Metadata Report for BODC Series Reference Number 946161
Metadata Summary
Problem Reports
Data Access Policy
Narrative Documents
Project Information
Data Activity or Cruise Information
Fixed Station Information
BODC Quality Flags
Metadata Summary
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Time Co-ordinates(UT) |
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Parameters |
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Problem Reports
No Problem Report Found in the Database
RAPIDMOC Data Quality Report
The pressure and pressure residual data are of good quality.
The temperature data in all series have step-like features. This is thought to be due to the magnitude of the changes in temperature being approximately equal to the resolution of the instrument. Therefore, the temperature data should be used with caution.
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
Sea-Bird SBE-26 SEAGAUGE Wave and Tide Recorder
The SEAGAUGE SBE 26 is a wave & tide recorder manufactured by Sea-Bird Electronics (www.seabird.com) which integrates water level measurements and characterizes waves with interleaved bursts of sampling at up to 4 Hz. The SBE 26 combines a Digiquartz pressure sensor, accurate clock, precision thermometer and optional conductivity sensor.
The SEAGAUGE SBE 26 continuously integrates pressure samples to obtain water level measurements unaffected by wave action, and also independently burst-samples pressure at rates up to 4 Hz for wave amplitude calculation. Water level integration and wave burst sampling intervals are programmable. The large memory permits frequent water level recording and detailed wave characterization.
Specifications
Pressure
| Measurement range | 0 to 21 m |
|---|---|
| Accuracy | 0.01% FS (3 mm) |
| Repeatability | 0.005% (1.5 mm) |
| Hysteresis | 0.005% (1.5 mm) |
| Tide resolution | 0.2 mm with 1 mn integration 0.01 mm with 15 mn integration |
| Wave resolution | 0.4 mm with 0.26 sec integration 0.1 mm with 1 sec integration |
| Calibration | 0 psia to full scale pressure (45 psia) |
Temperature [°C]
| Measurement range | -5 to +35 |
|---|---|
| Accuracy | 0.02 |
| Resolution | 0.01 |
| Calibration | -1 to +31 |
Sea-Bird software processing
Default data processing is carried out using the manufacturer's software package ('SEASOFT for Waves') which performs auto-spectrum and time-series analyses and provides facilities for deployment planning, instrument set- up, data retrieval and plotting.
RAPIDMOC Calibration Coefficients: Series 946161
| BODC Series identifier | 946161 |
|---|---|
| Instrument Serial number | 0390 |
| Deployment cruise | D324 |
| Recovery cruise | D344 |
Processing Log
purge_bp.m: Pressure offset of 11.79 dbar NOT removed
purge_bp.m: 0 spikes removed
Exponential-linear pressure fit to be stored with data:
amplitude of exponential decay: -0.087629 db
time-constant of exponential decay: 38.623091 days
linear slope: 0.000043 db/day
mean offset: 5198.201136 db
RAPIDMOC Sea-Bird SEAGAUGE data processing document
This document outlines the procedures undertaken to process and quality assure the SEAGAUGE data collected under the RAPIDMOC project.
Originator's processing
The raw data are downloaded from the instrument and converted to ASCII format. All processing is performed in Matlab.
Processing
Processing steps which are undertaken include
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calculation and removal of a post recovery clock offset.
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calculation of a pressure offset for atmospheric correction. However, this may not be applied. See the calibration coefficients documents for each series for more information.
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calculation of an exponential-linear or pure linear pressure fit. This is stored with pressure and temperature data in a file with a .use extension.
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filtering of the pressure data using a 2 day low pass filter to remove the diurnal and semi-diurnal tides.
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interpolating the temperature and de-trended, filtered pressure data onto a 12 hour time grid. This is stored in a file with a .seagauge extension.
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calculation of a harmonic fit of the fortnightly and monthly tides. Also stored in the .seagauge extension file.
Quality control
All variables in specified time intervals can be set to dummy values if the data are suspicious. Any data deemed as suspicious, i.e. a spike, are removed.
BODC processing
Data are received after quality checks have been made and calibrations have been applied by the originator. The data files are submitted in ASCII format as two files per instrument.
Once the submitted data files are safely archived, the data undergo reformatting and banking procedures:
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The data are transferred into a common format, a NetCDF subset.
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The pressure and temperature channels from the .use file are combined with the pressure residual channel (de-trended and 2-day low pass filtered) from the .seagauge file into a single file. In addition a de-trended, unfiltered pressure (measured variable) series is derived by subtracting the calculated trend from the observed pressure, which were supplied in the originator's files with an extension of .use.
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Standard parameter codes are assigned to each channel that accurately describe the data (see Parameter mapping section below).
