Metadata Report for BODC Series Reference Number 808256
No Problem Report Found in the Database
Open Data supplied by Natural Environment Research Council (NERC)
You must always use the following attribution statement to acknowledge the source of the information: "Contains data supplied by Natural Environment Research Council."
Falmouth Scientific Inc. OEM CT sensor
The OEM CT sensor is designed to provide high accuracy conductivity and temperature measurements in a package that can be readily integrated into user systems. The CT sensor relies on an inductively coupled conductivity sensor, with a large inside diameter that eliminates the need for pumps. A high grade Platinum Resistance Thermometer is used to measure temperature.
Sensor specifications are given in the table below. Since 2009 this instrument has been manufactured by Teledyne RD Instruments as a Citadel CT-EK Sensor. More information about the instrument can be found on the Teledyne Citadel specification sheet.
|Instrument Parameter||Small CT Cell Conductivity||Large CT Cell Conductivity||Temperature|
|Range||0 to 70 mS cm-1||0 to 70 mS cm-1||-2 to 35 degrees C|
|Accuracy||±0.020 mS cm-1||±0.010 mS cm-1||±0.050 degrees C|
|Stability||±0.005 mS cm-1 mo-1||±0.003 mS cm-1||±0.005 degrees C mo-1|
|Response||20 cm @ 1 m s-1||15 cm @ 1 m s-1||20 seconds internal, 1 second external|
|Power Input||50 mW @ 6 VDC, voltage range 6 - 14 VDC|
|Logic||2 0 - 5 VDC control lines|
|Output Impedance||500 ohms|
Falmouth Scientific Inc. Ocean Sensor Modules
FSI's individual sensor modules include an Ocean Conductivity Module (OCM), Ocean Temperature Module (OTM) and Ocean Pressure Module (OPM). All three use a low power micro-controller to collect, scale and transmit real-time data via RS-232 or RS-485.
|Parameter||OCM Conductivity||OTM Temperature||OPM Pressure|
|Range||0 - 7.0 S/m(0 - 70 mS/cm)||-2 to 32 °C||User Specified:0-200 dBar0-1000 dBar0-2000 dBar0-3000 dBar0-7000 dBar|
|Accuracy||-0.0003* S/m(-0.003 mS/cm)||-0.003 °C*||-0.03% full scale*|
|Stability /month||-0.00005 S/m(-0.0005 mS/cm)||-0.0005 °C||-0.002% full scale|
|Resolution||0.00001 S/m(-0.0001 mS/cm)||0.0001 °C||0.0004% full scale|
|Response at 1 m/s flow||50 msec||150 msec||25 msec|
|Sensor Type||Inductive cell||Platinum thermometer||Strain gauge|
* Higher accuracy available
For further details, see the manufacturer's specification sheet.
RAPID Cruise CD170 Surface Hydrography Instrument Details
The surface meteorology and thermosalinograph measurements were made by the RSU/UKORS Surfmet system. The depth of the ship's intake is 2.5 m. The instruments used, together with their serial numbers and manufacturer are listed below.
|Sensor||Serial number||Last calibration date|
|FSI OCM housing conductivity sensor||1376||Calibration stored internally|
|FSI OTM housing temperature sensor||1340||25/06/2002|
|FSI OTM remote temperature sensor||1348||June 2003|
RAPID Cruise CD170 Sea Surface Hydrography, Meteorology and Navigation
|Dates||2 - 27 April 2005|
|Principal Scientific Officer||Dr Stuart Cunningham (SOC)|
The data series supplied by the originator covers 02/04/2005 to 22/04/2005, which is less than the duration of the cruise.
A full copy of the Metadata report can be found here: CD170
Data Aquisition and Onboard Processing
Onboard processing was carried out on a daily basis and involved running a sequence of executable programs. The initial stage transferred the underway surfmet data into PSTAR from RVS format. Subsequent processing included the calculation of salinity and the merging of the different data streams (heading, bestnav, gyro and ash-gyro). An additional executable was run to determine the true wind speed and direction, taking account of the ship's motion and velocity.
BODC Underway Data Processing Procedures
All sea surface hydrographic, navigation and meteorological data were transferred from Matlab format into BODC internal format (QXF). Reformatting and data calibration was carried out, and is discussed in the individual instrument sections. Each data channel was visually inspected and any spikes or periods of dubious data flagged as suspect using the BODC in house visualisation tool EDSERPLO. The capabilities of the workstation screening software allows all possible comparative screening checks between channels (e.g. to ensure corrected wind data have not been influenced by changes in ship's heading). The system also has the facility of simultaneously displaying the data and the ship's position on a map to enable data screening to take oceanographic climatology into account.
