Metadata Report for BODC Series Reference Number 580126
No Problem Report Found in the Database
Open Data supplied by Natural Environment Research Council (NERC)
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Aanderaa Recording Current Meter Model 4/5
Manufacturer's specifications: Meter (recording unit: height 51cm, diameter 12.8cm, vane size 37x100cm; overall: length 137cm, height 75cm) is designed for depths down to 2000m (6000m RCM model 5). It incorporates a spindle which is shackled into the mooring line. The meter is attached to the spindle through a gimbal mounting which permits a maximum 27° deviation of the spindle from the vertical, the meter still remaining horizontal.
Meter comprises :-
Savonius rotor magnetically coupled to an electronic counter - the number of revolutions during the sampling interval giving the average current speed over the interval - starting speed 2cm/s (users find 1.5 to 3cm/s), range 2.5 to 250cm/s, accuracy greater of 1cm/s or 2 per cent.
Vane, which aligns instrument with current flow, has a balance weight ensuring static balance and tail fins to ensure dynamic balance in flows up to 250cm/s.
Magnetic compass (needle is clamped to potentiometer ring at instant of sampling only) - direction recorded with 0.35° resolution, 5° accuracy (1.5° claimed by MAFF, Lowestoft) for speeds 5 to 100cm/s, 7.5° accuracy for remaining speeds within 2.5 to 200cm/s range, maximum compass tilt (i.e. maximum deviation of the meter from the horizontal at which the meter still registers correctly) is 12° in both pitch and roll axes.
Quartz clock, accuracy better than 2sec/day within temperature range 0 to 20°C.
Thermistor (temperature sensor), standard range -2.46 to 21.48°C (max on high range 36.04°C), accuracy 0.15°C, resolution 0.1 per cent of range, 63 per cent response time 12sec.
Inductive cell conductivity sensor (optional), range 0 to 70mmho/cm standard resolution 0.1 per cent of range.
Bourdon tube pressure sensor (optional) driving a potentiometer - range 0 to 100, 200, 500, 1000 or (RCM4 to 3000psi), (RCM5 to 5000, or 8000psi), lowest calibrated pressure 14.24psi, accuracy 1 per cent of range, resolution 0.1 per cent of range.
Self balancing potentiometer which converts the output from each sensor into a 10 bit binary number for storage on magnetic tape.
Sample duration equals nominal interval between data cycles pre-chosen as 0.5, 1, 2, 5, 10, 15, 20, 30, 60 or 180 minutes. Sample recording order: meter reference number, temperature, (conductivity, pressure if installed), current direction, speed.
Manufacturer's calibration formulae:
Meters (manufactured prior to October 1974) with analogue measurement of speed, i.e. the Savonius rotor drives a potentiometer via a magnetically coupled follower and gearbox (6000 : 1 gear ratio):
speed = 1.5 + 246 * (M/T) cm/s (1)
meters with digital measurement of speed i.e. utilizing an electronic reed switch to count the total number of rotor revolutions during the sampling interval:
speed = 1.5 + 42 * B * (M/T) cm/s (2)
direction = 1.5 + 0.349N ° magnetic (3)
B is the number of rotor revolutions per count, M (bits) binary is the count over the sampling interval T (sec) and N (bits) binary is the direction reading.
Data collecting laboratories may calibrate their own meters and so not use the manufacturer's calibration equations.
Aanderaa Current Meter Data Processing
Data Originator's Processing
The following procedures are carried out before the data were supplied to BODC.
Data were downloaded from the instrument logger, and factory calibrations were applied to the current speed channel, and the pressure, conductivity and temperature channels when fitted. Where available, laboratory calibrations of the current direction channels were used; factory formulae were used in their absence. Where no form factor was known for the conductivity sensor, a value of 2.8 was used.
Please note (concerns vector averaged current data): The current data are averaged by the logger over the sampling interval, whereas the pressure, temperature and conductivity data are single point measurements taken at the end of the interval. The data originator has moved the time stamps to the mid-point of the vector averaging sampling interval for all channels without interpolation.
BODC Data Processing and Quality Control
Where pressure sensors were fitted: the data record was compared with the pressure computed from the water depth on deployment and rig geometry. The time series was visually screened for evidence of rig movement (e.g. trawling) and excessive leaning (perhaps due to strong currents).
Where temperature sensors were fitted: the data record was compared with calibrated CTD data taken in the vicinity and checked for agreement within a few tenths of a degree Celsius. Obvious spikes were flagged. Periods of excessively noisy data were noted.
