Metadata Report for BODC Series Reference Number 2309274
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
RRS James Cook Cruise JC062 Underway navigation: Data Quality Report
ASHTECH heading experienced a large drop out between 18/08/2011 18:02:38 - 22/08/2011 05:35:38. The data were flagged appropriately. (BODC assessment)
RRS James Cook Cruise JC062 Underway navigation: Problem Report
The echo sounder channel was very noisy, indicating that the sensor settings were not frequently monitored. Despite this, bottom returns could be easily observed within the spiky portions of data. Spikes in the data were flagged appropriately. Data should be used with caution. (BODC assessment)
Data Access Policy
Open 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.
If the Information Provider does not provide a specific attribution statement, or if you are using Information from several Information Providers and multiple attributions are not practical in your product or application, you may consider using the following:
"Contains public sector information licensed under the Open Government Licence v1.0."
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.
Kongsberg EM120 Multibeam Echosounder
The EM120 is a low frequency (12 kHz) multibeam 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 system units of the EM120 are transducer arrays (separate for reception and transmission), preamplifier unit, transceiver unit and operator unit. Sub-bottom profiling capability is an optional extra. For both transmit and receive arrays standard beamwidth is 1° or 2°, and 4° beamwidth is available for the receive array.
The system has 191 beams with pointing angles automatically adjusted according to achievable coverage or operator defined limits. The beam spacing is normally equidistant, corresponding to 1% of depth at 90° angular coverage, 2% at 120° and 3% at 140°. The transmit fan is split into several individual sectors, each of which is corrected independently for vessel roll, pitch and yaw, which places all soundings on a "best fit" to a line perpendicular to the survey line.
The EM120 supersedes the EM12 and was itself superseded by the EM122 in 2008.
Specifications
| Frequency | 12 kHz |
| Maximum ping rate | 5 Hz |
| Range sampling rate | 2 kHz |
| Swath coverage sector | up to 150° |
| Swath width | up to 5.5 x water depth |
| Depth resolution | 10 to 40 cm |
| Depth range | 20 to 11,000 m |
| Pulse length | 2, 5 and 15 ms |
| Number of beams | 191 |
| Beam width | 1° x 1° |
| Beam spacing (at angular coverage) | 1% of depth at 90° |
Further details can be found in the manufacturer's specification 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.
RRS James Cook Cruise JC062 Underway navigation: Instrumentation
The following scientific navigational and bathymetric systems were fitted.
| Instrument | Type | Code | Main Role |
| Navigation | Ashtech ADU-5 | - | DGPS and attitude |
| Navigation | Kongsberg Seatex DPS116 | - | Ship's DGPS |
| Navigation | Kongsberg Seatex Seapath DPS200 | - | Swath DGPS and attitude |
| Navigation | C-Nav 3050 | - | DGPS and DGNSS |
| Navigation and gyrocompasses | Applanix POS MV | - | DGPS and attitude |
| Gyrocompasses | Sperry Marine | - | Heading |
| Speed log | Chernikeef Aquaprobe Mk5 Electromagnetic Log | - | Ship velocity |
| Echo sounding | Kongsberg Maritime Simrad 12Hz EA600 | - | Single-beam bathymetry |
| Echo sounding | Kongsberg Maritime Simrad EM120 | - | Swath (multibeam) bathymetry |
Single beam echo soundings are derived from either a drop keel-mounted (port) or towed sensor.
RRS James Cook Cruise JC062 Underway navigation: BODC processing
Data were banked at BODC following standard banking procedures. Data were averaged to 30 second intervals.
The originator's variables were mapped to appropriate BODC parameter codes as follows:
| Parameter | Units | Parameter code | Comments |
|---|---|---|---|
| Latitude | Degrees (+ve N) | ALATCN01 | - |
| Longitude | Degrees (+ve E) | ALONCN01 | - |
| Ship's heading (Gyro) | degrees | HEADCM01 | - |
| Ship's heading (GPS) | degrees | HDNGGP01 | Ashtech |
| Ship's eastward velocity | cm s-1 | APEWZZ01 | - |
| Ship's northward velocity | cm s-1 | APNSZZ01 | - |
| Distance run | km | DSRNCV01 | - |
| Course made good | Degrees | APDAZZ01 | - |
| Speed made good | m s-1 | APSAZZ01 | - |
| Bathymetric depth | m | MBANZZ01 | - |
| Bathymetric depth (GEBCO) | m | MBANGB08 | - |
All the reformatted data were visualised using the in-house EDSERPLO software. Suspect data were marked by adding an appropriate quality control flag.
Position
The following gaps and improbable values (identified by improbable ship speeds) were observed in the latitude and longitude channels:
| Gap 1 Start: 2011/08/29 11:15:08 End: 2011/08/29 11:34:38 Duration: 20 minutes | ||||||||||||||||||||||||||||||||||||||||
Small gaps (<30 mins) were interpolated. The file was then trimmed to span the length of the cruise (24/07/2011 to 29/08/2011).
Distance Run
Distance run was calculated from the main latitude and longitude channels, starting from the beginning of the day the cruise departed port (24/07/2011).
Ship's Velocities
The ship's velocities were calculated from the main latitude and longitude channels.
Bathymetry
Zeroes (drop-outs) were removed from bathymetry data.
Project Information
Oceans 2025 Theme 10, Sustained Observation Activity 2: Porcupine Abyssal Plain Ocean Observatory
The NERC Delivery Plan (2005) gives priority to developing ocean observing systems to detect climate change and its impact on ecosystems. One of the most effective ways to achieve this is by fixed point time-series eulerian observatories equipped with a diverse array of physical, biological and biogeochemical sensors. The Porcupine Abyssal Plain (PAP) observatory, involving high frequency measurements of both water column and seafloor processes, is the only UK open ocean observatory which meets these criteria. The PAP site has been monitored through a variety of projects since 1989. The National Oceanography Centre, Southampton (NOCS) will manage all monitoring activities at the PAP site for Oceans 2025. Spatial context to Sustained Observation Activity (SO) 2 will be provided by the Atlantic Meridional Transects (AMT) in SO 1 and by a Continuous Plankton Recorder (CPR) route (SO 15) which pass nearby.
More detailed information on this Work Package is available at pages 9 - 11 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 | JC062 |
| Departure Date | 2011-07-24 |
| Arrival Date | 2011-08-29 |
| Principal Scientist(s) | Henry Ruhl (National Oceanography Centre, Southampton) |
| 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 |
