Metadata Report for BODC Series Reference Number 2210169

• 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 Discovery DY113 Lowered Acoustic Doppler Current Profiler (LADCP): 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.

Improbable value ('M') flags were applied to rosette casts 77, 78, 79, and 96 (series reference numbers 2210920, 2210932, 2210944, 2211136 respectively). Improbable value flags were applied to all parameters (ERRVLDCP, LCEWLW01, LCNSLW01, ACYCAA01) due to the originator's processing software not finding the surface or the bottom correctly and this led to bad beams being found. This could be due to a number of reasons, such as it being a very shallow cast (except for 096), or the sea stat being rough, generating bubbles and turbulence.

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

Teledyne RDI's Workhorse Monitor ADCP

The Workhorse Monitor acoustic doppler current profler (Teledyne RD Instruments) is a long-range and long-term self contained ADCP. It has a patented four beam signal (300, 600 or 1200 kHz) and a standard depth rating of 200m or 600m. It operates effectively between temperatures of -5°C and 45°C and has a velocity accuracy of ±1% ±5mm/s.

Processing by BODC of DY113 LADCP (Lowered Acoustic Doppler Current Profiler) Data

The RRS Discovery departed on Cruise DY113 from Punta Arenas, Chile on 4th February 2020, and returned to Montevideo, Uruguay on 13th March 2020. In total 104 CTD (Conductivity-Temperature-Depth)/LADCP (Lowered Acoustic Doppler Current Profiler) cast deployments were undertaken during this cruise. 62 CTD/LADCP casts were taken at site SR1b (Drake Passage from Burdwood Bank to Elephant Island) and A23 (northern Weddell Sea across the Scotia Sea to South Georgia). Additionally, a further 17 CTD/LADCP deployments were made along the North Scotia Ridge, where the total 104 casts include one test cast and one repeat cast.

These LADCP data were supplied to BODC as .lad files, alongside associated .bot, .log, .mat, and .txt files. Basic checks were applied to the .lad 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.

Processing by originator of DY113 LADCP (Lowered Acoustic Doppler Current Profiler) Data

Sampling Strategy

The RRS Discovery departed on Cruise DY113 from Punta Arenas, Chile on 4th February 2020, and returned to Montevideo, Uruguay on 13th March 2020. In total 104 CTD (Conductivity-Temperature-Depth)/LADCP (Lowered Acoustic Doppler Current Profiler) cast deployments were undertaken during this cruise. 62 CTD/LADCP casts were taken at site SR1b (Drake Passage from Burdwood Bank to Elephant Island) and A23 (northern Weddell Sea across the Scotia Sea to South Georgia). Additionally, a further 17 CTD/LADCP deployments were made along the North Scotia Ridge, where the total 104 casts include one test cast and one repeat cast.

Two 330-kHz Teledyne RDI Workhorse Monitor lowered acoustic Doppler current profilers (LADCPs) were installed on the CTD rosette in a downward looking (Master, SN:23444), and upward looking (Slave, SN:12369) configuration. The data was collected in beam coordinates with 25 x 8 m bins, which were converted to earth coordinates during processing. The LADCP deployment was carried out by the NMF CTD technicians. Prior to each cast pre-deployment and deployment scripts were run to check for any faults in the LADCP, set ping, bin, and transformation parameters, and to start the LADCP heads pinging. After CTD recovery both LADCPs were connected to a laptop in the deck lab for charging, data downloading and initial quality checking, carried out by the NMF technicians. The files were saved with names of the form DY113_CTDXXXM.000 and DY113_CTDXXXS.000 for master and slave respectively, where XXX is the CTD number, and copied to the networked Sensors and Moorings drive.

Data Processing

LADCP data were processed using LDEO IX_13 inversion method on combined down- and uplooker data with GPS, bottom tracking, and OS150 VMADCP as constraints

The data were copied from the Sensors and Moorings drive to a local drive for processing by running shell script lad_linkscript.ix, which also made symbolic links with names of the form DLXXX000.000 and ULXXX000.000. Processing was completed by the physics team using version 13 of the LADCP-processing matlab package, LDEO_IX, developed at Lamont-Doherty Earth Observatory (LDEO) by Martin Visbeck and maintained by Andreas Thurnherr. This software uses an inverse method to compute velocity profiles from the LADCP data plus additional constraings: 1) position data from the ship GPS (posmv) with which cast-averaged velocity data is derived; 2) bottom tracking velocities (in most cases, calculated in the instrument); 3) shipboard ADCP velocities in the upper ocean. To check the effect of the different constraints, we added them in succession, starting with a solution using only GPS, then one using GPS and bottom tracking, and finally solutions using GPS, bottom tracking, and VMADCP velocities from either of the two instruments (75 kHz and 150 kHz). To simplify running the processing with multiple constraints, versions of the two front-end LDEO_IX scripts, process_cast.m and set_cast_params.m, were modified to accept input arguments determining which constraints would be used, and saved as process_cast_cfgstr.m and set_cast_params_cfgstr.m, respectively.

For more information on data processing, please see the DY113 Cruise Report.

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

Fixed Station Information

World Ocean Circulation Experiment (WOCE) Southern Repeat Section 1B - Falkland Islands to Elephant Island

WOCE Southern Repeat Section 1B is a section across Drake Passage in the South Atlantic Ocean. The nominal end points of the section (to date) are at 52° 55.74' S, 58° 00.00' W (at the south of the Falkland Islands) and 61° 03.05' S, 54° 33.10' W (off Elephant Island at the north end of the Antarctic Peninsula).

The section was first occupied by the R/V Polarstern in 1992 (Gersonde, 1993). The first UK occupation of SR1b followed on RRS Discovery later the same year. The National Oceanography Centre, Southampton (formerly known as Southampton Oceanography Centre), in collaboration with the British Antarctic Survey, have occupied the section most years since 1993 on the RRS James Clark Ross. Additionally, there were three Spanish occupations on R/V Hespérides in February 1995, 1996 and 1998 (Garcia et al., 2002). A Drake Passage summary report for RRS James Clark Ross cruises between 1993 - 2000 has been produced.

A table of cruises which occupied SR1b is presented below with links to the relevant cruise reports (were available).

References

García, M. A., I. Bladé, A. Cruzado, Z. Velásquez, H. García, J. Puigdefàbregas and J. Sospedra, 2002: Observed variability of water properties and transports on the World Ocean Circulation Experiment SR1b section across the Antarctic Circumpolar Current. J. Geophys. Res. 107 (C10) 3162, 10.1029/2000JC000277.

Gersonde, R., 1993: The Expedition Antarktis X/5 of RV Polarstern in 1992. Berichte zur Polarforschung, 131, 167 pp.

Related Fixed Station activities are detailed in Appendix 1

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:

Appendix 1: Drake Passage - WOCE SR1b

Related series for this Fixed Station are presented in the table below. Further information can be found by following the appropriate links.

If you are interested in these series, please be aware we offer a multiple file download service. Should your credentials be insufficient for automatic download, the service also offers a referral to our Enquiries Officer who may be able to negotiate access.