Search the data

Metadata Report for BODC Series Reference Number 1081343

Metadata Summary

Data Description

Data Category CTD or STD cast
Instrument Type
Sea-Bird SBE 911plus CTD  CTD; water temperature sensor; salinity sensor
Sea-Bird SBE 3plus (SBE 3P) temperature sensor  water temperature sensor
Sea-Bird SBE 4C conductivity sensor  salinity sensor
Instrument Mounting lowered unmanned submersible
Originating Country Canada
Originator Dr Igor Yashayaev
Originating Organization Bedford Institute of Oceanography
Processing Status banked
Online delivery of data Download available - Ocean Data View (ODV) format
Project(s) RAPID-WAVE

Data Identifiers

Originator's Identifier HUD2008037/CTD/22
BODC Series Reference 1081343

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2008-10-10 01:07
End Time (yyyy-mm-dd hh:mm) 2008-10-10 02:07
Nominal Cycle Interval 1.0 decibars

Spatial Co-ordinates

Latitude 42.48250 N ( 42° 28.9' N )
Longitude 61.42480 W ( 61° 25.5' W )
Positional Uncertainty 0.05 to 0.1 n.miles
Minimum Sensor or Sampling Depth 3.97 m
Maximum Sensor or Sampling Depth 2734.09 m
Minimum Sensor or Sampling Height 0.0 m
Maximum Sensor or Sampling Height 2730.12 m
Sea Floor Depth 2734.09 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 Approximate - Depth is only approximate


BODC CODERankUnitsTitle
ACYCAA011DimensionlessSequence number
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
PSALCC011DimensionlessPractical salinity of the water body by CTD and computation using UNESCO 1983 algorithm and calibration against independent measurements
SIGTPR011Kilograms per cubic metreSigma-theta of the water body by CTD and computation from salinity and potential temperature using UNESCO algorithm
TEMPCC011Degrees CelsiusTemperature of the water body by CTD and verification against independent measurements

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

Open 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.

If the Information Provider does not provide a specific attribution statement, or if you are using Information from several Information Providers and multiple attributions are not practical in your product or application, you may consider using the following:

"Contains public sector information licensed under the Open Government Licence v1.0."

Narrative Documents

HUD08037 Leg2 CTD Instrumentation

CTD unit and auxiliary sensors

Two Sea-Bird 9 plus CTD systems were used on cruise HUD08037 Leg2. The first package was lost whilst bringing the instrumentation back onboard following cast 14. The second package was used for the remainder of the cruise. The header information in the source CTD data files indicates that the original CTD was fitted with the following scientific sensors:

Sensor Serial Number Last calibration date
Primary Temperature Sensor 032298 16 January 2008
Primary Conductivity Sensor 1873 16 January 2008
Pressure-Digiquartz 69009 25 February 2008
Secondary Temperature Sensor 031423 22 January 2008
Secondary Conductivity Sensor 1125 22 January 2008
Primary Sea-Bird SBE 43 oxygen sensor 430042 10 February 1997
Secondary Sea-Bird SBE 43 oxygen sensor 430133 21 January 2006
Chelsea Aquatracka Mk III (chlorophyll a) fluorometer 088172 10 February 1997
Wetlabs Fluorometer WSCD-987P 18 August 2003
Licor 193SA PAR sensor SPQA2711-LI-193SA 17 June 1999
SBE35 Temperature Sensor unknown unknown

The header information in the source CTD data files indicates that the replacement CTD package was fitted with the following scientific sensors:

Sensor Serial Number Last calibration date
Primary Temperature Sensor 1638 28 January 2008
Primary Conductivity Sensor 1375 29 February 2008
Pressure-Digiquartz 50601 22 February 2008
Secondary Temperature Sensor 032303 22 January 2008
Secondary Conductivity Sensor 1874 17 July 2008
SBE35 Temperature Sensor unknown unknown

Sea-Bird Electronics SBE 911 and SBE 917 series CTD profilers

The SBE 911 and SBE 917 series of conductivity-temperature-depth (CTD) units are used to collect hydrographic profiles, including temperature, conductivity and pressure as standard. Each profiler consists of an underwater unit and deck unit or SEARAM. Auxiliary sensors, such as fluorometers, dissolved oxygen sensors and transmissometers, and carousel water samplers are commonly added to the underwater unit.

Underwater unit

The CTD underwater unit (SBE 9 or SBE 9 plus) comprises a protective cage (usually with a carousel water sampler), including a main pressure housing containing power supplies, acquisition electronics, telemetry circuitry, and a suite of modular sensors. The original SBE 9 incorporated Sea-Bird's standard modular SBE 3 temperature sensor and SBE 4 conductivity sensor, and a Paroscientific Digiquartz pressure sensor. The conductivity cell was connected to a pump-fed plastic tubing circuit that could include auxiliary sensors. Each SBE 9 unit was custom built to individual specification. The SBE 9 was replaced in 1997 by an off-the-shelf version, termed the SBE 9 plus, that incorporated the SBE 3 plus (or SBE 3P) temperature sensor, SBE 4C conductivity sensor and a Paroscientific Digiquartz pressure sensor. Sensors could be connected to a pump-fed plastic tubing circuit or stand-alone.

