Metadata Report for BODC Series Reference Number 1066334
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Sea-Bird Dissolved Oxygen Sensor SBE 43 and SBE 43F
The SBE 43 is a dissolved oxygen sensor designed for marine applications. It incorporates a high-performance Clark polarographic membrane with a pump that continuously plumbs water through it, preventing algal growth and the development of anoxic conditions when the sensor is taking measurements.
Two configurations are available: SBE 43 produces a voltage output and can be incorporated with any Sea-Bird CTD that accepts input from a 0-5 volt auxiliary sensor, while the SBE 43F produces a frequency output and can be integrated with an SBE 52-MP (Moored Profiler CTD) or used for OEM applications. The specifications below are common to both.
|Housing||Plastic or titanium|
0.5 mil- fast response, typical for profile applications
1 mil- slower response, typical for moored applications
|Depth rating|| |
600 m (plastic) or 7000 m (titanium)
10500 m titanium housing available on request
|Measurement range||120% of surface saturation|
|Initial accuracy||2% of saturation|
|Typical stability||0.5% per 1000 h|
Further details can be found in the manufacturer's specification sheet.
RAPID Cruise CD160 CTD Instrumentation
Two CTD units were used during this cruise, the first of which was lost overboard at station 4A at the end of cast 5. A replacement CTD package, on loan from Bedford Institute of Oceanography (BIO), was used for casts 6 to 10. Both CTD units were Sea-Bird Electronics 911plus systems. Both CTDs had a 24 position Sea-Bird Carousel with 10 litre Ocean Test Equipment bottles attached.
UKORS CTD package (casts 1-5):
|Sensor||Serial number||Last calibration date|
|Digiquartz temperature compensated pressure sensor||78958||17/06/2003|
|Chelsea Alphatracka MKII transmissometer||161-2642-003||05/09/1996|
|Sea-Bird 43 dissolved oxygen sensor||43-0076||18/11/2003|
|Chelsea Aquatracka MKIII fluorometer||088241||01/10/2002|
|Sea-Bird 4 conductivity sensor||04C-2637||17/06/2004|
|Sea-Bird 4 conductivity sensor||04C-2840||10/06/2004|
|Sea-Bird 3 Premium temperature sensor||03P-2758||09/06/2004|
|Sea-Bird 3 Premium temperature sensor||03P-2880||09/06/2004|
|WETLabs/SeaTech Light Scattering sensor||635||-|
|RD Instruments 300 KHz LADCP (downward looking)||3726||-|
|RD Instruments 150 KHz LADCP (downward looking)||1308||-|
BIO CTD package (casts 6-10):
|Sensor||Serial number||Last calibration date|
|Digiquartz temperature compensated pressure sensor||90573||12/02/2003|
|Sea-Bird 4 conductivity sensor||04C-2841||29/06/2004|
|Sea-Bird 4 conductivity sensor||04-1375||07/07/1994|
|Sea-Bird 3 Premium temperature sensor||03P-4301||29/06/2004|
|Sea-Bird 3 temperature sensor||03-1638||06/07/1994|
|Sea-Bird 43 dissolved oxygen sensor||43-0133||24/01/2002|
72 salinity samples from the CTD were analysed during the cruise using 2 Guildline Portasal salinometers (serial numbers 65738 and 62507). Readings were very stable and drift was constant.
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.
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.
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.
RAPID Cruise CD160 CTD Processing
A total of 10 CTD casts were performed during the cruise. During cast 5, the entire CTD package was lost, so downcast data are available, but no upcast or water samples were recovered. Rosette bottles were fired at regular intervals throughout each profile in order to obtain salinity samples for calibration. In addition, samples were taken from the bottles and stored for future analysis of oxygen isotopes and iodine-129.
The raw CTD files were processed by the data originator through the Sea-Bird SBE Data Processing software. Binary (.DAT) files were converted to engineering units and ASCII format (.CNV) using the DATCNV program. The configuration (.CON) file sourced by DATCNV included the coefficients M (19.2953) and B (-0.6368) for casts 1-5, used for calibration of the transmissometer. The original voltages quoted by the manufacturer are as follows: voltage output in pure water = 4.205, air voltage = 4.660, blocked path voltage = 0.027. The transmissometer has a path length of 0.25 m.
The FILTER program (low-pass filter) was run on conductivity (0.03 seconds) and pressure (0.15 seconds) to improve the pressure resolution prior to running LOOPEDIT. ALIGN CTD was run to advance oxygen by 7 seconds (no bottle samples were collected for oxygen analysis so this value was chosen following examination of upcast and downcast profiles by Paul Duncan, UKORS). No conductivity alignment was necessary as the deck unit advanced both sensors by 0.073 seconds (the value specified by Sea-Bird). To compensate for conductivity cell thermal mass effects, the files were run through CELLTM, using alpha = 0.03, 1/beta = 7, typical values for this CTD model given in the Sea-Bird literature. A fixed minimum CTD velocity of 0.25 m s-1 was used for LOOP EDIT in order to exclude scans where the CTD was travelling backwards due to ship's heave. An additional processing step (WILD EDIT) was required for cast 1 to reduce the amount of noise in the profile.
