Metadata Report for BODC Series Reference Number 1762261
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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Problem Reports
No Problem Report Found in the Database
AMT RRS James Cook Cruise JC079 AMT22 Navigation and Bathymetry Data Quality Document
The navigation data have been through BODC quality control screening. The 15 gaps of less than ten minutes have been filled by interpolation. Overall the data for the cruise duration appear good.
The bathymetric data have been through BODC quality control screening. There are periods of noise that hide the real bathymetry in the channel. Where possible some periods have been flagged to remove the noise. Users should use caution when interpreting the bathymetric depth channel.
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
Kongsberg EA600 Single Beam Echosounder
The EA600 is a single beam echosounder with full ocean depth capability designed for bathymetric surveys. It measures water depth by monitoring the travel time of an acoustic signal that is transmitted from the ship, reflected off the seabed and received back at the ship.
The main components of the system are hull-mounted transducers linked to general purpose transceivers (GPTs). Up to four GPTs, each controlling one or more transducers, may be operated simultaneously. The GPT generates a signal, which is transmitted into the water column as an acoustic pulse by the transducer array, and the returning echo is recorded by the GPT. GPTs are in turn linked to a combined display and processor, where adjustments (such as sound-speed corrections) may be applied to the data. Available frequencies span from 12 to 710 kHz, and each GPT may operate at a separate frequency. A variety of transducers is available for water depths up to 11,000 m.
The EA600 stores all data internally but has a USB port which allows the possibility of connecting a CD-ROM/DVD drive to read and write the data. All echo data can be stored as files: bitmap, sample, depth or sidescan data.
In deeper waters, the EA600 supports a multipulse function, allowing for a higher pinger rate. While on passive mode, the pinger is normally attached to a device, with the purpose of tracking and displaying its current depth.
The EA600 replaced the EA500 in 2000.
Specifications
| Maximum Ping rate | 20 Hz |
| Resolution | 1 cm |
| Accuracy | 1 cm at 710 and 200 kHz |
| Operating frequencies | 1 or 2 kHz |
| Single Beam frequencies | 12, 18, 33, 38, 50, 70, |
| Dynamic range | 160 dB |
Further details can be found in the manufacturer's specification sheet.
AMT RRS James Cook Cruise JC079 AMT22 Navigation and Bathymetry Instrument Description Document
| Sensor | Serial number | Last calibration date | Deployment |
| Gill Wind sonic (Option 3) | 064537 | - | Starboard |
| Skye Instruments SKE510 | 28560 | 2011-07-05 | Starboard |
| Skye Instruments SKE510 | 28561 | 2011-07-11 | Port |
| Kipp and Zonen Ltd CMB6 | 973134 | 2011-07-15 | Starboard |
| Kipp and Zonen Ltd CMB6 | 973135 | 2011-07-15 | Port |
| Vaisala PTB100A | U1420016 | 2012-03-26 | Starboard |
| Vaisala HMP45A | E1055002 | 2012-07-02 | Starboard |
Kongsberg Seatex Differential Positioning Sensor 116
A 14-channel, all-in-view, L1 GPS receiver which primarily utilises the free, WAAS, EGNOS and MSAS Satellite Based Augmentation Systems (SBAS) for differential corrections (DGPS). It is also capable of simultaneous DGPS from a wide variety of other reference stations (Multiref), resulting in improved accuracy. Simultaneous reception and use of correction signals in MF and UHF frequency bands, Inmarsat standard A, B and M terminals and SeaSTAR Spot, are possible.
| Performance | |
| DGPS position accuracy with SBAS service | < 1.5 m, 95% CEP (*) 0.6 m, 1θ (*) |
| DGPS position accuracy (Multiref) | < 1 m, 95% CEP (**) 0.4 m, 1θ (**) |
| Velocity accuracy | 0.05 m/s, 95% CEP (**) 0.02 m/s, 1θ (**) |
| Output rate | 1 Hz |
(*) Accuracy specifications are based on real-life tests conducted using WAAS and an open view to the sky in Houston, Texas.
(**) Accuracy specifications are based on real-life tests conducted under low multipath conditions and an open view to the sky in Trondheim, Norway. Tests at different locations under different conditions may produce different results.
Full specifications can be found here.
Sperry Marine NAVIGAT X MK 1 digital gyrocompass
A digital gyrocompass for use in marine navigation. The system comprises a gyrosphere supported in fluid, suspended at a single point. The centering pin retaining arrangement can be mounted in an additional gimbal system for high speed applications (Mod 7). The system can drive up to 12 analogue repeaters and has 7 independent serial outputs and 2 dependent 6 steps/° heading outputs. The NAVIGAT X MK1 was the first of the Sperry Marine range of heading sensors, which comprises the NAVIGAT 3000 fibreoptic gyrocompass, the NAVIGAT X MK 1 and the NAVIGAT X MK 2 digital gyrocompasses.