Where conductivity sensors were fitted: salinity (PSS-78) was computed from in-situ temperature and conductivity and a nominal pressure computed from the water depth on deployment and rig geometry. Obvious spikes were flagged.
General Data Screening carried out by BODC
BODC screen both the series header qualifying information and the parameter values in the data cycles themselves.
Header information is inspected for:
- Irregularities such as unfeasible values
- Inconsistencies between related information, for example:
- Times for instrument deployment and for start/end of data series
- Length of record and the number of data cycles/cycle interval
- Parameters expected and the parameters actually present in the data cycles
- Originator's comments on meter/mooring performance and data quality
Documents are written by BODC highlighting irregularities which cannot be resolved.
Data cycles are inspected using time or depth series plots of all parameters. Currents are additionally inspected using vector scatter plots and time series plots of North and East velocity components. These presentations undergo intrinsic and extrinsic screening to detect infeasible values within the data cycles themselves and inconsistencies as seen when comparing characteristics of adjacent data sets displaced with respect to depth, position or time. Values suspected of being of non-oceanographic origin may be tagged with the BODC flag denoting suspect value; the data values will not be altered.
The following types of irregularity, each relying on visual detection in the plot, are amongst those which may be flagged as suspect:
- Spurious data at the start or end of the record.
- Obvious spikes occurring in periods free from meteorological disturbance.
- A sequence of constant values in consecutive data cycles.
If a large percentage of the data is affected by irregularities then a Problem Report will be written rather than flagging the individual suspect values. Problem Reports are also used to highlight irregularities seen in the graphical data presentations.
Inconsistencies between the characteristics of the data set and those of its neighbours are sought and, where necessary, documented. This covers inconsistencies such as the following:
- Maximum and minimum values of parameters (spikes excluded).
- The occurrence of meteorological events.
This intrinsic and extrinsic screening of the parameter values seeks to confirm the qualifying information and the source laboratory's comments on the series. In screening and collating information, every care is taken to ensure that errors of BODC making are not introduced.
North Sea Project
The North Sea Project (NSP) was the first Marine Sciences Community Research project of the Natural Environment Research Council (NERC). It evolved from a NERC review of shelf sea research, which identified the need for a concerted multidisciplinary study of circulation, transport and production.
The ultimate aim of the NERC North Sea Project was the development of a suite of prognostic water quality models to aid management of the North Sea. To progress towards water quality models, three intermediate objectives were pursued in parallel:
- Production of a 3-D transport model for any conservative passive constituent, incorporating improved representations of the necessary physics - hydrodynamics and dispersion;
- Identifying and quantifying non-conservative processes - sources and sinks determining the cycling and fate of individual constituents;
- Defining a complete seasonal cycle as a database for all the observational studies needed to formulate, drive and test models.
Proudman Oceanographic Laboratory hosted the project, which involved over 200 scientists and support staff from NERC and other Government funded laboratories, as well as seven universities and polytechnics.
The project ran from 1987 to 1992, with marine field data collection between April 1988 and October 1989. One shakedown (CH28) and fifteen survey cruises (Table 1), each lasting 12 days and following the same track, were repeated monthly. The track selected covered the summer-stratified waters of the north and the homogeneous waters in the Southern Bight in about equal lengths together with their separating frontal band from Flamborough head to Dogger Bank, the Friesian Islands and the German Bight. Mooring stations were maintained at six sites for the duration of the project.
|Table 1: Details of NSP Survey Cruises on RRS Challenger|
|CH28||29/04/88 - 15/05/88|
|CH33||04/08/88 - 16/08/88|
|CH35||03/09/88 - 15/09/88|
|CH37||02/10/88 - 14/10/88|
|CH39||01/11/88 - 13/11/88|
|CH41||01/12/88 - 13/12/88|
|CH43||30/12/88 - 12/01/89|
|CH45||28/01/89 - 10/02/89|
|CH47||27/02/89 - 12/03/89|
|CH49||29/03/89 - 10/04/89|
|CH51||27/04/89 - 09/05/89|
|CH53||26/05/89 - 07/06/89|
|CH55||24/06/89 - 07/07/89|
|CH57||24/07/89 - 06/08/89|
|CH59||23/08/89 - 04/09/89|
|CH61||21/09/89 - 03/10/89|
Alternating with the survey cruises were process study cruises (Table 2), which investigated some particular aspect of the science of the North Sea. These included fronts (nearshore, circulation and mixing), sandwaves and sandbanks, plumes (Humber, Wash, Thames and Rhine), resuspension, air-sea exchange, primary productivity and blooms/chemistry.
|Table 2: Details of NSP Process cruises on RRS Challenger|
|CH34||18/08/88 - 01/09/88||Fronts - nearshore|
|CH36||16/09/88 - 30/09/88||Fronts - mixing|
|CH56||08/07/89 - 22/07/89||Fronts - circulation|
|CH58||07/08/89 - 21/08/89||Fronts - mixing|
|CH38||24/10/88 - 31/10/88||Sandwaves|
|CH40||15/11/88 - 29/11/88||Sandbanks|
|CH42||15/12/88 - 29/12/88||Plumes/Sandbanks|
|CH46||12/02/89 - 26/02/89||Plumes/Sandwaves|
|CH44||13/01/89 - 27/01/89||Resuspension|
|CH52||11/05/89 - 24/05/89||Resuspension|
|CH60||06/09/89 - 19/09/89||Resuspension|
|CH48||13/03/89 - 27/03/89||Air/sea exchanges|
|CH62||05/10/89 - 19/10/89||Air/sea exchanges|
|CH50||12/04/89 - 25/04/89||Blooms/chemistry|
|CH54||09/06/89 - 22/06/89||Production|
In addition to the main data collection period, a series of cruises took place between October 1989 and October 1990 that followed up work done on previous cruises (Table 3). Process studies relating to blooms, plumes (Humber, Wash and Rhine), sandwaves and the flux of contaminants through the Dover Strait were carried out as well as two `survey' cruises.
|Table 3: Details of NSP `Follow up' cruises on RRS Challenger|
|CH62A||23/10/89 - 03/11/89||Blooms|
|CH64||03/04/90 - 03/05/90||Blooms|
|CH65||06/05/90 - 17/05/90||Humber plume|
|CH66A||20/05/90 - 31/05/90||Survey|
|CH66B||03/06/90 - 18/06/90||Contaminants through Dover Strait|
|CH69||26/07/90 - 07/08/90||Resuspension/Plumes|
|CH72A||20/09/90 - 02/10/90||Survey|
|CH72B||04/10/90 - 06/10/90||Sandwaves/STABLE|
|CH72C||06/10/90 - 19/10/90||Rhine plume|
The data collected during the observational phase of the North Sea Project comprised one of the most detailed sets of observations ever undertaken in any shallow shelf sea at that time.
|Start Date (yyyy-mm-dd)||1988-09-18|
|End Date (yyyy-mm-dd)||1988-10-09|
|Organization Undertaking Activity||Institute of Oceanographic Sciences Bidston Laboratory (now National Oceanography Centre, Liverpool)|
|Country of Organization||United Kingdom|
|Originator's Data Activity Identifier||C36CC|
|Platform Category||subsurface mooring|
North Sea Project Data Activity: POLRIG#C36CC
This rig was deployed as part of the NERC North Sea Project Survey at Station C.
|Rig position||54 ° 20.62N 0 ° 23.69E|
The mooring contained two instruments, an Acoustic Doppler Current Profiler (ADCP) and an Aanderaa (RCM4) current meter. These were mounted on a frame positioned on the seabed, which was equipped with an IOS acoustic release. At the end of the deployment, acoustic signals sent from the ship triggered the release so that the frame separated from the ballast weight. The frame, under its own buoyancy (glass spheres), then rose to the surface ready for recovery.
|Instrument||Meter height||Parameters measured|
|RCM4 A7570||0.8m||Conductivity, pressure and temperature|
|ADCP D0001||0.8m||Corrupt data|
Fixed Station Information
|Station Name||NSP Survey C and CTD Site DM|
|Latitude||54° 19.80' N|
|Longitude||0° 24.00' E|
|Water depth below MSL||60.0 m|
North Sea Project Survey Mooring Site C and CTD Site DM
Site C was one of six fixed stations where moorings were deployed during the North Sea Project Survey. This location is also one of 123 North Sea Project CTD Sites.
The site was characterised by moderate tidal currents, up to a maximum of 1.1 m/s. In summer months, the site was situated in a frontal region between stratified water to the north and vertically well mixed water to the south.
The rigs deployed here lie within a box bounded by co-ordinates 54.32N 0.393E at the southwest corner and 54.34N 0.422E at the northeast corner. Magnetic variation at this site was 4.9° west.
