Metadata Report for BODC Series Reference Number 1759726
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
UK Ocean Acidification RRS James Cook Cruise JC073 Underway Navigation and Bathymetry Data Quality Report
Navigation
The navigation data were checked for gaps and improbable ship speeds. There were six gaps of short duration, which were filled by linear interpolation. These values have been flagged to indicate that they are interpolated.
Bathymetry
The bathymetric data were screened with reference to GEBCO atlas bathymetry. The depth channel is rather intermittent, and a few spikes have been flagged as suspect.
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.
Ashtech Global Positioning System receivers (ADU series)
The ADU series of Global Positioning System (GPS) receivers are designed to give real-time three-dimensional position and attitude measurements. Attitude determination is based on differential carrier phase measurements between four antennas connected to a receiver, providing heading, pitch and roll, along with three-dimensional position and velocity.
The ADU2 model receives information from 48 channels, while the upgraded model (ADU5) uses 56 channels. The ADU5 also features a unique Kalman filter with user selectable dynamic modes to match operating conditions. It also incorporates signals from Satellite Based Augmentation Systems (SBAS) and features an embedded 2-channel 300 kHz beacon receiver for easy differential GPS (DGPS) operations.
Specifications
| Parameter | ADU2 | ADU5 |
| Operational Temperature range: | | |
| Sampling frequency | 5 Hz | 5 Hz |
| Receiver channels | 48 | 56 |
| Accuracy: | | |
| Circular Error Probability: | | |
Further details can be found in the manufacturer's specification sheets for the ADU2 andADU5.
Kongsberg Seatex Seapath 200 GPS and Gyrocompass
The Seapath 200 is a highly accurate, real-time heading, attitude and position information system that integrates the best signal characteristics of Inertial Measurement Units (IMU) and Global Positioning System (GPS), using a differential GPS method to acquire this data.
The high-rate motion data is obtained from the Seatex MRU5 inertial sensor and two fixed baseline GPS carrier-phase receivers. The raw data is integrated in a Kalman filter in the Seapath Processing Unit. The IMU contains an accurate linear accelerometer and Bosch Coriolis force angular rate gyros (CFG).
This system is equipped to utilise up to six different DGPS reference stations, it checks for consistency within measurements from the different sensors to ensure reliability and rejects noisy data or reports its inaccuracy. The data is available through various output protocols, RS-232, RS-422 and Ethernet.
This instrument is no longer in production; the main characteristics are presented below, and the specification sheet can be accessed here Kongsberg Seatex Seapath 200 .
Specifications
| Scale factor error in pitch, roll and heading | 0.2% RMS |
| Heave motion periods | 1 to 25 s |
| Accuracy | |
| Heading | 0.05° RMS (4 m baseline) 0.075° RMS (2.5 m baseline) |
| Roll and Pitch | 0.03° EMS (± 5° amplitude) |
| Heave | 5 cm or 5%, whichever is highest |
| Position | 0.7 RMS or 1.5 m (95% CEP) with DGPS 0.15 m EMS or 0.4 m (95% CEP) with Searef 100 corrections |
| Velocity | 0.03 m s-1 RMS or 0.07 m s-1 (95% CEP) with DGPS |
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.
UK Ocean Acidification RRS James Cook Cruise JC073 Underway Navigation and Bathymetry Instrumentation
The instruments used to collect the navigation and bathymetry datasets are displayed in the table below.
| Instrument | Type |
|---|---|
| Applanix POS MV 320 | GPS |
| Seapath DPS200 | GPS |
| Ashtech ADU5 | GPS |
| Sperry Marine Gyrocompass | Gyro compass |
| Kongsberg EA600 Precision Echo Sounder | Echosounder |
UK Ocean Acidification RRS James Cook Cruise JC073 Underway Navigation Data Processing 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. 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 calculates the ship's relative motion. It uses the ship's gyro compass and Chernikeef Log data to determine movement in a given direction. This may be used by bestnav to calculate fixes in case GPS fixes are not available.
- BESTNAV takes all GPS Systems to compile the best possible account of the ship's track. If the primary GPS stream is continuous, it just takes that. Gaps are filled from the secondary GPS or, if necessary, tertiary GPS. If all GPS streams fail, BESTNAV can fill gaps using RELMOV and dead reckoning.
- BESTDRF calculates northward and eastward drift velocity vn and ve from BESTNAV latitude and longitude.
- PRODEP applies Carter's corrections to the echo sounder data, based on the latitude/longitude position of the measurement.
BODC Data Processing
Reformatting
The underway data were reformatted from the originator's ASCII format to BODC's in-house standard. All parameters were merged into a single file, with a common time channel. Data supplied at higher frequency than the BODC file were bin-averaged to the appropriate time-interval. Directional data were averaged over a unit circle.
The following navigation and bathymetry parameters were transferred to the BODC underway file:
| bestnav | |||||
|---|---|---|---|---|---|
| Channels | Description | Units | BODC Parameter Code | Units | Conversion Factor |
| lat | Latitude | Degrees +ve N | ALATGP01 | Degrees +ve N | - |
| lon | Longitude | Degrees +ve E | ALONGP01 | Degrees +ve E | - |
| heading | Ship's heading | Degrees True | HEADCM01 | Degrees True | - |
| depth | Raw depth from echosounder | m | MBANUA01 | m | - |
Screening
Each data channel was inspected on a graphics workstation and any spikes or periods of dubious data were flagged. The power of the workstation software was used to carry out comparative screening checks between channels by overlaying data channels. A map of the cruise track was simultaneously displayed in order to take account of the oceanographic context.
Data Processing
Navigation
BODC recalculated diagnostic parameters: distance run (DSRNCV01), and northward (APNSGP01)and eastward (APEWGP01) components of velocity. The navigation data were checked for gaps and improbable speeds. A few short gaps (two of about ten minutes duration, and four of one minute duration) were identified, and filled by linear interpolation from neighbouring values. There were no speed check failures.
Bathymetry
Corrected bathymetric data were not supplied to BODC. BODC transferred the uncorrected bathymetry to the underway file, and then applied Carter's corrections generating channel MBANCT01.
Calibration
No field or manufacture calibrations were applied to the navigation and bathymetry data at BODC.
Project Information
UKOARP Theme B: Ocean acidification impacts on sea surface biology, biogeochemistry and climate
The overall aim of this theme is to obtain a quantitative understanding of the impact of ocean acidification (OA) on the surface ocean biology and ecosystem and on the role of the surface ocean within the overall Earth System.
The aims of the theme are:
- To ascertain the impact of OA on planktonic organisms (in terms of physiological impacts, morphology, population abundances and community composition).
- To quantify the impacts of OA on biogeochemical processes affecting the ocean carbon cycle (both directly and indirectly, such as via availability of bio-limiting nutrients).
- To quantify the impacts of OA on the air-sea flux of climate active gases (DMS and N2O in particular).
The main consortium activities will consist of in-situ measurements on three dedicated cruises, as well as on-deck bioassay experiments probing the response of the in-situ community to elevated CO2. Most of the planned work will be carried out on the three cruises to locations with strong gradients in seawater carbon chemistry and pH; the Arctic Ocean, around the British Isles and the Southern Ocean.
Weblink: http://www.oceanacidification.org.uk/research_programme/surface_ocean.aspx
Data Activity or Cruise Information
Cruise
| Cruise Name | JC073 |
| Departure Date | 2012-05-18 |
| Arrival Date | 2012-06-15 |
| Principal Scientist(s) | John Murray Roberts (Heriot Watt University School of Life Sciences) |
| 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 |