Specifications
| Heading accuracy | <0.1° secant latitude (linear mean settle point error) <0.1° secant latitude (static) <0.4° secant latitude (dynamic) |
| Freedom of pitch and roll | ±40° (Mod 10) ±90° (Mod 7) |
Detailed specifications can be found in the manufacturer's data sheet.
Trimble Applanix Position and Orientation Systems for Marine Vessels (POSMV)
The Position and Orientation Systems for Marine Vessels (POSMV) is a real time kinematic (RTK) and differential global positioning system (DGPS) receiver for marine navigation. It includes an inertial system that provides platform attitude information. The instrument provides accurate location, heading, velocity, attitude, heave, acceleration and angular rate measurements.
There are three models of Applanix POSMV, the POS MV 320, POS MV Elite and the POS MV WaveMaster. POS MV 320 and POS MV WaveMaster are designed for use with multibeam sonar systems, enabling adherence to IHO (International Hydrographic Survey) standards on sonar swath widths of greater than ± 75 degrees under all dynamic conditions. The POS MV Elite offers true heading accuracy without the need for dual GPS installation and has the highest degree of accuracy in motion measurement for marine applications.
Specifications
POS MV 320
| Componenet | DGPS | RTK | GPS Outage |
|---|---|---|---|
| Position | 0.5 - 2 m 1 | 0.02 - 0.10 m 1 | <2.5 m for 30 seconds outages, <6 m for 60 seconds outages |
| Roll and Pitch | 0.020° | 0.010° | 0.020° |
| True Heading | 0.020° with 2 m baseline 0.010° with 4 m baseline | - | Drift <1° per hour (negligible for outages <60 seconds) |
| Heave | 5 cm or 5% 2 | 5 cm or 5% 2 | 5 cm or 5% 2 |
POS MV WaveMaster
| Accuracy | DGPS | RTK | GPS Outage |
|---|---|---|---|
| Position | 0.5 - 2 m 1 | 0.02 - 0.10 m 1 | <3 m for 30 seconds outages, <10 m for 60 seconds outages |
| Roll and Pitch | 0.030° | 0.020° | 0.040° |
| True Heading | 0.030° with 2 m baseline | - | Drift <2° per hour |
| Heave | 5 cm or 5% 2 | 5 cm or 5% 2 | 5 cm or 5% 2 |
POS MV Elite
| Accuracy | DGPS | RTK | GPS Outage |
|---|---|---|---|
| Position | 0.5 - 2 m 1 | 0.02 - 0.10 m 1 | <1.5 m for 60 seconds outages DGPS, <0.5 m for 60 seconds outage RTK |
| Roll and Pitch | 0.005° | 0.005° | 0.005° |
| True Heading | 0.025° | 0.025° | Drift <0.1° per hour (negligible for outages <60 seconds) |
| Heave | 3.5 cm or 3.5% 2 | 3.5 cm or 3.5% 2 | 3.5 cm or 3.5% 2 |
1 One Sigma, depending on quality of differential corrections
2 Whichever is greater, for periods of 20 seconds or less
Further details can be found in the manufacturer's specification sheet.
AMT RRS James Cook Cruise JC079 AMT22 Navigation and Bathymetry Processing Procedures Document
Originator's Data Processing
During the cruise there was a dual logging system in place on the RRS James Cook. Data from the various instruments were logged to the RVS Level-C system and also as NetCDF (binary) through the Ifremer Techsas data logging system. The following instruments were logged during the cruise:
1) Applanix POS MV DGPS (logged to RVS format as posmvpos)
2) C-Nav 300 DGPS (logged to RVS format as gps_cnav)
3) Kongsberg Seatex DPS116 DGPS (logged to RVS format as dps116)
4) Chernikeef EM speed log (logged to RVS format as log_chf)
5) Ship's Gyrocompass (logged to RVS format as gyro_s)
6) Simrad EA600 Precision Echo Sounder (logged to RVS format as ea600m)
Processing was carried out using the RVS software suite. The following routines were run on the navigation and bathymetry data channels to produce files named after the routine that generated them:
RELMOV - Relmov is the relative motion file for this cruise. This was generated using the ships gyro and ships Chernikeef Log data to extract a movement in a given direction. This was then used by bestnav when and where necessary to calculate fixes if GPS fixes were not available.
BESTNAV - Bestnav uses all 3 GPS Systems logged and creates a best suite stream by providing an as complete account of the ships track as possible. This is done by reading all 3 GPS streams with posmvpos being primary, gps_cnav as secondary and dps116 as tertiary. The system looks for gaps of a certain length in the primary and when it finds those gaps it requests that the next gps down fill in the gaps. If no GPS data is available it asks RELMOV to fill in until data is available again. Then the system calculates back over itself to ensure that the extrapolated positions are correct using the GPS data available around the gap.