Temperature, conductivity and pressure sensors

The conductivity, temperature, and pressure sensors supplied with Sea-Bird CTD systems have outputs in the form of variable frequencies, which are measured using high-speed parallel counters. The resulting count totals are converted to numeric representations of the original frequencies, which bear a direct relationship to temperature, conductivity or pressure. Sampling frequencies for these sensors are typically set at 24 Hz.

The temperature sensing element is a glass-coated thermistor bead, pressure-protected inside a stainless steel tube, while the conductivity sensing element is a cylindrical, flow-through, borosilicate glass cell with three internal platinum electrodes. Thermistor resistance or conductivity cell resistance, respectively, is the controlling element in an optimized Wien Bridge oscillator circuit, which produces a frequency output that can be converted to a temperature or conductivity reading. These sensors are available with depth ratings of 6800 m (aluminium housing) or 10500 m (titanium housing). The Paroscientific Digiquartz pressure sensor comprises a quartz crystal resonator that responds to pressure-induced stress, and temperature is measured for thermal compensation of the calculated pressure.

Additional sensors

Optional sensors for dissolved oxygen, pH, light transmission, fluorescence and others do not require the very high levels of resolution needed in the primary CTD channels, nor do these sensors generally offer variable frequency outputs. Accordingly, signals from the auxiliary sensors are acquired using a conventional voltage-input multiplexed A/D converter (optional). Some Sea-Bird CTDs use a strain gauge pressure sensor (Senso-Metrics) in which case their pressure output data is in the same form as that from the auxiliary sensors as described above.

Deck unit or SEARAM

Each underwater unit is connected to a power supply and data logging system: the SBE 11 (or SBE 11 plus) deck unit allows real-time interfacing between the deck and the underwater unit via a conductive wire, while the submersible SBE 17 (or SBE 17 plus) SEARAM plugs directly into the underwater unit and data are downloaded on recovery of the CTD. The combination of SBE 9 and SBE 17 or SBE 11 are termed SBE 917 or SBE 911, respectively, while the combinations of SBE 9 plus and SBE 17 plus or SBE 11 plus are termed SBE 917 plus or SBE 911 plus.


Specifications for the SBE 9 plus underwater unit are listed below:

Parameter Range Initial accuracy Resolution at 24 Hz Response time
Temperature -5 to 35°C 0.001°C 0.0002°C 0.065 sec
Conductivity 0 to 7 S m-1 0.0003 S m-1 0.00004 S m-1 0.065 sec (pumped)
Pressure 0 to full scale (1400, 2000, 4200, 6800 or 10500 m) 0.015% of full scale 0.001% of full scale 0.015 sec

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

HUD08037 Leg2 CTD Originator Processing

Sampling Strategy

A total of 31 CTD casts were performed during cruise HUD08037 Leg2. Niskin bottles were attached to the CTD frame and used to collect water samples at selected depths on stations throughout the cruise. Nine of these casts were performed at the RAPID mooring sites and, consequently, data from these stations were incorporated into the UK RAPID WAVE dataset.

Upon completion of Cast 14, the CTD package was lost overboard during recovery. A replacement package was used for the remainder of the cruise.

Data Processing

Following the completion of each CTD cast the data were processed using SBE Seasave v7.14c software.

The WILDEDIT program was run to remove any large pressure spikes and FILTER was run on the pressure channel. The program ALIGNCTD was run to advance the oxygen measurements by 8 seconds and regress conductivity measurements by 0.01 seconds. CELLTM was then run on the data, followed by DERIVE to produce salinity data, SPLIT, LOOPEDIT (which was run with a minimum CTD velocity of 0.05 m/s), WILDEDIT and BINAVG to produce 1db bin averaged .ODF files.


Oxygen values were calibrated by the data originator by adding a polynomial function of pressure, oxygen and temperature to its values at all pressure levels.

Discrete salinity data from each leg of the cruise were used by the data originator to calibrate CTD salinity data. Salinity samples taken from the CTD bottles were merged with reprocessed CTD data at bottle trip depths with the data originator running a script to determine the required corrections for CTD conductivity and salinity channels. Due to a significant drop in water sample data quality between the first and second legs of the cruise, casts contributing to the RAPID WAVE dataset were calibrated independently from non-RAPID data. These corrections were applied to data in the relevant .ODF files, with additional corrections being applied by adding a polynomial function of pressure at all pressure levels.


