Metadata Report for BODC Series Reference Number 2308480

• 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

Problem Reports

No Problem Report Found in the Database

RRS James Clark Ross JR18004 LADCP (Lowered Acoustic Doppler Current Profiler) Data Quality Report

Screening and Quality Control

During BODC quality control, data were screened using in house visualisation software. The data were screened and any obvious outliers and spikes were looked at in closer detail and flagged if necessary. At the start and end of some casts, anomalous spikes were noted in the ERRVLDCP (Error velocity of water current in the water body by lowered acoustic doppler current profiler (ADCP)) parameter. Due to the regularity of spikes occurring at the start and end of casts, the vertical and horizontal velocity parameters (LCNSLW01 and LCEWLW01 respectively) in cycles associated with error velocity spikes were flagged. Overall, the quality of the LADCP data in both the vertical and horizontal velocities was noted as very high by the originator.

During tow-yo Cast 062, the originator noted that due to the experimental nature of the derivation of horizontal velocities in tow-yo casts, that the horizontal velocity parameter (LCEWLW01) should be used with caution. Further information on the derivation of the horizontal velocity in tow-yo casts may be found in the JR18004 cruise report, available here: https://www.bodc.ac.uk/resources/inventories/cruise_inventory/reports/jr18004.pdf

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

Processing by BODC of RRS James Clark Ross JR18004 LADCP (Lowered Acoustic Doppler Current Profiler) Data

These LADCP data were supplied to BODC as .mat files, alongside associated metadata files, and a DOI was minted upon submission for source files in .mat format. Basic checks were applied to the .mat data (using metadata files supplied as reference), and these data were subsequently transferred to BODC internal format (a netCDF subset). During transfer the originator's variables were mapped to unique BODC parameter codes. The following table shows the parameter mapping:

Following transfer the data were screened using BODC in-house visualisation software. Any suspect data were flagged using the BODC quality control flags.

Please note that tow-yo Cast 062 was processed by the originator to give spatial and temporal averages, and are presented as 6 individual casts.

Processing by originator of RRS James Clark Ross JR18004 LADCP (Lowered Acoustic Doppler Current Profiler) Data

Sampling Strategy

In total, 62 CTD (Conductivity-Temperature-Depth)/LADCP (Lowered Acoustic Doppler Profiler) cast deployments were undertaken during RRS James Clark Ross cruise JR18004, with the last being a 'tow-yo' of 6 profiles.

During the casts conducted on JR18004, current profiling was completed using a pair of LADCPs attached to the CTD rosette. The pair were orientated as an uplooker and a downlooker, on the side and underneath the rosette respectively. The instruments used were both 300kHz Telodyne/RDI Workhorse Monitor LADCPs, run with zero blanking distance, 8 m bins and a staggered 1.3/1.5 ping rate. The downlooker serial number for all stations 1-62 was 14443.The uplooker serial number for stations 1-49 was 14897, and was switched for a spare LADCP of the same model to check the second instrument was working. The second LADCP instrument deployed as the uplooker on stations 50-62 had the serial number 15060. In the preparation for each cast a pre-deployment script was run on both the uplooker and downlooker to check the instruments were behaving as expected. Deployment scripts were then run, first on the uplooker then the downlooker. To view the deployment scripts in further detail, please see the JR18004 Cruise Report https://www.bodc.ac.uk/resources/inventories/cruise_inventory/reports/jr18004.pdf.

Data Processing

The LADCP horizontal velocity data were processed using version IX 13 of the Matlab-based software LDEO developed by Martin Visbeck and maintained by Andreas Thurnherr at the Lamont-Doherty Earth Observatory. This software incorporates the CTD time series to constrain the sound speed and LADCP depth, the GPS time series to constrain the barotropic velocities and the Shipboard ADCP data to constrain the surface layer velocities and provide a metric for LADCP data quality. The software calculates the horizontal velocities using both the shear and velocity inversion techniques.

The CTD profiles from stations 1-61 are all standard downcast-upcast profiles, however for station 62 the science party conducted a tow-yo whereby the rosette was brought down to the seafloor then back up to 1000m and back down 6 times whilst being towed at ~0.3 knots. Processing for horizontal velocity on tow-yo cast 62 required pre-processing of the input files and post-processing of the results. Horizontal velocities for tow-yo cast 62 are thus somewhat experimental and should be used with caution. Vertical velocities on tow-yo cast 62 are unaffected and were processed using the standard software routine. LDEO_IX version IX 14 was used for processing the tow-yo profiles for horizontal velocity.

Additionally, it should be noted that the lat/lon information of the tow-yo profiles (both horizontal and vertical velocities) were measured from the ship position and not from the CTD package. Available USBL data can and should be used to derive corrections. Just like regular profiles, the horizontal velocities from the tow-yo are averages between the down- and the corresponding upcasts (vertical velocities are never averaged). Because of the towing of the package, the tow-yo profiles therefore represent both spatial and temporal averages.

Raw data were not passed to BODC, however the data were passed to BODC in structure arrays and the originator's parameters appended with 'dr'.

To find out more about how these data were processed, please visit:http://www.bodc.ac.uk/data/documents/nodb/pdf/processing_howto.pdf

Project Information

Ocean Regulation of Climate by Heat and Carbon Sequestration and Transports (ORCHESTRA)

The Ocean Regulation of Climate by Heat and Carbon Sequestration and Transports (ORCHESTRA) is a £8.4 million, five year (2016-2021) research programme funded by the Natural Environment Research Council (NERC). The aim of the research is to to advance the understanding of, and capability to predict, the Southern Ocean's impact on climate change via its uptake and storage of heat and carbon. The programme will significantly reduce uncertainties concerning how this uptake and storage by the ocean influences global climate, by conducting a series of unique fieldwork campaigns and innovative model developments.

