Metadata Report for BODC Series Reference Number 696351
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
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 16plus SEACAT with RS-485 Interface
The SBE 16plus is a high accuracy conductivity and temperature recorder (pressure optional). It is designed for moorings and other long-duration, fixed-site deployments. The SBE 16plus has 6 amplified A/D input channels and conditioned power of 500 ma is avaliable for auxiliary sensors, dissolved oxygen, turbidity, fluorescence, PAR etc.
Specifications
| Temperature (°C) | Conductivity (S m-1) | Optional Pressure - strain Gauge | Optional Pressure - Quartz | |
|---|---|---|---|---|
| Measurement Range | -5 to +35 | 0 to 9 | 0 to full scale range: 20 / 100 / 350 / 1000 / 1600 / 2000 / 3500 / 7000 metres | 0 to full scale range: 20 / 60 / 130 / 200 / 270 / 680 / 1400 / 2000 / 4200 / 7000 / 10500 metres |
| Initial accuracy | 0.005 | 0.0005 | 0.04% of full scale range | 0.002% of full scale range |
| Typical Stability | 0.0002 | 0.0003 | 0.1% of full scale range | 0.025% of full scale range |
| Resolution | 0.0001 | 0.00005 typical | 0.002% of full scale range | Depends on sample integration, 0.0006% of full scale range for 1 s integration |
| Sensor Calibration | +1 to +32 | 0 to 9; physical calibration over range 2.6 to 6.5 S m-1 plus zero conductivity (air) | Ambient pressure to full scale range in 5 steps | Ambient pressure to full scale range in 5 steps |
| Memory | 64 MB FLASH memory | |||
| Data Storage | Converted temperature and conductivity: 6 bytes per sample Time: 4 bytes per sample Pressure (optional): 5 bytes per sample | |||
| Real-Time Clock | Watch-crystal type 32,768 Hz; accuracy (±1 minutes/year) | |||
| Standard Internal Batteries | 9 alkaline D-cells. Provides sufficient capacity for 145,000 samples for a CTD and 5M pump | |||
| Housing | Titanium pressure case rated at 7000 metres | |||
| Weight (without pressure) | In water: 8.6 kg In air: 13.7 kg | |||
Further information can be found via the following link: Official SBE 16plus Manual
Seapoint Turbidity Meter
The Seapoint Turbidity Meter detects light scattered by particles suspended in water, generating an output voltage proportional to turbidity or suspended solids. Range is selected by two digital lines which can be hard wired or microprocessor controlled, thereby choosing the appropriate range and resolution for measurement of extremely clean to very turbid waters. The offset voltage is within 1 mV of zero and requires no adjustment across gains. The optical design confines the sensing volume to within 5 cm of the sensor allowing near-bottom measurements and minimizing errant reflections in restricted spaces.
Sensor specifications, current at August 2006, are given in the table below.
Sensor Specifications
| Power requirements | 7 - 20 VDC, 3.5 mA avg., 6 mA pk. |
|---|---|
| Output | 0 - 5.0 VDC |
| Output Time Constant | 0.1 sec. |
| RMS Noise> | < 1 mV |
| Power-up transient period | < 1 sec. |
| Light Source Wavelength | 880 nm |
| Sensing Distance (from windows) | < 5 cm (approx.) |
| Linearity | < 2% deviation 0 - 750 FTU |
| Gain | Sensitivity (mV FTU-1) | Range (FTU) | |
|---|---|---|---|
| Sensitivity/Range | 100x 20x 5x 1x | 200 40 10 2 | 25 125 500 ** |
** output is non-linear above 750 FTU.
Further details can be found in the manufacturer's specification sheet.
Data Processing: NOCL Sea-Bird SBE 16plus SEACAT with Seapoint Turbidity Sensor
Data Originator's Processing
The following procedures were carried out before the data were supplied to BODC.
Data were downloaded by the Proudman Oceanographic Laboratory (POL) [since 01 April 2010, the National Oceanography Centre Liverpool (NOCL)] from the instrument logger, and factory calibrations were applied to the temperature and conductivity channels. The instruments are returned to the manufacturer for recalibration approximately every two years.
The data were then reformatted by POL/NOCL to a standard ASCII format for display on the Coastal Observatory website. The originator carried out limited quality control checks, which involved looking for obvious anomalies in the data, cross-checking against other datasets and timing checks.