BESTDRF - Bestdrf is a product of bestnav. When run bestnav uses the relmov data which contains a predicted vn and ve based upon direction and speed through the water. The Bestdrf file is the accurate drift velocity of what actually occurred based on the GPS changes between each record.
PRODEP - Prodep is an automated process that accessed the bestnav position fix data and then uses a pre programmed Carter tables of corrections and corrects the echo sounder data for that given time.
The data from the BESTNAV and PRODEP routines were taken for transfer into the underway dataset.
| Filename | Data type | Start Calendar Day | Start Time | Finish Calendar Day | Finish Time | Data Interval |
| bestnav | RVS Level-C processed | 2012-10-10 | 08:00:00 | 2012-11-20 | 20:00:40 | 10 seconds |
| prodep | RVS Level-C processed | 2012-10-10 | 09:05:15 | 2012-11-20 | 20:00:05 | variable |
BODC Data Processing
The RVS Level-C files were chosen for transfer to the BODC underway file.
The bestnav and prodep data were transferred. A description of the channels present in the files, units, whether they were transferred, BODC parameter code and units, and if a unit conversion was applied during the transfer are detailed in the table below:
| bestnav | Channels | Description | Units | BODC Parameter Code | Units | Conversion Factor |
| lat | Latitude | Degrees +ve N | ALATGP01 | Degrees +ve N | *1 | |
| lon | Longitude | Degrees +ve E | ALONGP01 | Degrees +ve E | *1 | |
| vn | Northwards velocity | knots | APNSGP01 | cm s-1 | *51.44 | |
| ve | Eastwards velocity | knots | APEWGP01 | cm s-1 | *51.44 | |
| cmg | Course made good | Degrees True | APDAGP01 | Degrees True | *1 | |
| smg | Speed made good | knots | APSAGP01 | m s-1 | *0.514 | |
| dist_run | Distance run | Nautical mile | DSRNCV01 | km | *1.852 | |
| heading | Ship's heading | Degrees True | HEADCM01 | Degrees True | *1 | |
| prodep | Channels | Description | Units | BODC Parameter Code | Units | Conversion Factor |
| uncdepth | Raw depth from echosounder | m | MBANZZ01 - To be dropped after screening | m | *1 | |
| cordepth | Depth corrected from Carter's tables | m | MBANCT01 | m | *1 | |
| cartarea | Carter's table area from position | - | not for transfer | - | - |
The navigation channels were checked using BODC Matlab routine 'navcheck' and 15 gaps were identified. Each period was less than 10 minutes in duration and using the BODC Matlab routine 'navint' the gaps were filled by interpolation. There were no speed check failures.
Sample Calibrations
No calibrations were applied to these data by BODC.
Project Information
Oceans 2025 Theme 10, Sustained Observation Activity 1: The Atlantic Meridional Transect (AMT)
The Atlantic Meridional Transect has been operational since 1995 and through the Oceans 2025 programme secures funding for a further five cruises during the period 2007-2012. The AMT programme began in 1995 utilising the passage of the RRS James Clark Ross between the UK and the Falkland Islands southwards in September and northwards in April each year. Prior to Oceans 2025 the AMT programme has completed 18 cruises following this transect in the Atlantic Ocean. This sustained observing system aims to provide basin-scale understanding of the distribution of planktonic communities, their nutrient turnover and biogenic export in the context of hydrographic and biogeochemical provinces of the North and South Atlantic Oceans.
The Atlantic Meridional Transect Programme is an open ocean in situ observing system that will:
- give early warning of any fundamental change in Atlantic ecosystem functionng
- improve forecasts of the future ocean state and associated socio-economic impacts
- provide a "contextual" logistical and scientific infrastructure for independently-funded national and international open ocean biogeochemical and ecological research.
The specific objectives are:
- To collect hydrographic, chemical, ecological and optical data on transects between the UK and the Falkland Islands
- To quantify the nature and causes of ecological and biogeochemical variability in planktonic ecosystems
- To assess the effects of variability in planktonic ecosystems on biogenic export and on air-sea exchange of radiatively active gases
The measurements taken and experiments carried out on the AMT cruises will be closely linked to Themes 2 and 5. The planned cruise track also allows for the AMT data to be used in providing spatial context to the Sustained Observation Activities at the Porcupine Abyssal Plain Ocean Observatory (SO2) and the Western Channel Observatory (SO10).
More detailed information on this Work Package is available at pages 6 - 9 of the official Oceans 2025 Theme 10 document: Oceans 2025 Theme 10
Weblink: http://www.oceans2025.org/
Data Activity or Cruise Information
Cruise
| Cruise Name | JC079 (AMT22) |
| Departure Date | 2012-10-10 |
| Arrival Date | 2012-11-24 |
| Principal Scientist(s) | Glen A Tarran (Plymouth Marine Laboratory) |
| Ship | RRS James Cook |
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 |
|---|---|
| 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 |