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Unit conversions are applied, if necessary, so that units are standardised (see Parameter mapping section below).
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The data are screened visually and any spikes or instrument malfunctions can be clearly labelled with quality control flags.
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Comprehensive documentation is prepared describing the collection, processing and quality of each data series.
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Detailed metadata and documents are loaded to the database and linked to each series so that the information is readily available to future users.
Parameter mapping
The following describes the parameters contained in the originator's files and their mapping to BODC parameter codes :
| File extension | Identifier | Unit | Definition | BODC parameter code | Units | Unit conversion | Comments |
|---|---|---|---|---|---|---|---|
| use | YY | year | Year | AADYAA01 | days | - | Combined with MM and DD to form a date and transferred |
| use | MM | month | Month | AADYAA01 | days | - | Combined with MM and DD to form a date and transferred |
| use | DD | day | Day | AADYAA01 | days | - | Combined with MM and DD to form a date and transferred |
| use | HH | hour | Decimal hours | AAFDZZ01 | days | /24 | Transferred |
| use | P | decibars | Pressure | PRSTPS01 | decibars | - | Transferred |
| use | T | °C | Temperature (IPTS-90) | TEMPPR01 | °C | - | Transferred |
| use | PFIT | decibars | Exponential-linear or pure linear trend of pressure (decibars). | - | - | - | See parameter derivation table below |
| seagauge | YY | year | Year | AADYAA01 | days | - | Combined with MM and DD to form a date and transferred |
| seagauge | MM | month | Month | AADYAA01 | days | - | Combined with MM and DD to form a date and transferred |
| seagauge | DD | day | Day | AADYAA01 | days | - | Combined with MM and DD to form a date and transferred |
| seagauge | HH | hour | Decimal hours | AAFDZZ01 | days | /24 | Transferred |
| seagauge | P | decibars | Pressure residual after drift removal and 2-day low pass filtering i.e. tides removed | PRSTRS01 | decibars | - | 12 hour resolution, transferred |
| seagauge | T | °C | Temperature (IPTS-90) | - | - | - | Not transferred as use file contains higher resolution |
| seagauge | PFIT | decibars | Harmonic fit of the fortnightly and monthly tides (decibars) | - | - | - | Not transferred as only a tidal prediction |
Parameter derivation
The following describes the parameters derived by BODC and their mapping to BODC parameter codes:
| BODC parameter code | Units | File extension | Identifier | Definition | Units | Equation | Comments |
|---|---|---|---|---|---|---|---|
| PRSTDR01 | decibars | use use | P PFIT | Pressure Exponential-linear or pure linear trend of pressure. | decibars decibars | P-PFIT | pressure series that is de-trended and unfiltered i.e. still contains tides |
Project Information
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.
Scientific Objectives
- 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.
Projects
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)
Scientific Rationale
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
References
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)
Data Activity or Cruise Information
Data Activity
| Start Date (yyyy-mm-dd) | 2007-11-03 |
| End Date (yyyy-mm-dd) | 2009-10-29 |
| Organization Undertaking Activity | National Oceanography Centre, Southampton |
| Country of Organization | United Kingdom |
| Originator's Data Activity Identifier | EB1L4_4 |
| Platform Category | fixed benthic node |
RAPID Moored Instrument Rig EB1L4_4
This rig was deployed as part of the Eastern Boundary (EB) array of the RAPIDMOC project.
| Deployment cruise | RRS Discovery cruise D324 |
|---|---|
| Recovery cruise | RRS Discovery cruise D344 |
The rig was anchored by a 280 kg anchor and kept erect by sub-surface floats attached along the mooring. The instruments were attached to a tripod assembly.
Instruments deployed on the rig
| Depth | Instrument |
|---|---|
| 5103 m | Sea-Bird SBE26 SEAGAUGE Wave and Tide Recorder (#0390) |
| 5103 m | Sea-Bird SBE26 SEAGAUGE Wave and Tide Recorder (#0391) |
Other Series linked to this Data Activity - 946173
Cruise
| Cruise Name | D324 |
| Departure Date | 2007-10-06 |
| Arrival Date | 2007-11-09 |
| Principal Scientist(s) | Stuart A Cunningham (National Oceanography Centre, Southampton) |
| Ship | RRS Discovery |
Complete Cruise Metadata Report is available here
Fixed Station Information
Fixed Station Information
| Station Name | Eastern Boundary Array |
| Category | Offshore area |
| Latitude | 25° 51.60' N |
| Longitude | 18° 43.98' W |
| Water depth below MSL |
RAPIDMOC Eastern Boundary (EB) Array
The Eastern Boundary Array defines a box in which moorings are deployed at the eastern side of the North Atlantic as part of the RAPIDMOC project. The box region has latitudinal limits of 23.5° N to 29° N and longitudinal limits of 12° W to 25.5° W. Moorings have occupied this region since 2004 and are typically deployed for 6 to 18 months.