BODC Data Processing
The data files (ASCII format) were downloaded by BODC from the POL Coastal Observatory web site. The files were reformatted to qxf format using BODC transfer function 318. The following table shows how the originator's variables were mapped to appropriate BODC parameter codes:
| Originator's Variable | Units | Description | BODC Parameter Code | Units | Comments |
|---|---|---|---|---|---|
| Temperature | °C | Temperature of the water column | TEMPPR01 | °C | Data supplied as ITS-90 |
| Conductivity | S m-1 | Electrical conductivity of the water column by in-situ conductivity cell | CNDCPR01 | S m-1 | - |
| Pressure | dbar | Pressure exerted by the water column | PREXPS01 | dbar | - |
| Turbidity | FTU | Turbidity of the water column by Seapoint turbidity meter and laboratory calibration against formazin | TURBSP01 | NTU | FTU=NTU |
| - | - | Practical salinity of the water column by conductivity cell and computation using UNESCO 1983 algorithm | PSALPR01 | - | Derived at BODC during transfer from MATLAB Seawater Toolbox program 'sw_salt'. This uses UNESCO 1983 algorithm (see reference) |
Salinity calculation
Salinity (PSS-78) was computed during transfer using the MATLAB sw_salt routine:
- salinity=sw_salt((cond(*10)/sw_c3515,temp*1.00024,pres)
where
- cond = in-situ conductivity
- sw_c3515: MATLAB function that returns conductivity at Salinity = 35, Temperature = 15 °C (IPTS-68) and Pressure = 0 dbar
- temp = in-situ temperature (ITS-90)
- 1.00024 = factor to convert temperature from ITS-90 intoIPTS-68, which is required for the calculation of salinity using this routine.
- pres = in-situ pressure.
Quality control
The reformatted data were visualised using the in-house EDSERPLO software. Suspect and missing data were marked by adding appropriate quality control flags.
References
Fofonoff, N.P., and R.C. Millard Jr., 1983 "Algorithms for computation of fundamental properties of seawater", UNESCO technical paper in marine science 44, 53pp.
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.
Project Information
Proudman Oceanographic Laboratory Coastal Observatory
The Coastal Observatory was established by Proudman Oceanographic Laboratory as a coastal zone real time observing and monitoring system. The main objective is to understand a coastal sea's response both to natural forcing and to the consequences of human activity. Near real-time measurements will be integrated with coupled models into a pre-operational coastal prediction system whose results will be displayed on the World Wide Web.
The Observatory is expected to grow and evolve as resources and technology allow, all the while building up long time series. A site selection pilot study was carried out in September 2001 and the Observatory became operational in August 2002.
The site is located in Liverpool Bay and is subject to typical coastal sea processes, with strong tides, occasional large storm surges and waves, freshwater input, stable and unstable stratification, high suspended sediment concentration and biogeochemical interaction. Measurements and monitoring will focus on the impacts of storms, variations in river discharge (especially the Mersey), seasonality and blooms in Liverpool Bay.
A variety of methods will be used to obtain measurements, including:
- Moored instruments for in situ time series of currents, temperature and salinity profiles, and surface waves and meteorology. It is hoped that turbidity and chlorophyll measurements will be made at another site as the Observatory progresses;
- The Cefas Smartbuoy for surface properties such as nutrients and chlorophyll, starting late 2002;
- R.V. Prince Madog to carry out spatial surveys and service moorings;
- Instrumented ferries for near surface temperature, salinity, turbidity, chlorophyll and nutrients. The first route will be Liverpool to Douglas, Isle of Man, starting late 2002;
- Drifters for surface currents and properties such as temperature and salinity, starting in 2004;
- Tide gauges, with sensors for meteorology, waves, temperature and salinity, where appropriate;
- Meteorological data from Bidston Observatory, HF radar and tide gauge sites;
- Shore-based HF radar measuring waves and surface currents out to a range of 50 km, starting in 2003;
- Satellite data, with infrared for sea surface temperature and visible for chlorophyll and suspended sediment.