Cruise Report for The Hudson Mission HUD 2008-037

HUD08037 Leg2 CTD Processing undertaken by BODC

19 CTD casts spanning all three legs of the cruise were submitted to BODC for inclusion in the RAPID WAVE dataset. These were supplied as 38 .ODF files containing 1 db bin averaged data, split into up and down profiles for each cast. In total, nine of the casts were from the second leg of the cruise.

The downcasts were reformatted to BODC's internal (.qxf) format, a subset of NetCDF. The data originator specifically recommended using data from the secondary conductivity sensor obtained from the replacement CTD package (cast 15 onwards). There were no reported differences in data quality between primary and secondary conductivity from the first CTD package. The originator also noted that secondary oxygen sensor data were preferable across the three legs of the cruise. Data from the secondary sensors, where available, were therefore preferentially retained in the BODC banked dataset and the primary temperature, salinity and oxygen channels were dropped.

The following tables show the mapping of variables within the originator ASCII files to appropriate BODC parameter codes for channels contained in the RAPID WAVE banked series.

Leg2 until Cast 14 (inclusive):

Originator's Variable Units BODC Parameter Code Units Comments
PRES_01 dbar PRESPR01 dbar -
TEMP_02 °C TEMPCC01 °C Checked against data from SBE35. It should be noted that temperature was recorded on the ITS-68 scale.
PSAL_02 - PSALCC01 - Calibrated by data originator using discrete water samples from the CTD bottles.
FC_01 ug l-1 CPHLPM01 mg m-3 -
FWETLABS_01 mg m-3 CPHLPM02 mg m-3 -
DOXY_02 ml l-1 DOXYSU01 µmol l-1 Data converted from ml l-1 to µmol l-1 by multiplying by 44.658
PSAR_01 MicroEinsteins per square metre per second SCIRR4PI MicroEinsteins per square metre per second -
- - POTMCV01 °C Channel derived at BODC
- - SIGTPR01 kg m-3 Channel derived at BODC

Leg2 post Cast 14:

Originator' Variable Units BODC Parameter Code Units Comments
prDM dbar PRESPR01 dbar -
t168C °C TEMPCC01 °C Checked against data from SBE35. It should be noted that temperature was recorded on the ITS-68 scale
sal11 - PSALCC01 - Calibrated by data originator using discrete water samples from the CTD bottles.
- - POTMCV01 °C Channel derived at BODC
- - SIGTPR01 kg m-3 Channel derived at BODC

The reformatted data were visualised using the in-house EDSERPLO software. Suspect data were marked by adding an appropriate quality control flag, and missing data marked by both setting the data to an appropriate value and setting the quality control flag.

Project Information

RAPID Western Atlantic Variability Experiment (WAVE)


The RAPID WAVE project began in 2004 as an observational component of the U.K Natural Environment Research Council's RAPID Climate Change Programme in the western North Atlantic Ocean. In 2008, funding to continue RAPID WAVE was secured through the continuation programme, RAPID-WATCH, which is due to end in 2014.

The RAPID WAVE team brings together scientists at the National Oceanography Centre in Liverpool. Between 2004 and 2010, the RAPID WAVE team also contributed to the Line W mooring array, joining colleagues from the U.S. Line W is a U.S-led initiative used to monitor the North Atlantic Ocean's deep western boundary current whilst being funded through the U.S National Science Foundation and has been active since October 2001. It brings together scientists from Woods Hole Oceanographic Institution (WHOI) and Lamont-Doherty Earth Observatory (LDEO). Users of these data are referred to the Line W Project Website for more information.

In 2007, further collaboration was established with scientists at the Bedford Institute of Oceanography (BIO). This arrangement was formalised and continues under RAPID-WATCH. Smaller scale collaboration with scientists at the Instituto Espanol de Oceanografia (IEO) during RAPID-WATCH saw additional RAPID WAVE observational work in the eastern North Atlantic Ocean. This work commenced in 2009 as part of the RAPID WAVE RAPIDO campaign.

Scientific Rationale

The primary aim of the RAPID WAVE project is to develop an observing system that will identify the propagation of overturning signals, from high to low latitudes, along the western margin of the North Atlantic. It specifically aims to monitor temporal changes in the Deep Western Boundary Current and reveal how coherent the changes are along the slope. Ultimately it is envisaged that this will enable scientists to develop a better understanding of larger-scale overturning circulation in the Atlantic, and its wider impacts on climate.


The fieldwork aspect of the project was to deploy arrays of Bottom Pressure Recorders (BPRs) and CTD moorings along specified satellite altimeter groundtracks off the eastern continental slope of Canada and the United States. In 2004, fieldwork focused on three array lines. Line A was established heading south west from the Grand Banks, whilst the Line B array ran south east on the continental slope of Nova Scotia. The third line, Line W, was an established hydrographic array on the continental slope of New England, serviced by Woods Hole Oceanographic Institute (WHOI), to which RAPID WAVE contributed BPR instrumentation.

