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Metadata Report for BODC Series Reference Number 1761301


Metadata Summary

Data Description

Data Category Bathymetry
Instrument Type
NameCategories
Kongsberg (Simrad) EA600 Echosounder  single-beam echosounders
Trimble Applanix POSMV global positioning system  Differential Global Positioning System receivers; inertial navigation systems; Kinematic Global Positioning System receivers
Instrument Mounting research vessel
Originating Country United Kingdom
Originator Dr Alex Forryan
Originating Organization National Oceanography Centre, Southampton
Processing Status banked
Online delivery of data Download available - Ocean Data View (ODV) format
Project(s) OSMOSIS
 

Data Identifiers

Originator's Identifier JC090_PRODQXF_NAV
BODC Series Reference 1761301
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2013-09-01 00:00
End Time (yyyy-mm-dd hh:mm) 2013-09-14 23:59
Nominal Cycle Interval 30.0 seconds
 

Spatial Co-ordinates

Southernmost Latitude 42.60383 N ( 42° 36.2' N )
Northernmost Latitude 49.00200 N ( 49° 0.1' N )
Westernmost Longitude 16.35967 W ( 16° 21.6' W )
Easternmost Longitude 10.33417 W ( 10° 20.1' W )
Positional Uncertainty 0.0 to 0.01 n.miles
Minimum Sensor or Sampling Depth -
Maximum Sensor or Sampling Depth -
Minimum Sensor or Sampling Height -
Maximum Sensor or Sampling Height -
Sea Floor Depth -
Sea Floor Depth Source -
Sensor or Sampling Distribution -
Sensor or Sampling Depth Datum -
Sea Floor Depth Datum -
 

Parameters

BODC CODERankUnitsTitle
AADYAA011DaysDate (time from 00:00 01/01/1760 to 00:00 UT on day)
AAFDZZ011DaysTime (time between 00:00 UT and timestamp)
ALATGP011DegreesLatitude north relative to WGS84 by unspecified GPS system
ALONGP011DegreesLongitude east relative to WGS84 by unspecified GPS system
APEWGP011Centimetres per secondEastward velocity of measurement platform relative to ground surface by unspecified GPS system
APNSGP011Centimetres per secondNorthward velocity of measurement platform relative to ground surface by unspecified GPS system
DSRNCV011KilometresDistance travelled
HEADCM011DegreesOrientation (horizontal relative to true north) of measurement device {heading}
MBANCT011MetresSea-floor depth (below instantaneous sea level) {bathymetric depth} in the water body by echo sounder and correction using Carter's tables

Definition of Rank

  • Rank 1 is a one-dimensional parameter
  • Rank 2 is a two-dimensional parameter
  • Rank 0 is a one-dimensional parameter describing the second dimension of a two-dimensional parameter (e.g. bin depths for moored ADCP data)

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
2 cm at 120 kHZ
5 cm at 38 kHz
10 cm at 18 kHz
20 cm at 12kHz

Operating frequencies 1 or 2 kHz
Single Beam frequencies

12, 18, 33, 38, 50, 70,
120, 200, 210 or 710 kHz

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
Q value below limit of quantification