Metadata Report for BODC Series Reference Number 686749
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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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
Nortek Aquadopp Open Water Current Meter
This instrument provides 3D acoustic doppler current measurements along with standard measurements of temperature, pressure, tilt and direction. It can be used in real time measurement situations or can log to an internal recorder powered by internal batteries. It can also be configured to measure surface wave height, period and direction concurrently. It has the unique feature of being run in 'diagnostic' mode when set to collect data at 1 Hz frequency in user specified intervals. This allows studies of mooring motion and the performance of other current meters to be conducted. It can be set in various configurations with titanium housings for deployment at greater depths.
Standard Measured Parameters
- 3D current velocity (East/North/Up, X/Y/Z or Beam 1/2/3)
- Acoustic signal strength (Beam 1/2/3)
- Compass
- Tilt
- Temperature
- Pressure
- Battery voltage
- Status code
- Error code
Surface wave monitoring
The standard Aquadopp is suitable for measuring surface wave height, period, and direction, which are calculated using the PUV method whereby spectra are estimated based on a combination of the pressure signal recorded by the instrument (P) and two horizontal components of the wave orbital velocity (U and V). More specifically, the pressure signal is used to provide an estimate of the wave frequency spectrum. The energy in this spectrum is then used to estimate wave height and period. The measurements of the wave orbital velocities are used to provide an estimate of the wave direction. Since these estimates are based on the distribution of wave energy and are not direct measurements of the free surface, they should be considered inferred estimates.
Both the dynamic pressure and the orbital velocities are driven by surface waves. The signals that are associated with these properties are complicated by the fact that they attenuate (that is the signals are weaker) with depth. The exact behaviour of the attenuation is determined by the water depth and the wavelength being observed. The greater the water depth the greater the attenuation; likewise, the shorter the wavelength (or higher the frequency of the wave) the greater the attenuation for a given water depth. This means that the estimation of wave parameters is limited by both water depth and wave frequency.
Specifications
| Water Velocity Measurement | |
|---|---|
| Range | ± 5 m/s (standard 300 m version) ± 3 m/s (3000 m and 6000 m versions - higher ranges available on request) |
| Accuracy | 1% of measured value ± 0.5 cm/s |
| Max. sampling rate | 1 Hz, 4 Hz also available on request (standard version) |
| Internal sampling rate | 23 Hz |
| Measurement Area | |
| Measurement cell size | 0.75 m |
| Measurement cell position | 0.35 - 5.0 m |
| Default position | 0.35 - 1.8 m |
| Doppler uncertainty (noise) | |
| Typical | 0.5 - 1.0 cm/s |
| At 1 Hz sampling rate | 1.5 cm/s |
| Echo Intensity | |
| Acoustic frequency | 2 MHz |
| Resolution | 0.45 dB |
| Dynamic range | 90 dB |
| Sensors | |
| Temperature | Thermistor embedded in head |
| Range | -4°C to 40°C |
| Accuracy/resolution | 0.1°C / 0.01°C |
| Time response | 10 min |
| Compass | Magnetometer |
| Accuracy/Resolution | 2° / 0.1° for tilt < 20° |
| Tilt | Liquid level |
| Maximum tilt | 30° |
| Up or down | Automatic detect |
| Pressure | Piezoresistive |
| Range | 0 - 300 m (standard), 0 - 3000 m or 0 - 6000 m |
| Accuracy/resolution | 0.5% |
| Analogue Inputs | |
| No. of channels | 2 |
| Voltage supply | 12 V |
| Voltage input | 16 bit A/D |
| Materials | |
| Standard version | Delrin with titanium screws |
| 3000 m version | Delrin with titanium screws |
| 6000 m version | Titanium with Delrin transducer head |
| Environmental | |
| Operating temperature | -4°C to 40°C |
| Dimensions | |
| Cylinder | 568 mm x 75 mm (standard) 619 mm x 84 mm (3000 m version) 625 mm x 84 mm (6000 m version) |
| Weight in air | 3.5 kg (standard) 3.6 kg (3000 m version) 7.6 kg (6000 m version) |
| Weight in water | Neutral (standard) 1.2 kg (3000 m version) 4.8 kg (6000 m version) |
Further details can be found in the manufacturer's specification sheets for the Aquadopp, Aquadopp 3000 and Aquadopp 6000.