The original intention was that each array would be serviced by a cruise every two years. However, following a very poor return rate of instrumentation during the first servicing cruise of Lines A and B in 2006, this plan was modified significantly, and the decision made to abandon work on Line A. In 2007, additional logistical support from Canada's Bedford Institute of Oceanography (BIO) enabled Line B to be serviced again after just one year of deployment, with a much improved recovery record.

The transition from RAPID to RAPID-WATCH funding marked significant changes to the RAPID WAVE observational system. Line B was abandoned and a joint array with BIO, known as the RAPID Scotia Line, to the south west was developed. This line receives annual servicing by BIO, with cruise participation from the RAPID WAVE team.

The servicing of RAPID WAVE BPRs on Line W remained a biennial activity during the RAPID and RAPID-WATCH programmes.

A small number of BPR deployments have also taken place off the coast of Spain as part of the RAPIDO element of RAPID WAVE.


Types of instruments and measurements:

  • Moored BPRs
  • Moored CTD/CT loggers
  • Moored current meters (RAPID-WATCH)
  • Moored ADCPs (RAPID-WATCH)
  • Shipboard measurements: CTD, underway, salinity, LADCP, ADCP


Collaborator Organisation Project
Prof. Chris M. Hughes National Oceanography Centre, U.K RAPID WAVE
Dr. Miguel Angel Morales Maqueda National Oceanography Centre, U.K RAPID WAVE
Dr. Shane Elipot National Oceanography Centre, U.K RAPID WAVE
Dr. John M. Toole Woods Hole Oceanographic Institution, U.S Line W
Dr. Igor Yashayaev Bedford Institute of Oceanography, Canada -

RAPID- Will the Atlantic Thermohaline Circulation Halt? (RAPID-WATCH)

RAPID-WATCH (2007-2014) is a continuation programme of the Natural Environment Research Council's (NERC) Rapid Climate Change (RAPID) programme. It aims to deliver a robust and scientifically credible assessment of the risk to the climate of UK and Europe arising from a rapid change in the Atlantic Meridional Overturning Circulation (MOC). The programme will also assess the need for a long-term observing system that could detect major MOC changes, narrow uncertainty in projections of future change, and possibly be the start of an 'early warning' prediction system.

The effort to design a system to continuously monitor the strength and structure of the North Atlantic MOC is being matched by comparative funding from the US National Science Foundation (NSF) for the existing collaborations started during RAPID for the observational arrays.

Scientific Objectives

  • To deliver a decade-long time series (2004-2014) of calibrated and quality-controlled measurements of the Atlantic MOC from the RAPID-WATCH arrays.
  • To exploit the data from the RAPID-WATCH arrays and elsewhere to determine and interpret recent changes in the Atlantic MOC, assess the risk of rapid climate change, and investigate the potential for predictions of the MOC and its impacts on climate.

This work will be carried out in collaboration with the Hadley Centre in the UK and through international partnerships.

Mooring Arrays

The RAPID-WATCH arrays are the existing 26°N MOC observing system array (RAPIDMOC) and the WAVE array that monitors the Deep Western Boundary Current. The data from these arrays will work towards meeting the first scientific objective.

The RAPIDMOC array consists of moorings focused in three geographical regions (sub-arrays) along 26.5° N: Eastern Boundary, Mid-Atlantic Ridge and Western Boundary. The Western Boundary sub-array has moorings managed by both the UK and US scientists. The other sub-arrays are solely led by the UK scientists. The lead PI is Dr Stuart Cunningham of the National Oceanography Centre, Southampton, UK.

The WAVE array consists of one line of moorings off Halifax, Nova Scotia. The line will be serviced in partnership with the Bedford Institute of Oceanography (BIO), Halifax, Canada. The lead PI is Dr Chris Hughes of the Proudman Oceanographic Laboratory, Liverpool, UK.

All arrays will be serviced (recovered and redeployed) either on an annual or biennial basis using Research Vessels from the UK, US and Canada.

Modelling Projects

The second scientific objective will be addressed through numerical modelling studies designed to answer four questions:

  • How can we exploit data from the RAPID-WATCH arrays to obtain estimates of the MOC and related variables?
  • What do the observations from the RAPID-WATCH arrays and other sources tell us about the nature and causes of recent changes in the Atlantic Ocean?
  • What are the implications of RAPID-WATCH array data and other recent observations for estimates of the risk due to rapid change in the MOC?
  • Could we use RAPID-WATCH and other observations to help predict future changes in the MOC and climate?

Data Activity or Cruise Information


Cruise Name HUD08037 Leg2
Departure Date 2008-10-07
Arrival Date 2008-10-13
Principal Scientist(s)Erica J Head (Bedford Institute of Oceanography)
Ship CCGS Hudson

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