Background

ORCHESTRA represents the first fully-unified activity by NERC institutes to address these challenges, and will draw in national and international partners to provide community coherence, and to build a legacy in knowledge and capability that will transcend the timescale of the programme itself.

It brings together science teams from six UK research institutions to investigate the role that the Southern Ocean plays in our changing climate and atmospheric carbon draw-down. It is led by British Antarctic Survey, in partnership with National Oceanography Centre, British Geological Survey, Plymouth Marine Laboratory, the Centre for Polar Observation and Modelling and the Sea Mammal Research Unit.

The oceans around Antarctica play a critical a key role in drawing down and storing large amounts of carbon and vast quantities of heat from from the atmosphere. Due to its remoteness and harsh environment, the Southern Ocean is the world's biggest data desert, and one of the hardest places to get right in climate models. The ORCHESTRA programme will make unique and important new measurements in the Southern Ocean using a range of techniques, including use of the world-class UK research vessel fleet, and deployments of innovative underwater robots. The new understanding obtained will guide key improvements to the current generation of computer models, and will enhance greatly our ability to predict climate into the future.

The scope of the programme includes interaction of the Southern Ocean with the atmosphere, exchange between the upper ocean mixed layer and the interior and exchange between the Southern Ocean and the global ocean.

Further details are available on the ORCHESTRA page.

Participants

Six different organisations are directly involved in research for ORCHESTRA. These institutions are:

• British Antarctic Survey (BAS)
• National Oceanography Centre (NOC)
• Plymouth Marine Laboratory (PML)
• British Geological Survey (BGS)
• Centre for Polar Observation and Modelling (CPOM)
• Sea Mammal Research Unit (SMRU)

GO-SHIP are a third party organisation that, although not directly involved with the programme, will conduct ship based observations that will also be used by ORCHESTRA.

Research details

Three Work Packages have been funded by the ORCHESTRA programme. These are described in brief below:

• Work Package 1: Interaction of the Southern ocean with the atmosphere
  WP1 will use new observations of surface fluxes and their controlling parameters in order to better constrain the exchanges of heat and carbon loss across the surface of the Southern Ocean.

• Work Package 2: Exchange between the upper ocean mixed layer and the interior.
  This work package will combine observationally-derived data and model simulations to determine and understand the exchanges between the ocean mixed layer and its interior.

• Work Package 3: Exchange between the Southern Ocean and the global ocean .
  This WP will use budget analyses of the hydrographic/tracer sections to diagnose the three-dimensional velocity field of the waters entering, leaving and recirculating within the Southern Atlantic sector of the Southern ocean.

• Fieldwork and data collection

  The campaign consists of 12 core cruises on board the NERC research vessels RRS James Clark Ross and RRS James Cook and will include hydrographic/tracer sections conducted across Drake Passage (SR1b), the northern Weddell Sea/Scotia Sea (A23), the northern rim of the Weddell Gyre (ANDREXII) and across the South Atlantic (24S). Section I6S will be performed by GO-SHIP Project Partners. Measurements will include temperature, salinity, dissolved oxygen, velocity, dissolved inorganic carbon, total alkalinity, inorganic nutrients, oxygen and carbon isotopes, and underway meteorological and surface ocean observations including pCO₂.

  Tags will be deployed on 30 Weddel seals and these will provide temperature and salinity profiles that can be used alongside the Argo data.

  Autonomous underwater ocean gliders will conduct multi-month missions and will deliver data on ocean stratification, heat content, mixed layer depth and turbulent mixing over the upper 1 km, with previously-unobtainable temporal resolution. These gliders will be deployed in the Weddell Gyre and the ACC.

  Field campaigns with the MASIN meteorological aircrafts will be conducted flying out of Rothera and Halley research stations and the Falkland Islands. These campaigns will deliver information on key variables relating to air-sea fluxes (surface and air temperature, wind, humidity, atmospheric CO₂, radiation, turbulent fluxes of heat, momentum and CO₂), in different sea ice conditions and oceanic regimes.

  Eart Observation datasets will be used to inform the programme on the properties of the ocean, sea ice and atmosphere and on interactions between them.

  A cluster of 6 deep ocean moorings in the Orkney Passage will collect year round series of AABW temperatre and transport. This work connects to the NERC funded project Dynamics of the Orkney Passage Outflow (DYNOPO).

  The UK Earth System model (UKESM) and underlying physical model will be used to conduct analyses of heat and carbon uptake and transport by the Southern Ocean and their links to wider climate on decadal timescales.

  An eddy-resolving (1/12°) sector model of the ocean south of 30°S with 75 vertical levels, will be built using the NEMO model coupled to the Los Alamos sea ice (CICE) model. The improvements on the ocean boundary layer will be based from the results from the NERC-funded OSMOSIS project and the inclusion of tides.

  20-5 year runs of an adjoint model will be conducted to determine how key forcings and model states affect the uptake and subduction of heat and carbon by the ocean.

Data Activity or Cruise Information

Cruise

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:

SeaDataNet Quality Control Flags

The following single character qualifying flags may be associated with one or more individual parameters with a data cycle: