Metadata Report for BODC Series Reference Number 1623015
Metadata Summary
Problem Reports
Data Access Policy
Narrative Documents
Project Information
Data Activity or Cruise Information
Fixed Station Information
BODC Quality Flags
SeaDataNet Quality Flags
Metadata Summary
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Time Co-ordinates(UT) |
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Problem Reports
No Problem Report Found in the Database
Data Access Policy
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."
Narrative Documents
Aanderaa Recording Current Meter Model 7/8
Manufacturer's specifications: recording unit height 49.5cm (RCM8 52.0cm), diameter 12.8cm, vane size 48.5x50.0cm. Meter is designed for depths down to 2000m (RCM8 6000m). It incorporates a spindle which is shackled to 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 :
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Paddle wheel rotor magnetically coupled to an electronic counter
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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.
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Magnetic compass (needle is clamped to potentiometer ring) - direction recorded with 0.35° resolution, 5° accuracy for speeds 5 to 100cm/s, 7.5° accuracy for remaining speeds within 2.5 to 200cm/s range.
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Quartz clock, accuracy better than 2 sec/day within temperature range 0 to 20°C.
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Thermistor (temperature sensor), standard range -2.46 to 21.48°C (max on high range 36.04°C), accuracy 0.05°C, resolution 0.1 per cent of range, 63 per cent response time 12sec.
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Inductive cell conductivity sensor (optional), range 0 to 70mmho/cm standard resolution 0.1 per cent of range.
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Silicon piezoresistive bridge, standard range 0 to 3000 psi (RCM8 to 9000 psi), resolution 0.1% of range.
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Self balancing potentiometer which converts the output from each sensor into a 10 bit binary number for storage on magnetic tape.
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Associated electronics.
A built-in clock triggers the instrument at preset intervals and up to six channels are sampled in sequence. Channel 1 is a fixed reference reading for control purposes and data identification. Channels 2, 3 and 4 represent measurement of temperature, conductivity and pressure. Channels 5 and 6 represent the VECTOR AVERAGED current speed and direction since the previous triggering of the instrument. The number of rotor revolutions and the direction is sampled every 12 seconds and broken into North and East components. Successive components are added and recorded as speed and direction. For recording intervals longer than 10 minutes, speed and direction are sampled 1/50th of recording interval.
It has become common practice in some laboratories to deploy these meters as temperature and conductivity loggers without current measuring capabilities.
The following link will provide the manufacturer specifications:
Manufacturer specificationsBODC Processing
The data were received in Pstar format and converted into BODC internal format following BODC's standard procedures. The following table shows how the variables within the Pstar file were mapped to appropriate BODC parameter codes:
Originator's Parameter Name | Units | Description | BODC Parameter Code | Units | Comments |
---|---|---|---|---|---|
time | Julian day and hhmmss | Date and time | - | - | - |
dayofNov | Decimal days | Date and time | - | - | - |
crsetemp | - | Unknown | - | - | - |
cond | mS cm-1 | Conductivity | CNDCZZ01 | S m-1 | Units converted from mS cm-1 to S m-1 by dividing by 10. |
temp | °C | Temperature | TEMPPR01 | °C | - |
dirn | Degrees | Current direction | LCDAZZ01 | Degrees | - |
speed | cm s-1 | Current speed | LCSAEL01 | cm s-1 | - |
east | cm s-1 | Eastward current velocity | LCEWEL01 | cm s-1 | - |
north | cm s-1 | Northward current velocity | LCNSEL01 | cm s-1 | - |
depth | m | Instrument depth | ADEPPS01 | m | - |
press | dbar | Pressure | PRSTPR01 | dbar | - |
salin | Dimensionless | Salinity | PSALPR01 | Dimensionless | - |
potemp | °C | Potential temperature | POTMCV01 | °C | - |
All reformatted data were visualised using the in-house Edserplo software. Suspect and missing data were marked by adding an appropriate quality control flag.
Originator's Data Processing
Sampling Strategy
Data from a Aanderaa RCM 8 current meter were collected on a mooring deployed during the Crozex cruise D285. The mooring was deployed at site M3 north of the Crozet Islands. On arrival at M3 the ship ran south along a ridge on which the mooring was set. The ridge had been chosen from a detailed French chart and a swath bathymetry survey, and the latter proved accurate to pinpoint the ridge crest, as verified by a second pass from west to east.
Data Processing
All instruments were downloaded onboard and preliminary plots made. The data were converted into Pstar format, a binary format used by NOC physical oceanographers to process, plot and archive a range of oceanographic data. No further details about the data processing were provided.
Project Information
CROZet natural iron bloom EXport experiment (CROZEX)
The multidisciplinary CROZet natural iron bloom EXport experiment (CROZEX) was a major component of the Natural Environment Research Council (NERC) funded core strategic project Biophysical Interactions and Controls over Export Production (BICEP). The project is the first planned natural iron fertilisation experiment to have been conducted in the Southern Ocean.
The overall objective of CROZEX was to examine, from surface to sediment, the structure, causes and consequences of a naturally occurring phytoplankton bloom in the Southern Ocean. The Crozet Plateau was chosen as the study area. This area typically exhibits two phytoplankton blooms a year, a primary bloom in that peaks in October and a secondary bloom in December or January. Specific aims with respect to these were to:
- Determine what limits the primary bloom
- Determine the cause of the secondary bloom
The project was run by the George Deacon Division (GDD), now Ocean Biogeochemistry and Ecosystems (OBE) at the National Oceanography Centre Southampton (NOCS). Participants from five other university departments also contributed to the project.
The project ran from November 2004 to January 2008 with marine data collection between 3rd November 2004 and 21st January 2005. There were 2 cruises to the Crozet Islands Plateau, which are summarised in Table 1.
Table 1: Details of the RRS Discovery CROZEX cruises.
Cruise No. | Dates |
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D285 | 3rd November 2004 - 10th December 2004 |
D286 | 13th December 2004 - 21st January 2005 |
The two cruises aimed to survey two areas at different phases of the bloom cycle described above. A control area to the south of the Crozet Islands, which is classified as High Nutrient Low Chorophyll (HNLC), where the blooms do not occur and a second area in the region of the blooms to the north of the Crozet Islands.
Sampling was undertaken at ten major stations (see Pollard et al., 2007) numbered M1 to M10. The following observations/sampling were conducted at each station where possible:
- Several CTD casts sampling:
- Iron (using a titanium rig)
- 234Th
- Physical parameters (temperature, salinity etc)
- Oxygen
- CO2
- Nutrients using a stainless steel rig including a Lowered Acoustic Doppler Current Profiller (LADCP)
- At each thorium cast there was an associated Stand Alone Pump System (SAPS) deployment
- At some stations, a drifting PELAGRA trap was deployed for the duration of the work
- Megacoring was undertaken at M5 and M6
- Gravity coring was undertaken at M5, M6 and M10
- Longhurst Hardy Plankton Recorder (LPHR) tows were undertaken at a few major stations
For each of the major stations (M1 to M10), the following were determined:
- Primary productivity
- New Production
- Phytoplankton community composition
- Bacterial activity
- Iron
- Nutrient drawdown
- Thorium export
Sampling between major stations included:
- SeaSoar runs instrumented with:
- CTD
- Optical Plankton Counter (OPC)
- Fast Repetition Rate fluorimeter (FRRf)
- Physics CTD casts on several lines
- Argo float deployments
- Zooplankton nets at nearly every CTD and major station
- Underway and on-station CO2 measurements
- Underway nutrients and radium sampling
- 5 to 6 day ship-board iron-addition incubation experiments
- Checks against near-real-time satellite and model data
- Mooring deployments based on the satellite imagery in support of the CROZET (Benthic CROZEX) project.
The CROZEX cruises included 6 extra days in support of the CROZET (Benthic CROZEX) project, whose main cruise took place one year after the CROZEX cruises. The CROZET work undertaken during the CROZEX cruises was primarily the moored sediment trap deployments, although some of the coring work is applicable to both projects.
CROZEX produced significant findings in several disciplines, including confirmation that iron from Crozet fertilised the bloom and that phytoplankton production rates and most export flux estimates were much larger in the bloom area than the HNLC area (Pollard et al. 2007). Many of the project results are presented in a special CROZEX issue of Deep-Sea Research II (volume 54, 2007).
References
Pollard R., Sanders R., Lucas M. and Statham P., 2007. The Crozet natural iron bloom and export experiment (CROZEX). Deep-Sea Research II, 54, 1905-1914.
Data Activity or Cruise Information
Data Activity
Start Date (yyyy-mm-dd) | 2004-11-13 |
End Date (yyyy-mm-dd) | 2005-01-09 |
Organization Undertaking Activity | Southampton Oceanography Centre (now National Oceanography Centre, Southampton) |
Country of Organization | United Kingdom |
Originator's Data Activity Identifier | Mooring_M3 |
Platform Category | subsurface mooring |
CROZEX D285 Moored Instrument M3
Deployed (UT) | 2004-11-13 05:50:00 |
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Latitude (+ve N) | -46.0578 |
Longitude (+ve E) | 51.72613 |
Recovered (UT) | 2005-01-09 13:50:00 |
The mooring also comprised an Acoustic Doppler Current Profiler (ADCP) and additional current meters with a distributed buoyancy and steel wire. On top of this was an additional CT mooring which comprised Sea-Bird 37-SMP MicroCAT C-T units clamped to a parallel fibre kevlar line. Simple steel support buoyancy supported this section and minimum depth of sphere and upper sensor was aimed at 50 metres depth. All mooring lines were measured when winding onto the DBC system prior to deployment. An ARGOS SMM beacon was monitored using the RDF receiver to ensure that the top buoy fully submerged.At suitable depths Thorium sampling bags were added from 50 metres depth to 1930 metres depth.
Deployment was carried out buoy first and anchor freefall last. UKORS DBC and reeler system and the ship's aft crane were used for deployment.
Instruments deployed on the rig
Depth (m) | Instruments | Serial numbers |
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50 | Sea-Bird SBE 37-SMP MicroCAT C-T sensor | 3479 |
100 | Sea-Bird SBE 37-SMP MicroCAT C-T sensor | 3485 |
150 | Sea-Bird SBE 37-SMP MicroCAT C-T sensor | 3480 |
200 | Sea-Bird SBE 37-SMP MicroCAT C-T sensor | 3487 |
300 | Sea-Bird SBE 37-SMP MicroCAT C-T sensor | 3482 |
500 | Aanderaa RCM 8 recording current meter Teledyne RDI Workhorse Long-Ranger ADCP | 11047 WHLS75-I-2 5476 |
904 | SonTek Argonaut moored 3D doppler current meter fitted with a Sea-Bird SBE 37-SI MicroCAT C-T sensor | 319 and SBE 3361 |
1300 | Aanderaa RCM 11 recording current meter | 426 |
1940 | SonTek Argonaut moored 3D doppler current meter fitted with a Sea-Bird SBE 37-SI MicroCAT C-T sensor | 320 and SBE 3376 |
The mooring performed well and the depths of the instruments were within design parameters. The RCM 8 had some water ingress, but had run a complete data record. The cause of this water ingress may have been due to water entering during the recovery operation when the current meter took severe impact with the ADCP buoy as it fell back into the sea. Also the main battery terminals had jumped off indicating that the impact was quite severe. The data appear to be unaffected.
Cruise
Cruise Name | D285 |
Departure Date | 2004-11-03 |
Arrival Date | 2004-12-10 |
Principal Scientist(s) | Raymond T Pollard (Southampton Oceanography Centre) |
Ship | RRS Discovery |
Complete Cruise Metadata Report is available here
Fixed Station Information
No Fixed Station Information held for the Series
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 |
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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 |
SeaDataNet Quality Control Flags
The following single character qualifying flags may be associated with one or more individual parameters with a data cycle:
Flag | Description |
---|---|
0 | no quality control |
1 | good value |
2 | probably good value |
3 | probably bad value |
4 | bad value |
5 | changed value |
6 | value below detection |
7 | value in excess |
8 | interpolated value |
9 | missing value |
A | value phenomenon uncertain |
B | nominal value |
Q | value below limit of quantification |