Metadata Report for BODC Series Reference Number 1761301
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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Parameters |
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Problem Reports
No Problem Report Found in the Database
OSMOSIS RRS James Cook JC090 navigation quality control report
Bathymetry
Channel was screened using GEBCO bathymetry as a guide. Several M flags were applied throughout the series where the depth was very noisy. Several N flags occur where there are drop outs.
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.
OSMOSIS RRS James Cook JC090 navigation instrumentation
Instrumentation
The following scientific navigation and bathymetry systems were fitted.
Manufacturer | Model | Function | Comments |
Applanix | POS MV | DGPS and attitude | Primary GPS |
Kongsberg Seatex | Seapath 200 | DGPS and attitude | Secondary GPS |
Kongsberg Seatex | DPS116 | Ship's DGPS | Bridge GPS |
Ashtech | ADU-5 | DGPS and attitude | - |
C-Nav | 3050 | DGPS and DGNSS | - |
Kongsberg Maritime | EA600 | Single beam echo sounder | Used in RVS files |
Kongsberg Maritime | EA500 | Single beam echo sounder | Used to track pingers, no data logged |
Kongsberg Maritime | EM120 | Deep water multi-beam echo sounder | - |
Kongsberg Maritime | EM710 | Shallow water multi-beam echo sounder | - |
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.
OSMOSIS RRS James Cook JC090 navigation data processing procedures
Originator's Data Processing
Navigation -
All GPS and attitude measurement systems were run throughout the cruise. The POSMV system is the vessel's primary GPS system, outputting the position of the ship's common reference point in the gravity meter room. The POSMV is the GPS that is repeated around the vessel and sent out to other systems.
Data was extracted from TECHSAS position-Applanix_GPS_JC1.gps data stream each day and concatenated into a single file in time order. Time was converted from TECHSAS days to seconds from time origin (1/1/2013 0:0:0). Variables were averaged into 30 second intervals and smoothed.
Bathymetry -
The Kongsberg EA600 12 kHz single beam echo sounder was run throughout the cruise. The EA600 was used with a constant sound velocity of 1500 ms-1 throughout the water column to allow it to be corrected for sound velocity in post processing. As well as depths being logged to the Techsas and Level-C data loggers, files were saved as .BMP images and in raw Kongsberg format.
Files delivered to BODC
Filename | Content description | Format | Interval | Start date/time (UTC) | End date/time (UTC) | Comments |
position_Applanix_GPS_JC1_gps | Best available position | Matlab | 30 seconds | 01/09/2013 00:00 | 14/09/2013 23:59 | - |
bestnav | Ship's heading | RVS | 1 second | 30/08/2013 10:00:00 | 16/09/2013 14:00:00 | - |
prodep | Echosounder bathymetry | RVS | 1 second | 01/09/2013 07:00:00 | 16/09/2013 07:00:00 | - |
BODC Data Processing
The files mentioned above were selected for data banking because they contained the best version of unprocessed position, heading and bathymetry. Data were banked at BODC following standard data banking procedures. The originator's variables were mapped to appropriate BODC parameter codes as follows:
posmvpos
Originator's variable | Originator's units | Description | BODC Code | BODC Units | Unit conversion | Comments |
lat | decimal degrees | Latitude north (WGS84) by unspecified GPS system | ALATGP01 | decimal degrees | - | - |
lon | decimal degrees | Longitude east (WGS84) by unspecified GPS system | ALONGP01 | decimal degrees | - | - |
The file also contained speed_made_good, course_made_good, distance_run, heading average, heading_average_corrected, ship_u, ship_v, however these parameters were not transferred as they were derived or could be extracted from a more accurate source.
gryopmv
Originator's variable | Originator's units | Description | BODC Code | BODC Units | Unit conversion | Comments |
heading | degrees true | Orientation (horizontal relative to true north)of measurement device {heading} | HEADCM01 | degrees true | - | - |
EA600
Originator's variable | Originator's units | Description | BODC Code | BODC Units | Unit conversion | Comments |
depth | m | Sea-floor depth (below instantaneous sea level){bathymetric depth} in the water body by echo sounder and correction using Carter's tablesdepth measured by echosounder | MBANCT01 | m | - | - |
Screening
All the reformatted data were visualised using the in-house EDSERPLO software. Suspect data were marked by adding an appropriate quality control flag.