Site C deployment history is summarised below:
|Rig ID||Meter type||Meter height||Start date||Data return (days)||Comment|
|C49CT||THCH||08/04/89||28||Data for 5.0m thermistor bead only|
|C51CT||THCH||06/05/89||29||Data for 5.0m thermistor bead only|
|C53CT||THCH||04/06/89||29||All data except, 5.0m thermistor bead data, extremely 'noisy'|
Rig trawled 01/08/89
Rig trawled 01/08/89
|C57CT||THCH||05/08/89||27||Good data in all but 2 thermistor bead depths|
|C59CT||THCH||01/09/89||29||Good data in all but 3 thermistor bead depths|
ADCP = Acoustic Doppler Current Profiler
CM = Current Meter (Aanderaa or S4)
THCH = Thermistor Chain
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: NSP Survey C and CTD Site DM
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|
|580058||Hydrography time series at depth||1988-08-13 19:59:59||54.3317 N, 0.4035 E||Not applicable|
|604959||Hydrography time series at depth||1988-08-13 20:30:00||54.3317 N, 0.4 E||Not applicable|
|769888||CTD or STD cast||1988-08-13 20:32:00||54.32933 N, 0.40117 E||RRS Challenger CH33|
|770017||CTD or STD cast||1988-08-15 01:44:00||54.31817 N, 0.47 E||RRS Challenger CH33|
|811184||CTD or STD cast||1988-08-27 22:16:00||54.336 N, 0.34383 E||RRS Challenger CH34|
|783986||CTD or STD cast||1988-09-12 08:38:00||54.3335 N, 0.402 E||RRS Challenger CH35|
|605011||Hydrography time series at depth||1988-09-12 09:40:38||54.3348 N, 0.3988 E||Not applicable|
|812010||CTD or STD cast||1988-09-18 20:03:00||54.33167 N, 0.39467 E||RRS Challenger CH36|
|784603||CTD or STD cast||1988-10-09 12:52:00||54.3295 N, 0.43017 E||RRS Challenger CH37|
|580114||Hydrography time series at depth||1988-10-09 14:50:00||54.3332 N, 0.4037 E||Not applicable|
|604100||Currents -subsurface Eulerian||1988-10-09 14:57:12||54.3332 N, 0.4037 E||Not applicable|
|580102||Hydrography time series at depth||1988-11-10 08:00:01||54.334 N, 0.4098 E||Not applicable|
|604093||Currents -subsurface Eulerian||1988-11-10 08:07:06||54.334 N, 0.4098 E||Not applicable|
|822305||CTD or STD cast||1988-11-11 18:44:00||54.33167 N, 0.3995 E||RRS Challenger CH39|
|785225||CTD or STD cast||1988-12-07 08:58:00||54.3205 N, 0.397 E||RRS Challenger CH41|
|580071||Hydrography time series at depth||1988-12-07 12:40:00||54.3327 N, 0.417 E||Not applicable|
|785993||CTD or STD cast||1989-01-01 09:00:00||54.332 N, 0.40133 E||RRS Challenger CH43|
|604020||Currents -subsurface Eulerian||1989-01-01 11:17:13||54.3318 N, 0.4217 E||Not applicable|
|791949||CTD or STD cast||1989-02-07 12:44:00||54.33317 N, 0.39383 E||RRS Challenger CH45|
|604019||Currents -subsurface Eulerian||1989-02-07 14:16:49||54.3327 N, 0.421 E||Not applicable|
|793089||CTD or STD cast||1989-03-07 06:32:00||54.33267 N, 0.39767 E||RRS Challenger CH47|
|1857825||Water sample data||1989-03-07 06:35:00||54.33264 N, 0.39771 E||RRS Challenger CH47|
|793680||CTD or STD cast||1989-03-07 06:52:00||54.33367 N, 0.40333 E||RRS Challenger CH47|
|604068||Currents -subsurface Eulerian||1989-03-09 15:16:57||54.3302 N, 0.3975 E||Not applicable|
|793378||CTD or STD cast||1989-03-09 15:24:00||54.32767 N, 0.39667 E||RRS Challenger CH47|
|1858110||Water sample data||1989-03-09 15:27:00||54.32767 N, 0.39662 E||RRS Challenger CH47|
|604947||Hydrography time series at depth||1989-04-08 09:29:57||54.3377 N, 0.4027 E||Not applicable|