RAPIDMOC/MOCHA Current Meter data processing document
This document outlines the procedures undertaken to process and quality assure current meter data collected under the RAPIDMOC and MOCHA projects.
Originator's processing
The raw data are downloaded from the instrument and converted to ASCII format.
Once in ASCII format the data are corrected for the following -
- Speed bias (caused by the mooring motion)
- Sound speed (as electromagnetic current meter sensors use the speed of sound in water to calculate the doppler shift in the returned signal, they are corrected for variations in sound speed using temperature data as sound speed varies with temperature).
- Magnetic variation
A 40 hour low pass filter is also applied to the data.
Calculating and applying calibrations
Manufacturers calibrations are applied.
Quality Control
Data were visually inspected for out-lying data and instrument electrical spikes removed.
BODC processing
Data are received after quality checks have been made and calibrations have been applied. The data files are submitted in ASCII format as one file per instrument.
Once the submitted data files are safely archived, the data undergo reformatting and banking procedures:
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The data files are transferred into a common format, a NetCDF subset.
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Standard parameter codes are assigned 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:
| Identifier | Unit | Definition | BODC parameter code | Units | Unit conversion | Comments |
|---|---|---|---|---|---|---|
| YY | year | Year | AADYAA01 | days | - | Combined with MM and DD to form a date and transferred |
| MM | month | Month | AADYAA01 | days | - | Combined with MM and DD to form a date and transferred |
| DD | day | Day | AADYAA01 | days | - | Combined with MM and DD to form a date and transferred |
| HH | hour | Decimal hours | AAFDZZ01 | days | /24 | Transferred |
| T | °C | Temperature | TEMPPR01 | °C | - | Transferred |
| P | dbar | Pressure | PRSTPR01 | dbar | - | Transferred |
| U | cm/s | Eastward velocity | LCEWEL01 | cm/s | - | Transferred |
| V | cm/s | Northward velocity | LCNSEL01 | cm/s | - | Transferred |
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)
Meridional Overturning Circulation and Heatflux Array (MOCHA) Project
Introduction
Users of these data are referred to the Meridional Overturning Circulation and Heatflux Array (MOCHA) Project Website for more information. The following text has been taken from the website.
Scientific Rationale
To set in place a system for continuous observation of the meridional heat transport in the subtropical Atlantic, with which to document its variability and its relationship to oberved climate fluctuations, and to assess climate model predictions
Overview
MOCHA is a collaborative project, partnered with the UK RAPID Program, to measure the heat and freshwater transports of the North Atlantic Ocean. These transports are called the Thermohaline or Overturning Circulation. Simply put, warm waters move poleward at the surface of the ocean, where they cool and sink, to return equatorward in the deep ocean.
Data Activity or Cruise Information
Data Activity
| Start Date (yyyy-mm-dd) | 2004-03-24 |
| End Date (yyyy-mm-dd) | 2005-05-11 |
| Organization Undertaking Activity | Rosenstiel School of Marine and Atmospheric Science |
| Country of Organization | United States |
| Originator's Data Activity Identifier | WB3#1 |
| Platform Category | subsurface mooring |
RAPID Moored Instrument Rig WB3#1
This rig was deployed as part of the Western Boundary (WB) array of the MOCHA/RAPIDMOC project.
| Deployment cruise | RRS Discovery cruise D278 |
|---|---|
| Recovery cruise | RV Knorr cruise KN182_2 |
The rig was anchored by railway wheels and kept erect by 17" diameter glass subsurface buoyancy spheres located at intervals along the mooring.