The partners currently involved with the project are listed below:
- Proudman Oceanographic Laboratory
- British Oceanographic Data Centre
- UK Meteorological Office
- Centre for Environment, Fisheries and Aquaculture Science
- Environment Agency
- Liverpool University and Port Erin Marine Laboratory
- Bangor University School of Ocean Sciences
- National Oceanography Centre Southampton
- Department of Agriculture and Rural Development in Northern Ireland
A summary of Coastal Observatory cruises to date on R.V. Prince Madog is given in the table below:
| Year | No. of cruises | Work summary |
|---|---|---|
| 2001 | 1 | Site selection and pilot study. 95 CTD casts. |
| 2002 | 4 | POL moorings deployed and serviced Cefas Waverider and SmartBuoy deployed and serviced 103 CTD casts |
| 2003 | 10 | POL moorings serviced Cefas Waverider and SmartBuoy serviced 341 CTD/LISST casts |
| 2004 | 9 | POL moorings serviced Cefas Waverider and SmartBuoy serviced 347 CTD/LISST casts |
| 2005 | 9 | POL moorings serviced Cefas Waverider and SmartBuoy serviced 268 CTD/LISST casts |
| 2006 | 11 | POL moorings serviced Cefas Waverider and SmartBuoy serviced 508 CTD/LISST casts |
| 2007 | 9 | POL moorings serviced Cefas Waverider and SmartBuoy serviced 471 CTD/LISST casts |
| 2008 | 9 | POL moorings serviced Cefas Waverider and SmartBuoy serviced 260 CTD/LISST casts |
| 2009 | 7 | POL moorings serviced Cefas Waverider and SmartBuoy serviced 213 CTD/LISST casts |
| 2010 | 8 | POL moorings serviced Cefas Waverider and SmartBuoy serviced 268 CTD/LISST casts |
| 2011 | 6 | POL moorings serviced Cefas Waverider and SmartBuoy serviced 307 CTD/LISST casts to date, ongoing |
Data Activity or Cruise Information
Data Activity
| Start Date (yyyy-mm-dd) | 2005-12-14 |
| End Date (yyyy-mm-dd) | 2006-09-06 |
| Organization Undertaking Activity | Proudman Oceanographic Laboratory (now National Oceanography Centre, Liverpool) |
| Country of Organization | United Kingdom |
| Originator's Data Activity Identifier | POLRIG#950 |
| Platform Category | fixed benthic node |
Proudman Oceanographic Laboratory Rig#950
Deployment and Recovery
This rig was deployed as part of the Liverpool Bay Coastal Observatory during R.V. Prince Madog cruise PD48_05. Recovery of the rig took place during R.V. Prince Madog cruise PD04_06.
Deployment details are given in the table below. Date and time are in Universal Time (UT) and are displayed in the ISO format YYYY-MM-DD hh:mm.
| Rig Position | 53° 26.997' N, 3° 39.481' W |
|---|---|
| Water Depth | 29.0 m |
| Deployed (UT) | 2005-12-14 10:45 |
| Recovered (UT) | 2006-02-06 14:35 |
| No. of Days | 52 |
Rig Description
This rig was a bottom frame with the following instruments mounted 0.5 m above the sea bed: Waves Acoustic Doppler Current Profiler (ADCP), Sea-Bird 16plus, Telemetry ADCP and a Telemetry buoy with a LinkQuest modem. The frame (D1) was fitted with two Benthos releases with fizz links and a spooler with 200 m of rope for recovery of the ballast weight.
| Instrument | Serial Number | Parameters Measured | Sampling Description | Comments |
|---|---|---|---|---|
| RDI Waves ADCP 600 kHz | 5803 | Horizontal current velocity components Vertical current velocity components Temperature Pressure | Mode 1: 100 pings every 10 minutes (velocity standard deviation 0.007 m s-1). 35 x 1 m bins (2.65 - 36.65 m above the bed) | Sound velocity calculated from temperature, depth and salinity of 32. Fitted with a pressure sensor and 1 Gbyte PCMCIA memory; hourly wave recording enabled. |
| Sea-Bird 16plus V RS-485 1.0 | 4738 | Temperature Conductivity Pressure Turbidity | Sample interval 600 s. | Fitted to base of frame with pumped conductivity sensor underneath. SeaPoint turbidity sensor: S/N 10320 taped to roll bar; set up for 0 - 25 FTU range (no cable available to set to 0 - 125 FTU range). |
| RDI Telemetry ADCP 1.2 MHz | 6489 | Horizontal current velocity components Vertical current velocity components Temperature Pressure | - | The telemetry buoy is fitted with an Orbcomm satellite system and a LinkQuest acoustic modem (serial number 8604). |
Cruise
| Cruise Name | PD48/05 |
| Departure Date | 2005-12-14 |
| Arrival Date | 2005-12-15 |
| Principal Scientist(s) | Phil J Knight (Proudman Oceanographic Laboratory) |
| Ship | RV Prince Madog |
Complete Cruise Metadata Report is available here
Fixed Station Information
Fixed Station Information
| Station Name | Coastal Observatory Site 21 |
| Category | Offshore location |
| Latitude | 53° 27.13' N |
| Longitude | 3° 38.48' W |
| Water depth below MSL | 25.0 m |
Liverpool Bay Coastal Observatory Site 21
This station is one of 34 stations regularly visited by the Proudman Oceanographic Laboratory (POL) as part of the Liverpool Bay Coastal Observatory. The main activity at this site are CTD profiles (since August 2002) which are taken during each site visit. This station was also the secondary mooring site (also referred to as Site B) for the Coastal Observatory project between April 2005 and March 2010. After March 2010 the moorings were moved to site 20. The station lies within a box of mean water depth 24 m with the following co-ordinates:
| Box Corner | Latitude (+ve North) | Longitude (+ve East) |
|---|---|---|
| North-west corner | 53.46028 | -3.658 |
| South-east corner | 53.44249 | -3.6105 |
The position of this station relative to the other POL Coastal Observatory sites can be seen from the figure below.