The qxf file then underwent a further step. This involved using Matlab to split the qxf file into three separarte qxf files. One contained data for hydrography, one for meterological data and the final qxf file held the navigation data.
RAPID Cruise CD170 Surface Hydrography Processing
The underway salinity channel was calibrated by the data originator using independent bottle salinity samples drawn from the ship's uncontaminated water supply at 4 hour intervals.
Calibration was achieved with a combination of PSTAR and Matlab routines. Bottle salinity data (.csv files) were transferred to the ship's Unix system and appended into one file. Salinities were converted back to conductivities and merged underway conductivity data using the time variable. The discrete bottle samples with matching salinities were used to compute a salinity difference that was filtered and added to the surface salinities.
Sea surface temperature has not been calibrated against another source. Attempts were made at BODC to use CTD temperature, averaged over the top 2.5 m as a source of verification. However, there were only three resulting points. The offset (CTD temperature minus underway sea surface temperature) was examined. One of the points had a large offset and the underway component had a large standard deviation associated with it; therefore it was discarded. The remaining two points (mean offset of -0.03, standard deviation 0.002) were not deemed sufficient to base a calibration upon.
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.
Monitoring the Meridional Overturning Circulation at 26.5N (RAPIDMOC)
There is a northward transport of heat throughout the Atlantic, reaching a maximum of 1.3PW (25% of the global heat flux) around 24.5°N. The heat transport is a balance of the northward flux of a warm Gulf Stream, and a southward flux of cooler thermocline and cold North Atlantic Deep Water that is known as the meridional overturning circulation (MOC). As a consequence of the MOC northwest Europe enjoys a mild climate for its latitude: however abrupt rearrangement of the Atlantic Circulation has been shown in climate models and in palaeoclimate records to be responsible for a cooling of European climate of between 5-10°C. A principal objective of the RAPID programme is the development of a pre-operational prototype system that will continuously observe the strength and structure of the MOC. An initiative has been formed to fulfill this objective and consists of three interlinked projects:
- A mooring array spanning the Atlantic at 26.5°N to measure the southward branch of the MOC (Hirschi et al., 2003 and Baehr et al., 2004).
- Additional moorings deployed in the western boundary along 26.5°N (by Prof. Bill Johns, University of Miami) to resolve transport in the Deep Western Boundary Current (Bryden et al., 2005). These moorings allow surface-to-bottom density profiles along the western boundary, Mid-Atlantic Ridge, and eastern boundary to be observed. As a result, the transatlantic pressure gradient can be continuously measured.
- Monitoring of the northward branch of the MOC using submarine telephone cables in the Florida Straits (Baringer et al., 2001) led by Dr Molly Baringer (NOAA/AOML/PHOD).
The entire monitoring array system created by the three projects will be recovered and redeployed annually until 2008 under RAPID funding. From 2008 until 2014 the array will continue to be serviced annually under RAPID-WATCH funding.
The array will be focussed on three regions, the Eastern Boundary (EB), the Mid Atlantic Ridge (MAR) and the Western Boundary (WB). The geographical extent of these regions are as follows:
- Eastern Boundary (EB) array defined as a box with the south-east corner at 23.5°N, 25.5°W and the north-west corner at 29.0°N, 12.0°W
- Mid Atlantic Ridge (MAR) array defined as a box with the south-east corner at 23.0°N, 52.1°W and the north-west corner at 26.5°N, 40.0°W
- Western Boundary (WB) array defined as a box with the south-east corner at 26.0°N, 77.5°W and the north-west corner at 27.5°N, 69.5°W
Baehr, J., Hirschi, J., Beismann, J.O. and Marotzke, J. (2004) Monitoring the meridional overturning circulation in the North Atlantic: A model-based array design study. Journal of Marine Research, Volume 62, No 3, pp 283-312.
Baringer, M.O'N. and Larsen, J.C. (2001) Sixteen years of Florida Current transport at 27N Geophysical Research Letters, Volume 28, No 16, pp3179-3182
Bryden, H.L., Johns, W.E. and Saunders, P.M. (2005) Deep Western Boundary Current East of Abaco: Mean structure and transport. Journal of Marine Research, Volume 63, No 1, pp 35-57.
Hirschi, J., Baehr, J., Marotzke J., Stark J., Cunningham S.A. and Beismann J.O. (2003) A monitoring design for the Atlantic meridional overturning circulation. Geophysical Research Letters, Volume 30, No 7, article number 1413 (DOI 10.1029/2002GL016776)
|Principal Scientist(s)||Stuart A Cunningham (Southampton Oceanography Centre)|
|Ship||RRS Charles Darwin|
Complete Cruise Metadata Report is available here
No Fixed Station Information held for the Series
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|