Instruments deployed on the rig
| Depth | Instrument |
|---|---|
| 50m | Sea-Bird SBE37 MicroCAT (#0481) |
| 100m | Sea-Bird SBE37 MicroCAT (#0487) |
| 100m | SonTek Argonaut MD current meter (#276) |
| 250m | Sea-Bird SBE37 MicroCAT (#0483) |
| 400m | Sea-Bird SBE37 MicroCAT (#3166) |
| 400m | Nortek Aquadopp current meter (#1136) |
| 410m | SonTek Argonaut MD current meter |
| 600m | Sea-Bird SBE37 MicroCAT (#0486) |
| 800m | Sea-Bird SBE37 MicroCAT (#3165) |
| 800m | Nortek Aquadopp current meter (#1144) |
| 1000m | Sea-Bird SBE37 MicroCAT (#0482) |
| 1200m | Sea-Bird SBE37 MicroCAT (#3167) |
| 1200m | Nortek Aquadopp current meter (#1123) |
| 1600m | Sea-Bird SBE37 MicroCAT (#484) |
| 2000m | Sea-Bird SBE37 MicroCAT (#3164) |
| 2000m | Nortek Aquadopp current meter (#1148) |
| 2500m | Sea-Bird SBE37 MicroCAT (#485) |
| 3000m | Sea-Bird SBE37 MicroCAT (#3168) |
| 3000m | Nortek Aquadopp current meter (#1156) |
| 3500m | Sea-Bird SBE16 SEACAT (#1655) |
| 4000m | Sea-Bird SBE37 MicroCAT (#3163) |
| 4000m | Nortek Aquadopp current meter (#1138) |
| 4010m | SonTek Argonaut MD current meter |
| 4500m | Sea-Bird SBE16 SEACAT (#1659) |
| 4840m | Sea-Bird SBE16 SEACAT (#0999) |
The SBE16 SEACAT #0999 was fitted with a Digiquartz pressure sensor.
The SonTek Argonaut MD current meters at 410 m and 4010 m are for comparison purposes only (with the Nortek Aquadopp current meters) and will not be part of the 'official' instruments on this mooring. Therefore the data will not be provided. SBE16 SEACAT's #1655 and #1659 failed, therefore no data are available from these instruments.
Other Series linked to this Data Activity - 686725 701975 709744 686701 686737 702026 702063 686750 701963 702002 702087 701987 702014 686713 702051 686762 702038 701951 701999 702075
Cruise
| Cruise Name | D278 |
| Departure Date | 2004-03-19 |
| Arrival Date | 2004-03-30 |
| Principal Scientist(s) | Stuart A Cunningham (Southampton Oceanography Centre) |
| Ship | RRS Discovery |
Complete Cruise Metadata Report is available here
Fixed Station Information
Fixed Station Information
| Station Name | Western Boundary Array |
| Category | Offshore area |
| Latitude | 26° 37.50' N |
| Longitude | 73° 37.50' W |
| Water depth below MSL |
RAPIDMOC Western Boundary (WB) Array
The Western Boundary Array defines a box in which moorings were deployed at the western side of the North Atlantic as part of the RAPIDMOC project and the collaborative project Meridional Overturning Circulation and Heatflux Array (MOCHA). The box region has latitudinal limits of 26° N to 27.5° N and longitudinal limits of 69.5° W to 77.5° W. Moorings have occupied this region since 2004 and are typically deployed for 6 to 18 months.