After initial processing using the Sea-Bird software, additional routines were applied in Matlab. Manual despiking of temperature and conductivity was carried out on the Sea-Bird processed files, and subsequently, bottle files were generated containing CTD salinities from the time the bottles were fired. These values were compared with bottle salinity measurements and any outliers were flagged. CTD and bottle salinity were then plotted with depth, in addition to CTD bottle salinity difference with depth. This stage identified the most suitable bottles to derive the offsets required for CTD calibration. The bottle salinity values were converted to conductivities and the offsets applied to the corresponding CTD conductivities. Finally, CTD conductivities were converted back to CTD salinities and potential temperature and density were also calculated. The table below shows the conductivity offsets (mS cm-1) for each cast and sensor.
|Cast||Primary sensor conductivity offset||Secondary sensor conductivity offset|
|1||0.0015||Salinity set to missing, due to noise|
|5||No bottle data available||No bottle data available|
The remaining Matlab routines split the data into upcast and downcast sections (the cut off determined from the maximum pressure reading), and gridded the downcast data into 2 decibar averages. Ultimately, surface layer interpolation was achieved for casts where the CTD was not sufficiently close to the surface at the start of the downcast.
The processed data were supplied as Matlab files to BODC for banking.
BODC post-processing and screening
The data were converted into BODC internal format, a subset of NetCDF, to allow use of in-house visualisation tools. In addition to reformatting, the transfer program applied unit conversions to the oxygen and beam attenuation channels. The following table shows how the variables within the original files were mapped to appropriate parameter codes.
|Parameter||Originator's parameter||Originator's units||BODC Parameter code||BODC units||Number of stations||Comments|
|Pressure||press||dbars||PRESPR01||dbars||10||Manufacturer's calibration applied|
|Conductivity (Primary)||cond1||mS cm-1||N/A||-||10||Not transferred|
|Conductivity (Secondary)||cond2||mS cm-1||N/A||-||10||Not transferred|
|Salinity (Secondary)||sal2||-||N/A||-||10||Channel dropped from final series|
|Temperature (Primary)||temp1||°C||TEMPCU01||°C||10||Manufacturer's calibration applied|
|Temperature (Secondary)||temp2||°C||N/A||-||10||Channel dropped from final series|
|Beam attenuation||trans||%||ATTNMR01||m-1||5||Unit conversion: beam atten = (-1/0.25)*ln(trans/100)|
|Dissolved oxygen||oxy||ml l-1||DOXYSU01||µmol l-1||10||Unit conversion by multiplying by 44.66|
|Oxygen saturation||N/A||-||OXYSSU01||%||10||Regenerated at BODC|
|Oxygen voltage||oxyvolt||V||N/A||-||10||Not transferred|
|Chlorophyll-a||fluor||mg m-3||CPHLPM01||mg m-3||5||Manufacturer's calibration applied|
|Sigma-theta (UNESCO SVAN)||N/A||-||SIGTPR01||Kg m-3||10||Regenerated at BODC using data from primary sensors|
|Potential temperature (UNESCO)||N/A||-||POTMCV01||°C||10||Regenerated at BODC using data from primary sensors|
Reformatted CTD data were transferred onto a graphics workstation for visualisation using the in-house editor EDSERPLO. Downcasts and upcasts were differentiated and the limits flagged.
Once BODC quality control screening was complete, the CTD downcasts were banked in the BODC National Oceanographic Database.
Rapid Climate Change (RAPID) Programme
Rapid Climate Change (RAPID) is a £20 million, six-year (2001-2007) programme of the Natural Environment Research Council (NERC). The programme aims to improve our ability to quantify the probability and magnitude of future rapid change in climate, with a main (but not exclusive) focus on the role of the Atlantic Ocean's Thermohaline Circulation.
- To establish a pre-operational prototype system to continuously observe the strength and structure of the Atlantic Meridional Overturning Circulation (MOC).
- To support long-term direct observations of water, heat, salt, and ice transports at critical locations in the northern North Atlantic, to quantify the atmospheric and other (e.g. river run-off, ice sheet discharge) forcing of these transports, and to perform process studies of ocean mixing at northern high latitudes.
- To construct well-calibrated and time-resolved palaeo data records of past climate change, including error estimates, with a particular emphasis on the quantification of the timing and magnitude of rapid change at annual to centennial time-scales.
- To develop and use high-resolution physical models to synthesise observational data.
- To apply a hierarchy of modelling approaches to understand the processes that connect changes in ocean convection and its atmospheric forcing to the large-scale transports relevant to the modulation of climate.
- To understand, using model experimentation and data (palaeo and present day), the atmosphere's response to large changes in Atlantic northward heat transport, in particular changes in storm tracks, storm frequency, storm strengths, and energy and moisture transports.