Position
A check was run on positional data to identify gaps and improbable values (through the calculation of speed). No gaps or improbable values were identified.
Ship's velocities
Ship velocities were calculated from the main latitude and longitude channels using standard BODC procedures.
Distance Run
Distance run was calculated from the main latitude and longitude channels, starting from the beginning of the file, using BODC standard procedures.
Project Information
Ocean Surface Mixing, Ocean Sub-mesoscale Interaction Study (OSMOSIS)
Background
The Ocean Surface Mixing, Ocean Sub-mesoscale Interaction Study (OSMOSIS) consortium was funded to deliver NERC's Ocean Surface Boundary Layer (OSBL) programme. Commencing in 2011, this multiple year study will combine traditional observational techniques, such as moorings and CTDs, with the latest autonomous sampling technologies (including ocean gliders), capable of delivering near real-time scientific measurements through the water column.
The OSMOSIS consortium aims to improve understanding of the OSBL, the interface between the atmosphere and the deeper ocean. This layer of the water column is thought to play a pivotal role in global climate and the productivity of our oceans.
OSMOSIS involves collaborations between scientists at various universities (Reading, Oxford, Bangor, Southampton and East Anglia) together with researchers at the National Oceanography Centre (NOC), Scottish Association for Marine Science (SAMS) and Plymouth Marine Laboratory (PML). In addition, there are a number of project partners linked to the consortium.
Scientific Objectives
- The primary goal of the fieldwork component of OSMOSIS is to obtain a year-long time series of the properties of the OSBL and its controlling 3D physical processes. This is achieved with an array of moorings (two nested clusters of 4 moorings, each centred around a central mooring) and gliders deployed near the Porcupine Abyssal Plain (PAP) observatory. Data obtained from this campaign will help with the understanding of these processes and subsequent development of associated parameterisations.
- OSMOSIS will attempt to create parameterisations for the processes which determine the evolving stratification and potential vorticity budgets of the OSBL.
- The overall legacy of OSMOSIS will be to develop new (physically based and observationally supported) parameterisations of processes that deepen and shoal the OSBL, and to implement and evaluate these parameterisations in a state-of-the-art global coupled climate model, facilitating improved weather and climate predictions.
Fieldwork
Three cruises are directly associated with the OSMOSIS consortium. Preliminary exploratory work in the Clyde Sea (September 2011) to hone techniques and strategies, followed by a mooring deployment and recovery cruise in the vicinity of the Porcupine Abyssal Plain (PAP) observatory (in late Summer 2012 and 2013 respectively). Additional opportunist ship time being factored in to support the ambitious glider operations associated with OSMOSIS.
Instrumentation
Types of instrumentation and measurements associated with the OSMOSIS observational campaign:
- Ocean gliders
- Wave rider buoys
- Towed SeaSoar surveys
- Microshear measurements
- Moored current meters, conductivity-temperature sensors and ADCPs
- Traditional shipboard measurements (including CTD, underway, discrete nutrients, LADCP, ADCP).
Contacts
Collaborator | Organisation |
---|---|
Prof. Stephen Belcher | University of Reading, U.K |
Dr. Alberto C Naveira Garabato | University of Southampton, U.K |
Data Activity or Cruise Information
Cruise
Cruise Name | JC090 |
Departure Date | 2013-08-31 |
Arrival Date | 2013-09-16 |
Principal Scientist(s) | Alberto C Naveira Garabato (University of Southampton School of Ocean and Earth Science) |
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 |