.01333 N, 9.80317 WRV Belgica BG9815C
865250CTD or STD cast1998-07-04 04:43:0043.001 N, 10.304 WRV Belgica BG9815C
864989CTD or STD cast1998-07-04 05:26:0043.0105 N, 10.304 WRV Belgica BG9815C
865262CTD or STD cast1998-07-04 07:39:0043.02 N, 10.309 WRV Belgica BG9815C
865330CTD or STD cast1998-07-04 15:11:0043.00383 N, 10.01867 WRV Belgica BG9815C
865274CTD or STD cast1998-07-04 16:42:0043.035 N, 10.029 WRV Belgica BG9815C
864873CTD or STD cast1998-07-06 07:15:0043.00017 N, 9.39883 WRV Belgica BG9815C
864885CTD or STD cast1998-07-06 08:01:0042.99783 N, 9.40067 WRV Belgica BG9815C
864897CTD or STD cast1998-07-06 11:57:0043.0045 N, 9.6435 WRV Belgica BG9815C
864904CTD or STD cast1998-07-06 14:23:0043.0005 N, 9.5165 WRV Belgica BG9815C
888574CTD or STD cast1998-08-08 14:02:0042.99883 N, 10.298 WProfessor Shtokman OMEX-0898
1685977Water sample data1998-08-08 14:22:0042.99883 N, 10.29808 WProfessor Shtokman OMEX-0898
1685989Water sample data1998-08-08 18:29:0042.99958 N, 10.01758 WProfessor Shtokman OMEX-0898
888586CTD or STD cast1998-08-08 18:41:0042.9995 N, 10.0175 WProfessor Shtokman OMEX-0898
1685990Water sample data1998-08-09 07:27:0042.99967 N, 9.51533 WProfessor Shtokman OMEX-0898
888598CTD or STD cast1998-08-09 08:14:0042.99967 N, 9.51533 WProfessor Shtokman OMEX-0898
1686004Water sample data1998-08-09 11:50:0043.00017 N, 9.71692 WProfessor Shtokman OMEX-0898
888605CTD or STD cast1998-08-09 12:02:0043.00017 N, 9.717 WProfessor Shtokman OMEX-0898
1686016Water sample data1998-08-09 14:52:0042.99942 N, 9.64975 WProfessor Shtokman OMEX-0898
888617CTD or STD cast1998-08-09 15:14:0042.9995 N, 9.64967 WProfessor Shtokman OMEX-0898
1686028Water sample data1998-08-10 07:41:0042.99833 N, 9.30175 WProfessor Shtokman OMEX-0898
888629CTD or STD cast1998-08-10 08:35:0042.99833 N, 9.30167 WProfessor Shtokman OMEX-0898
888630CTD or STD cast1998-08-10 09:28:0042.999 N, 9.4015 WProfessor Shtokman OMEX-0898
1686041Water sample data1998-08-10 09:35:0042.99892 N, 9.40142 WProfessor Shtokman OMEX-0898
880154CTD or STD cast1999-09-04 16:02:0042.99667 N, 9.80917 WRV Belgica BG9919B
880283CTD or STD cast1999-09-04 18:02:0043.00117 N, 9.81717 WRV Belgica BG9919B
880351CTD or STD cast1999-09-05 05:40:0042.9975 N, 9.31983 WRV Belgica BG9919B
880547CTD or STD cast1999-09-05 06:27:0043.00217 N, 9.31883 WRV Belgica BG9919B
880178CTD or STD cast1999-09-05 16:06:0043.00167 N, 9.51133 WRV Belgica BG9919B
880559CTD or STD cast1999-09-06 06:05:0042.9985 N, 9.40883 WRV Belgica BG9919B
880142CTD or STD cast1999-09-06 06:47:0043.00617 N, 9.41133 WRV Belgica BG9919B
880560CTD or STD cast1999-09-06 07:29:0043.00633 N, 9.40783 WRV Belgica BG9919B
880363CTD or STD cast1999-09-10 18:40:0042.9975 N, 10.02017 WRV Belgica BG9919B
880572CTD or STD cast1999-09-10 19:18:0042.99733 N, 10.03283 WRV Belgica BG9919B
880271CTD or STD cast1999-09-11 06:13:0043.00017 N, 9.3195 WRV Belgica BG9919B
880720CTD or STD cast1999-09-14 13:19:0043.0005 N, 9.32333 WRV Belgica BG9919C
888851CTD or STD cast1999-10-18 13:53:0043.0015 N, 10.02083 WThalassa TH1099
888863CTD or STD cast1999-10-18 16:56:0043.00617 N, 9.709 WThalassa TH1099
888875CTD or STD cast1999-10-18 18:36:0042.99817 N, 9.64133 WThalassa TH1099
888887CTD or STD cast1999-10-18 20:53:0042.99467 N, 9.29933 WThalassa TH1099
888906CTD or STD cast1999-10-19 09:06:0043.00067 N, 9.4 WThalassa TH1099
888918CTD or STD cast1999-10-19 11:33:0042.9945 N, 9.51617 WThalassa TH1099