Mooring Deployment History
2010
| Rig Type | Typical Instruments | Rig IDs | Comment |
|---|---|---|---|
| Frame | ADCP, CTD, OBS, Telemetry ADCP | 1088, 1092, 1096, 1100, 1104, 1107, 1111 | January - December |
| SmartBuoy | CT, FL, OBS, BD | 1087, 1091, 1095, 1099, 1103, 1110, 1115 | January - December |
2009
| Rig Type | Typical Instruments | Rig IDs | Comment |
|---|---|---|---|
| Frame | ADCP, CTD, OBS, Telemetry ADCP | 1057, 1065, 1069, 1072, 1076, 1080, 1084 | January - December |
| SmartBuoy | CT, FL, OBS, BD | 1056, 1064, 1068, 1075, 1079, 1083 | January - December |
2008
| Rig Type | Typical Instruments | Rig IDs | Comment |
|---|---|---|---|
| Frame | ADCP, CTD, OBS, Telemetry ADCP | 1026, 1030, 1033, 1038, 1053 | January - December |
| SmartBuoy | CT, FL, OBS, BD | LB2_023/1025, LB2_024/1029, LB2_025/1034, LB2_026/1037, LB2_029/1052 | January - December |
2007
| Rig Type | Typical Instruments | Rig IDs | Comment |
|---|---|---|---|
| Frame | ADCP, CTD, OBS, Telemetry ADCP | 992, 999, 1002, 1007, 1012, 1019 | January - December |
| SmartBuoy | CT, FL, OBS, BD | 991, LB2_016/998, LB2_017/1003, LB2_018/1006, LB2_019/1011, LB2_020/1015, LB2_021/1018, LB2_022/1022 | January - December |
2006
| Rig Type | Typical Instruments | Rig IDs | Comment |
|---|---|---|---|
| Frame | ADCP, CTD, OBS, Telemetry ADCP | 952, 960, 964, 968, 972, 976, 980, 984, 988 | January - December |
| SmartBuoy | CT, FL, OBS, BD | LB2_006, LB2_007, LB2_008, LB2_009, LB2_010, LB2_011, LB2_012, LB2_013/983, LB2_014/987 | January - December |
2005
| Rig Type | Typical Instruments | Rig IDs | Comment |
|---|---|---|---|
| Frame | ADCP, CTD, OBS | 923, 927, 931, 936, 940, 943, 947, 950 | January - December |
| SmartBuoy | CT, FL, OBS, WMS | LB2_001/926, LB2_002/930, LB2_003/935, LB2_004/939, LB2_005/946 | May - December |
| Marker buoy | CT | 922 | April - May |
CTD Sampling History
| Year | Number of Cruises | Total Casts per year |
| 2011 | 1 | 1 |
| 2010 | 5 | 5 |
| 2009 | 7 | 18 |
| 2008 | 9 | 16 |
| 2007 | 8 | 17 |
| 2006 | 9 | 18 |
| 2005 | 9 | 14 |
| 2004 | 8 | 8 |
| 2003 | 9 | 9 |
| 2002 | 2 | 2 |
The CTD instrument package for these cruises was a Sea-Bird 911plus, with beam transmissometer, fluorometer, LICOR PAR sensor, LISST-25, and oxygen sensor.
Key
ADCP = Acoustic Doppler Current Profiler
BD = Bacterial degradation experiment
CT = Conductivity and temperature logger
CTD = Conductivity, temperature, depth sensor
FL = Fluorometer
OBS = Optical Backscatter Turbidity meter
Telemetry ADCP = ADCP sending data back to shore in real-time
WMS = Automatic water sampler
Other Cruises linked to this Fixed Station (with the number of series) - PD01/08 (11) PD02/07 (3) PD02/09B (11) PD02/10 (1) PD04/06 (3) PD04/07 (4) PD06/07 (8) PD07/08 (8) PD09/07 (8) PD09/08 (10) PD11/05 (2) PD11/11 (1) PD12/06 (3) PD12/09 (5) PD13/07 (10) PD14/08 (9) PD16/06 (3) PD16/07 (9) PD17/10 (1) PD18/05 (3) PD18/09 (5) PD19/08 (2) PD20/06 (3) PD20/07 (7) PD21/05 (3) PD21/10 (1) PD22/06 (3) PD23/07 (9) PD23/08 (7) PD24/09 (3) PD25/05 (3) PD25/06 (3) PD27/07 (9) PD29/06 (3) PD29/08 (8) PD29/10 (1) PD30/05 (6) PD33/08 (1) PD33/09 (6) PD34/05 (1) PD35/06 (6) PD36/10 (1) PD37/06 (6) PD37/08 (10) PD38/09 (3) PD41/05 (5) PD43/11 (1) PD47/09 (5)
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 |
