Metadata Report for BODC Series Reference Number 2023018
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 Discovery cruise DY112 navigation quality control report
Bathymetry
The swath bathymetry did not produce readings until the approximately the 18/01/2020 20:00:00.
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 EM122 12kHz Multibeam Echosounder
The EM122 is designed to perform seabed mapping to full ocean depth with a high resolution, coverage and accuracy. Beam focusing is applied both during reception and transmission. The system has up to 288 beams/432 soundings per swath with pointing angles, which are automatically adjusted according to achievable coverage or operator defined limits.
This model uses both Continuous Wave and Frequency Modulated sweep pulses with pulse compression on reception, in order to increase the maximum useful swath width. The transmit fan is split in several individual sectors, with independent active steering, in order to compensate for the vessel movements.
In multiplying mode, two swaths per ping cycle are generated, with up to 864 soundings. The beam spacing is equidistant or equiangular and the transmit fan is duplicated and transmitted with a small difference in along track tilt, which takes into account depth coverage and vessel speed, to give a constant sounding separation along track. In high density mode, more than one sounding per beam can be produced, such that horizontal resolution is increased and is almost constant over the whole swath.
The EM122 transducers are modular linear arrays in a Mills cross configuration with separate units for transmit and receive. If used to deliver sub-bottom profiling capabilities with a very narrow beamwidth, this system is known as SBP120 Sub-Bottom Profiler.
The specification sheet can be accessed here Kongsberg EM122.
Specifications
Operational frequency | 12 Hz |
Depth range | 20 to 11000 m |
Swath width | 6 x depth, to approximately 30 km |
Pulse forms | Continuous Wave and Frequency Modulated chirp |
Swath profiles per ping | 1 or 2 |
Sounding pattern | equidistant on bottom/equiangular |
Depth resolution of soundings | 1 cm |
Sidelobe suppression | -25 dB |
Suppression of sounding artefacts | 9 frequency coded transmit sectors |
Beam focusing | On transmit (per sector) and on reception (dynamic) |
Swath width control | manual or automatic, all soundings intact even with reduced swath width |
Motion compensation | |
Yaw | ± 10° |
Pitch | ± 10° |
Roll | ± 15° |
EM122 versions
System version | 0.5x1 | 1x1 | 1x2 | 2x2 | 2x4 | 4x4 |
Transmit array (°) | 150x0.5 | 150x1 | 150x1 | 150x2 | 150x2 | 150x4 |
Receive array (°) | 1x30 | 1x30 | 2x30 | 2x30 | 4x30 | 4x30 |
No of beams/swath | 288 | 288 | 288 | 288 | 144 | 144 |
Max no of soundings/swath | 432 | 432 | 432 | 432 | 216 | 216 |
Max no of swaths/ping | 2 | 2 | 2 | 1 | 1 | 1 |
Max no of soundings/ping | 864 | 864 | 864 | 432 | 216 | 216 |
RRS Discovery cruise DY112 navigation instrumentation
Instrumentation
Make/model | Serial number | Last calibration date | Orientation | Status | Comments |
---|---|---|---|---|---|
Applanix POS MV 320 V5 | Primary scientific GPS and heading | ||||
Kongsberg Maritime EM122 | Corrected with Sound Velocity Probes | ||||
Kongsberg Maritime EA640 | Constant sound velocity of 1500 ms-1 |
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 Discovery cruise DY112 navigation data processing procedures
Originator's Data Processing
The data were logged by the TECHSAS (TECHnical and Scientific sensors Acquisition System) system into daily NetCDF files. The TECHSAS system is used as the main data logging system on NMF-SS operated reserach vessels. The daily TECHSAS NetCDF navigation and bathymetry files provided to BODC were used for BODC processing. Data were additionally logged into the RVS Level-C format files which have been archived at BODC.