Moored data summary
| Year | Cruise ID | Number of moorings | Data types (number of instruments) |
|---|---|---|---|
| 2004 | D278 | 9 (6 RAPIDMOC, 3 MOCHA) | ADCP (2), BPR (8), CM (29), MCTD (52), MMP (1) |
| 2005 | KN182_2 | 11 (6 RAPIDMOC, 5 MOCHA) | ADCP (2), BPR (6), CM (27), MCTD (56) |
| 2006 | RB06-02, SJ14-06 | 11 (6 RAPIDMOC, 5 MOCHA) | ADCP (1), BPR (3), CM (22), IES (7), MCTD (60) |
| 2007 | RB07-01 | 7 (7 RAPIDMOC) | ADCP (1), BPR (4), CM (16), MCTD (47) |
| 2008 | SJ08-03 | 11 (8 RAPIDMOC, 3 MOCHA) | ADCP (2), BPR (3), CM (40), MCTD (80) |
| 2009 | RB0901, D344, D345 | 16 (11 RAPIDMOC, 5 MOCHA) | ADCP (2), BPR (5), CM (39), MCTD (91), DVS (1) |
| 2010 | OC459-1, RB1009 | 9 (8 RAPIDMOC, 1 MOCHA) | ADCP (1), BPR (7), CM (23), MCTD (54) |
| 2011 | KN200-4 | 7 (7 RAPIDMOC, 6 MOCHA) | ADCP (2), BPR (7), CM (43), MCTD (86), DVS (1), IES (1) |
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 | DIS, MET, NAV, SADCP, SURF | 1 |
| D278 | Initial array deployment | DIS, MET, NAV, SADCP, SURF | 16 |
| D279 | Hydrographic section | CTD, DIS, LADCP, MET, NAV, SADCP, SURF | 31 |
| KN182_2 | Array service | CTD, DIS, MET, NAV, SADCP, SURF | 64 |
| RB0601 | Array service | CTD, DIS, LADCP, MET, NAV, SADCP, SURF | 39 |
| SJ14-06 | Array service | CTD, DIS, LADCP, MET, NAV, SADCP, SURF | 33 |
| RB07-01 | Array service | CTD, DIS, LADCP, MET, NAV, SADCP, SURF | 36 |
| SJ08-03 | Array service | CTD, DIS, LADCP, MET, NAV, SADCP, SURF | 33 |
| RB0901 | Array service | CTD, DIS, LADCP, MET, NAV, SADCP, SURF | 35 |
| D344 | Array service | CTD, DIS, MET, NAV, SADCP, SURF | 3 |
| D345 | Array service | CTD, DIS, LADCP, MET, NAV, SADCP, SURF | 24 |
| OC459-1 | Array service | CTD, DIS, MET, NAV, SADCP, SURF | 9 |
| OC459-2 | Western Boundary Hydrographic section | CTD, DIS, LADCP, MET, NAV, SADCP, SURF | 27 |
| D346 | Hydrographic section | CTD, DIS, LADCP, MET, NAV, SADCP, SURF | 31 |
| RB1009 | WB4 service | CTD, MET, SURF, NAV | 2 |
| KN200-4 | Array service | CTD, DIS, MET, NAV, SURF | 34 |
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 |
| DVS | Doppler Volume sampler |
| 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 - 686670 686682 686694 686701 686713 686725 686737 686750 686762 686774 686786 686798 686805 686817 686829 686830 686842 686854 686866 686878 686891 686909 686910 686934 686946 686958 687022 696560 696572 701951 701963 701975 701987 701999 702002 702014 702026 702038 702051 702063 702075 702087 702099 702106 702118 702131 702143 702155 702167 702179 702180 702192 702211 702223 702235 702247 703681 703693 703700 703712 703724 703736 703748 703761 703773 703785 703797 703804 703816 703828 703841 703853 703865 703877 703889 703890 703908 703921 703933 703945 703957 709744 709756 732808 732821 732833 732845 732857 734747
Other Cruises linked to this Fixed Station (with the number of series) - D278 (89) D344 (8) D345 (41) D346 (31) KN182_2 (85) KN200-4 (86) OC459-1 (56) RB0602 (42) RB0701 (58) RB0901 (75) RB1009 (24) RB1201 (55) SJ-08-03 Leg 1 (37) SJ-08-03 Leg 2 (75) SJ-14-06 (62)
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 |