Moored data summary
A description of the data types can be found at the bottom of this document.
| Year | Cruise ID | Number of moorings | Data types (number of instruments) |
|---|---|---|---|
| 2004 | D277, PO319 | 11 | BPR (7), CM (10), MCTD (32) |
| 2005 | CD170,CD177 | 15 | ADCP (1), BPR (4), CM (4), MCTD (71), IES (2), MMP (1) |
| 2006 | D304, PO343, PO345 | 24 | BPR (6), CM (4), MCTD (78), MMP (1) |
| 2007 | D324 | 13 | BPR (3), MCTD (53), IES (2) |
| 2008 | D334 | 14 | BPR (3), CM (2), MCTD (44), IES (1) |
| 2009 | D344 | 14 | BPR (4), CM (2), MCTD (44) |
| 2011 | D359, JC064 | 22 | BPR (12), CM (18), MCTD (80), IES (1) |
| 2012 | D382 | 9 | BPR (6), CM (10), MCTD (50) |
Cruise data summary
During the cruises to service the moored array, a variety of data types are collected. The table below is a summary of these data. The number of CTD profiles performed on these cruises within the box region defined above is also included. Trans-Atlantic hydrographic CTD sections have also been performed since 2004 and are included in the table.
| Cruise ID | Cruise description | Data types | Number of CTD profiles performed within the box region |
|---|---|---|---|
| D277 | Initial array deployment | MET, NAV, SADCP, SURF | - |
| D279 | Hydrographic section | CTD, DIS, LADCP, MET, NAV, SADCP, SURF | 21 |
| CD170 | Array service | BATH, CTD, DIS, MET, NAV, SADCP, SURF | 4 |
| CD177 | Array service | BATH, CTD, DIS, MET, NAV, SADCP, SURF | 6 |
| D304 | Array service | CTD, DIS, MET, NAV, SADCP, SURF | 8 |
| PO343 | Array service | CTD, DIS, MET, NAV, SADCP, SURF | 5 |
| PO345 | Array service | CTD, DIS, MET, NAV, SADCP, SURF | 4 |
| D324 | Array service | CTD, DIS, MET, NAV, SADCP, SURF | 5 |
| D334 | Array service | CTD, DIS, MET, NAV, SADCP, SURF | 15 |
| D344 | Array service | CTD, DIS, MET, NAV, SADCP, SURF | 5 |
| D346 | Hydrographic section | CTD, DIS, LADCP, MET, NAV, SADCP, SURF | 22 |
| D359 | Array service | CTD, DIS, MET, NAV, SADCP, SURF | 4 |
| JC064 | Array service | CTD, DIS, MET, NAV, SADCP, SURF | 5 |
| D382 | Array service | CTD, DIS, MET, NAV, SADCP, SURF | 5 |
Data type ID and description
| Data type ID | Description |
|---|---|
| ADCP | Acoustic Doppler Current Profiler |
| BATH | Bathymetry |
| BPR | Bottom Pressure Recorder |
| CM | Current Meter |
| CTD | Conductivity-Temperature-Depth profiler |
| DIS | Discrete water bottle samples |
| IES | Inverted Echo Sounder |
| LADCP | Lowered Acoustic Doppler Current Profiler |
| MET | Meteorology |
| MCTD | Moored Conductivity-Temperature-Depth sensor |
| MMP | McLane Moored Profiler - profiling CTD and current meter |
| NAV | Navigation |
| SADCP | Shipborne Acoustic Doppler Current Profiler |
| SURF | Sea surface data |
Other Series linked to this Fixed Station for this cruise - 768756 768768 768781 768836 768848 863206 863218 863231 863243 863255 863267 863279 863280 863292 863311 863323 863335 863347 863359 863360 863372 863384 863396 863403 863415 863427 863439 863440 863452 863464 863476 863488 863507 863519 863520 863532 863544 863556 863568 863581 863593 863600 863612 863624 863636 863648 863661 863673 863685 863697 863704 863716 863728 863741 863753 863765 864117 864129 946173 946197
Other Cruises linked to this Fixed Station (with the number of series) - CD170 (52) CD177 (31) D277 (39) D304 (57) D324 (60) D334 (42) D344 (45) D346 (22) D359 (44) JC064 (46) PO343 (10) PO345 (30)
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 |