- To use both instrumental and palaeo data for the quantitative testing of models' abilities to reproduce climate variability and rapid changes on annual to centennial time-scales. To explore the extent to which these data can provide direct information about the thermohaline circulation (THC) and other possible rapid changes in the climate system and their impact.
- To quantify the probability and magnitude of potential future rapid climate change, and the uncertainties in these estimates.
Overall 38 projects have been funded by the RAPID programme. These include 4 which focus on Monitoring the Meridional Overturning Circulation (MOC), and 5 international projects jointly funded by the Netherlands Organisation for Scientific Research, the Research Council of Norway and NERC.
The RAPID effort to design a system to continuously monitor the strength and structure of the North Atlantic Meridional Overturning Circulation is being matched by comparative funding from the US National Science Foundation (NSF) for collaborative projects reviewed jointly with the NERC proposals. Three projects were funded by NSF.
A proportion of RAPID funding as been made available for Small and Medium Sized Enterprises (SMEs) as part of NERC's Small Business Research Initiative (SBRI). The SBRI aims to stimulate innovation in the economy by encouraging more high-tech small firms to start up or to develop new research capacities. As a result 4 projects have been funded.
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.
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
|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||-|
|Principal Scientist(s)||Mike Meredith (Proudman Oceanographic Laboratory)|
|Ship||RRS Charles Darwin|
Complete Cruise Metadata Report is available here
Fixed Station Information
|Station Name||RAPID WAVE Site B3|
|Latitude||42° 36.00' N|
|Longitude||60° 36.00' W|
|Water depth below MSL||3200.0 m|
RAPID Mooring Site B3
This fixed station forms part of the Line B mooring array located to the east of Halifax, Nova Scotia, deployed as part of the RAPID WAVE project.
|Period of collection||August 2004 - October 2008|
|Mooring identifier||Mooring type||Deployment date||Recovery date||Parameters measured|
|B3RL#1 *||RapidLander||21 Aug 2004||02 Aug 2006||Pressure and temperature|
|B3LM#1 **||Line Mooring||19 Aug 2004||-||Temperature, conductivity, salinity and pressure|
|B3LM#2||Line Mooring||09 Aug 2006||06 Oct 2007||Temperature, conductivity, salinity, pressure and currents|
|B3LM#3||Line Mooring||07 Oct 2007||29 Sep 2008||Temperature, conductivity, salinity, pressure and currents|
* Incorporated an Inverted Echo Sounder (IES)
** Mooring lost
Related Fixed Station activities are detailed in Appendix 1
The following single character qualifying flags may be associated with one or more individual parameters with a data cycle:
|<||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.)|
|E||End of CTD Down/Up Cast|
|G||Non-taxonomic biological characteristic uncertainty|
|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|
|O||Improbable value - user quality control|
The following single character qualifying flags may be associated with one or more individual parameters with a data cycle:
|0||no quality control|
|2||probably good value|
|3||probably bad value|
|6||value below detection|
|7||value in excess|
|A||value phenomenon uncertain|
|Q||value below limit of quantification|
Appendix 1: RAPID WAVE Site B3
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 Identifier||Data Category||Start date/time||Start position||Cruise|
|1040780||Offshore sea floor pressure series||2004-08-21 17:52:30||42.62008 N, 60.61208 W||RRS Charles Darwin CD160|
|1070124||CTD or STD cast||2006-08-04 22:35:00||42.64 N, 60.68333 W||RRS Discovery D308|
|938413||Hydrography time series at depth||2006-08-09 14:02:22||42.6 N, 60.625 W||RRS Discovery D308|
|938517||Hydrography time series at depth||2006-08-09 14:03:35||42.6 N, 60.625 W||RRS Discovery D308|
|938401||Hydrography time series at depth||2006-08-09 14:04:50||42.6 N, 60.625 W||RRS Discovery D308|
|938505||Hydrography time series at depth||2006-08-09 14:05:59||42.6 N, 60.625 W||RRS Discovery D308|
|1040792||Offshore sea floor pressure series||2006-08-09 17:52:30||42.59967 N, 60.62517 W||RRS Discovery D308|
|938450||Hydrography time series at depth||2007-10-08 00:30:01||42.59667 N, 60.63 W||CCGS Hudson HUD07045 Leg2|
|938462||Hydrography time series at depth||2007-10-08 00:30:01||42.59667 N, 60.63 W||CCGS Hudson HUD07045 Leg2|
|938542||Hydrography time series at depth||2007-10-08 00:30:01||42.59667 N, 60.63 W||CCGS Hudson HUD07045 Leg2|
|938498||Hydrography time series at depth||2007-10-08 01:00:01||42.59667 N, 60.63 W||CCGS Hudson HUD07045 Leg2|
|1040811||Offshore sea floor pressure series||2007-10-08 07:52:30||42.59615 N, 60.62918 W||CCGS Hudson HUD07045 Leg2|