|603993||Currents -subsurface Eulerian||1989-04-08 09:37:06||54.33 N, 0.3993 E||Not applicable|
|591751||Currents -subsurface Eulerian||1989-04-08 09:40:00||54.33 N, 0.3993 E||Not applicable|
|794505||CTD or STD cast||1989-04-08 09:52:00||54.33383 N, 0.39733 E||RRS Challenger CH49|
|1859186||Water sample data||1989-04-08 09:56:00||54.33377 N, 0.3974 E||RRS Challenger CH49|
|795613||CTD or STD cast||1989-05-06 15:13:00||54.33033 N, 0.40067 E||RRS Challenger CH51|
|1861455||Water sample data||1989-05-06 15:24:00||54.33025 N, 0.40067 E||RRS Challenger CH51|
|604996||Hydrography time series at depth||1989-05-06 16:26:15||54.3285 N, 0.4043 E||Not applicable|
|591787||Currents -subsurface Eulerian||1989-05-06 16:50:00||54.331 N, 0.4035 E||Not applicable|
|604081||Currents -subsurface Eulerian||1989-05-06 16:57:08||54.331 N, 0.4035 E||Not applicable|
|796991||CTD or STD cast||1989-06-04 06:44:00||54.33033 N, 0.40117 E||RRS Challenger CH53|
|1864035||Water sample data||1989-06-04 06:49:00||54.33041 N, 0.40124 E||RRS Challenger CH53|
|604984||Hydrography time series at depth||1989-06-04 07:58:08||54.3385 N, 0.3965 E||Not applicable|
|604044||Currents -subsurface Eulerian||1989-06-04 08:07:08||54.3403 N, 0.3938 E||Not applicable|
|580083||Hydrography time series at depth||1989-06-04 08:10:02||54.3403 N, 0.3938 E||Not applicable|
|798266||CTD or STD cast||1989-07-03 03:22:00||54.3315 N, 0.4015 E||RRS Challenger CH55|
|1657208||Water sample data||1989-07-03 03:28:00||54.33154 N, 0.40146 E||RRS Challenger CH55|
|1866484||Water sample data||1989-07-03 03:28:00||54.33154 N, 0.40146 E||RRS Challenger CH55|
|604972||Hydrography time series at depth||1989-07-03 05:41:30||54.3372 N, 0.3962 E||Not applicable|
|591775||Currents -subsurface Eulerian||1989-07-03 05:47:00||54.3398 N, 0.395 E||Not applicable|
|604032||Currents -subsurface Eulerian||1989-07-03 05:47:11||54.3398 N, 0.395 E||Not applicable|
|799743||CTD or STD cast||1989-08-05 05:16:00||54.33283 N, 0.4185 E||RRS Challenger CH57|
|1246556||Water sample data||1989-08-05 05:19:00||54.33279 N, 0.41858 E||RRS Challenger CH57|
|1710012||Water sample data||1989-08-05 05:19:00||54.33279 N, 0.41858 E||RRS Challenger CH57|
|1865388||Water sample data||1989-08-05 05:19:00||54.33279 N, 0.41858 E||RRS Challenger CH57|
|591763||Currents -subsurface Eulerian||1989-08-05 06:50:00||54.34 N, 0.396 E||Not applicable|
|604960||Hydrography time series at depth||1989-08-05 06:50:39||54.3367 N, 0.3983 E||Not applicable|
|604007||Currents -subsurface Eulerian||1989-08-05 06:57:10||54.34 N, 0.396 E||Not applicable|
|802156||CTD or STD cast||1989-09-01 03:13:00||54.33067 N, 0.40533 E||RRS Challenger CH59|
|1856846||Water sample data||1989-09-01 03:19:00||54.3306 N, 0.4053 E||RRS Challenger CH59|
|605023||Hydrography time series at depth||1989-09-01 06:48:10||54.337 N, 0.4003 E||Not applicable|
|591799||Currents -subsurface Eulerian||1989-09-01 07:05:00||54.3405 N, 0.399 E||Not applicable|
|604124||Currents -subsurface Eulerian||1989-09-01 07:07:11||54.3405 N, 0.399 E||Not applicable|
|800819||CTD or STD cast||1989-09-30 17:01:00||54.33517 N, 0.40267 E||RRS Challenger CH61|
|1855578||Water sample data||1989-09-30 17:05:00||54.33516 N, 0.40264 E||RRS Challenger CH61|
|805302||CTD or STD cast||1990-10-01 09:23:00||54.333 N, 0.397 E||RRS Challenger CH72A|