Files delivered to BODC
Filename | Function | Format | Resolution | Start time | End time | Comments |
---|---|---|---|---|---|---|
*-position-Applanix_GPS_*.gps | Position, COG, SOG | TECHSAS | 1 Hz | 14-Jan-2020 14:59:33 | 24-Jan-2020 22:01:32 | |
*-gyro-GYRO1_*.gyr | Heading | TECHSAS | 1 Hz | 14-Jan-2020 14:59:33 | 24-Jan-2020 22:01:32 | |
*-sb_depth-EM120_*.depth | Sea-floor depth swath | TECHSAS | 1 Hz | 14-Jan-2020 14:59:33 | 23-Jan-2020 00:35:59 | Data starts 18/01/2020 20:01:23 |
*-EA600-*.EA600 | Sea-floor depth | TECHSAS | 1 Hz | 14-Jan-2020 14:59:33 | 24-Jan-2020 22:01:31 | Data starts 16/01/2020 09:23:17 |
BODC Data Processing
The data were reformatted to BODC internal format using standard banking procedures. Data were averaged at 60 second intervals. The following table shows how variables within the file were mapped to appropriate BODC parameter codes:
Source file | Originator's variable | Units | Description | BODC code | BODC unit | Converion | Comments |
---|---|---|---|---|---|---|---|
*-position-Applanix_GPS_*.gps | lat | degrees_north | Latitude | ALATGP01 | degrees_north | ||
*-position-Applanix_GPS_*.gps | long | degrees_east | Longitude | ALONGP01 | degrees_east | ||
*-position-Applanix_GPS_*.gps | gndspeed | knots | Speed over ground (SOG) | APSAGP01 | m/s | *0.51444444 | |
*-position-Applanix_GPS_*.gps | gndcourse | degrees T | Course over ground (COG) | APDAGP01 | degrees T | ||
*-gyro-GYRO1_*.gyr | heading | degrees T | Heading | HEADCM01 | degrees T | ||
*-sb_depth-EM120_*.depth | snd | m | Sea floor depth | MBANSWCB | m | ||
*-EA600-*.EA600 | depthm | m | Sea floor depth | MBANZZ01 | m | Dropped (swath superior) | |
GEBCO (15 min) bathymetry | MBANGB19 | m | Derived at BODC |
Processing
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 where speed is >10 m/s). No issues were detected.
GEBCO
GEBCO bathymetry (15 second grid) was added to the file using the main latitude and longitude channels. It was used to screen echo-sounder bathymetry.
Distance Run
Distance run was calculated from the main latitude and longitude channels, starting from the beginning of the file, using BODC standard procedures.
Bathymetry
The multi-beam echo-sounder was considered the best source of sea floor depth as single-beam echo-sounder contained high noise. Swath bathymetry data were filtered of noise twice by applying a moving median window of 30 secs and removing all data outside 3 standard deviations followed by applying a moving average window of 20 secs and removing all data outside 1 standard deviations.
Project Information
Carbon Uptake and Seasonal Traits of Antarctic Remineralisation Depth (CUSTARD)
Carbon Uptake and Seasonal Traits of Antarctic Remineralisation Depth (CUSTARD) is a £1.8 million, four-year (2018-2022) research project funded by the Natural Environment Research Council (NERC).
The main aim of the CUSTARD project is to quantify the seasonal drivers of carbon fluxes in a region of the Southern Ocean upper limb, and estimate how long different quantities of carbon are kept out of the atmosphere based on the water flow routes at the observed remineralisation depths. Please visit the CUSTARD web page for more information
CUSTARD is one of three projects funded as part of the Role of the Southern Ocean in the Earth System (RoSES) programme, also known as the Southern Ocean programme. Please see the RoSES project document for more information on the wider programme and the research projects associated with it.
Background
The upper limb of the Antarctic Circumpolar Current (ACC) represents an important junction in the marine carbon cycle, as the fate of carbon fixed by surface phytoplankton will differ according to how deep it penetrates before being remineralised. If shallow remineralisation occurs, carbon will follow the upper limb circulation and upwell further north, escaping into the atmosphere within decades. On the other hand, deep remineralisation will result in carbon entering the lower limb circulation, with the potential of being retained in the ocean for hundreds of years. Seasonality in plankton dynamics play an important role in remineralisation depth, and CUSTARD aims to resolve all factors contributing to the carbon export out of the region.
Participants
Six different UK-based organisations are directly involved in research for CUSTARD:
- National Oceanography Centre (NOC)
- NERC British Antarctic Survey (BAS)
- University of Southampton
- University of Oxford
- Plymouth University
- University of East Anglia (UEA)
CUSTARD collaborates closely with the US Ocean Observatories Initiative (OOI) program through sharing of instruments and platforms at and around the Global Southern Ocean Array. OOI is funded by the National Science Foundation (NSF) and is managed by the Woods Hole Oceanographic Institution. Rutgers University maintains the cyberinfrastructure component, working alongside CUSTARD scientists in the handling and distribution of shared observational data.
Research details
Four Work Packages have been funded by the CUSTARD project, each addressing a separate project objective within the region of study in the south eastern Pacific ocean. These are described briefly below:
-
Work Package 1: Obtain an accurate picture of the seasonal air-sea flux and macronutrient drawdown.
This work package aims at determining the magnitude and variability of air-sea CO2 fluxes and their physical and biogeochemical drivers. High-resolution carbon measurements in the water column, CO2 flux estimates and daily resolved nitrate and silicate observations are combined to better understand the link between seasonal changes in CO2 fluxes and biological variability. -
Work Package 2: Quantify the link between iron and silicate availability and remineralisation depth.
This work package investigates the annual cycle of phytoplankton dynamics, net production and export of organic material in conjunction with iron availability. -
Work Package 3: Observationally determine the seasonal cycle in remineralisation depth.
This work package assesses remineralisation depth and its variability using marine snow catchers deployed during the process cruise, and backscatter measurements carried out year-round by gliders. -
Work Package 4: Examine the link between seasonality and remineralisation depth and the trajectory of carbon from the surface out of the upper limb.
This work package aims to ingest all CUSTARD observational data into models to determine whether seasonal variability in phytoplankton composition is reflected in changes in remineralisation depth, which in turn leads to seasonal variability in the fate of organic carbon leaving the Southern Ocean via the upper limb.
Fieldwork and data collection
All the observational data from the project is collected at and south of the Ocean Observatories Initiative (OOI) Global Southern Ocean Array, located south-west of Chile. Data collection activities span from November 2018 to January 2020, and include three cruises, four glider missions, and one mooring.
Cruises
All cruises depart from and return to Punta Arenas (Chile). Cruise activities include deployments and recovery of gliders and a mooring, Conductivity, Temperature and Depth (CTD), trace metal clean GoFlo bottle sampling, Red Camera Frame, Marine Snow Catcher and Underwater Vision Profiler deployments, as well as laboratory incubations with sea water samples. See cruise details below:
Cruise identifier | Research ship | Cruise dates | Comments |
---|---|---|---|
DY096 | RRS Discovery | November - December 2018 | Deployment cruise |
DY111 | RRS Discovery | December 2019 - January 2020 | Process cruise |
DY112 | RRS Discovery | January 2020 | Mooring recovery cruise |
Gliders
Two Slocum 1000 MARS gliders (Pancake and Churchill) are deployed from DY096, to collect data continuously for one year until recovery on DY111. The gliders are mounted with CTD sensors, an optode, a fluorometer, and twin backscatter sensors. Pancake failed and its mission ended early in February 2019.
One Rutgers University glider is deployed from DY111, to collect data until recovery at the end of the same cruise. The glider is owned by Rutgers University and the data is shared with CUSTARD. It carries CTD sensors, an optode, a fluorometer, a backscatter sensor and a particle size analyser.
Mooring
Deployment of Global Surface Mooring GS01SUMO-00004 (SUMO-4) during DY096, to take continuous measurements for approximately one year until recovery during DY112. Its location is roughly 54 28 S, 89 02 W. This is an OOI mooring provided and deployed by WHOI, and adapted to integrate NOC lab-on-chip nitrate and silicate sensors.
Contacts
Dr. Adrian Marin (National Oceanography Centre, UK) - Lead Principal Investigator and lead of Work Package 4
Dr. Dorothee Bakker (University of East Anglia, UK) - Lead of Work Package 1
Prof. Mark Moore (University of Southampton, UK) - Lead of Work Package 2
Dr. Stephanie Henson (National Oceanography Centre / University of Southampton, UK) - Lead of Work Package 3
Data Activity or Cruise Information
Cruise
Cruise Name | DY112 |
Departure Date | 2020-01-16 |
Arrival Date | 2020-01-25 |
Principal Scientist(s) | Sheri White (Woods Hole Oceanographic Institution Department of Applied Ocean Physics and Engineering) |
Ship | RRS Discovery |
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 |