Metadata Report for BODC Series Reference Number 2022261

• 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

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

Nortek Aquadopp Open Water Current Meter

This instrument provides 3D acoustic doppler current measurements along with standard measurements of temperature, pressure, tilt and direction. It can be used in real time measurement situations or can log to an internal recorder powered by internal batteries. It can also be configured to measure surface wave height, period and direction concurrently. It has the unique feature of being run in 'diagnostic' mode when set to collect data at 1 Hz frequency in user specified intervals. This allows studies of mooring motion and the performance of other current meters to be conducted. It can be set in various configurations with titanium housings for deployment at greater depths.

Standard Measured Parameters

• 3D current velocity (East/North/Up, X/Y/Z or Beam 1/2/3)

• Acoustic signal strength (Beam 1/2/3)

• Compass

• Tilt

• Temperature

• Pressure

• Battery voltage

• Status code

• Error code

Surface wave monitoring

The standard Aquadopp is suitable for measuring surface wave height, period, and direction, which are calculated using the PUV method whereby spectra are estimated based on a combination of the pressure signal recorded by the instrument (P) and two horizontal components of the wave orbital velocity (U and V). More specifically, the pressure signal is used to provide an estimate of the wave frequency spectrum. The energy in this spectrum is then used to estimate wave height and period. The measurements of the wave orbital velocities are used to provide an estimate of the wave direction. Since these estimates are based on the distribution of wave energy and are not direct measurements of the free surface, they should be considered inferred estimates.

Both the dynamic pressure and the orbital velocities are driven by surface waves. The signals that are associated with these properties are complicated by the fact that they attenuate (that is the signals are weaker) with depth. The exact behaviour of the attenuation is determined by the water depth and the wavelength being observed. The greater the water depth the greater the attenuation; likewise, the shorter the wavelength (or higher the frequency of the wave) the greater the attenuation for a given water depth. This means that the estimation of wave parameters is limited by both water depth and wave frequency.

Specifications

Further details can be found in the manufacturer's specification sheets for the Aquadopp, Aquadopp 3000 and Aquadopp 6000.

BODC Processing

Data processing

The data arrived at BODC as individual .mat files containing data collected on moorings OP1, OP2, OP3, OP4, OP5, OP6, OP7, CI1 and CI2. They were submitted as part of an accession which includes data from several mooring instruments e.g. ADCP, Aquadopp, RCM8, RCM11, RBR, SBE37 and SBE39.

Reformatting

The parameters from the originator's files were reformatted to internal format using BODC standard procedures.

The following parameters from the Aquadopp data were not reformatted as they are considered metadata or are not environmental variables: date, depth (m), botdepth (m), lat/lon, mooringname, nomdepth (m), serial_no, type, temp_offset_applied and press_offset_applied.

The table below includes the final variables and how they were mapped to the appropriate BODC parameter codes:

Battery voltage and amplitude channels were reformatted to help with the screening process and are not included in the final file but are avaiable upon request.

None of the parameters required a unit conversion and no derived parameters were created during reformatting.

Screening

The reformatted data were visualised using in house software and spikes or improbable values were flagged accordingly.

Originator's Data Processing

Sampling Strategy

Sampling was carried out as part of the BAS LTMS (British Antarctic Survey Long Term Monitoring and Survey) until 2016. From 2016 onwards the moorings are split between 'The Ocean Regulation of Climate by Heat and Carbon Sequestration and Transports (ORCHESTRA)' project and 'Dynamics of the Orkney Passage Outflow (DynOPO)' project.

The projects involve the deployment of moorings CI1, CI2, OP1, OP2, OP3, OP4, OP5, OP6 and OP7 in the Southern Ocean, situated north of Coronation Island and the Orkney Passage in the Weddell and Scotia Sea.

Moorings CI1 and CI2 were deployed from 2005 to 2007 and moorings OP1, OP2, OP3, OP4, OP5 and OP6 have been continuously maintained since 2007 with the addition of OP7 in 2015.

Aquadopp Deep Water current meters data have been collected at 15 minute intervals since 2011. Gaps in the series may be related to either instruments not being recovered, or data not being collected due to instrument malfunction.

Data Processing

Little information is known with regards to the exact details of the calibrations carried out on the mooring data. Originator's data processing, visualisation and calibration were done through the use of Matlab scripts written for Matlab R2014b version.

The originator did not apply corrections to current velocity, direction or components for magnetic variation for the data from 2011 to 2013 as the variation in this region is less than one degree.

According to the originator, it has been found that in some conditions Aquadopp current meters overread current speeds compared with a mechanical vector measuring current meter and there is considerable uncertainty associated with the exact corrections that should be applied. Because of the continuing uncertainties of how best to correct for the differing characteristics of these instruments, no correction has been applied to these data.

Offsets applied to the data were:

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

Data Activity

Orkney Passage Mooring 1 (OP1)

The mooring was deployed at the following positions:

The mooring was deployed on the Orkney Passage on cruise JR16005 on 18 April 2017 and recovery was done on cruise JR18004 on 29 January 2019.

The table below lists the instruments deployed on this mooring:

Related Data Activity activities are detailed in Appendix 1

Cruise

Complete Cruise Metadata Report is available here

Fixed Station Information

Fixed Station Information

Orkney Passage OP1 site

Site OP1 is part of the Orkney Passage mooring array which is an activity covered by the Long Term Monitoring and Survey British Antarctic Survey's (BAS) programme.The data collection is the result of an ongoing collaboration between BAS and the Lamont-Doherty Earth Observatory (LDEO).

This site was previously occupied in 2007 by an LDEO mooring (M4) and from 2011 onwards it became BAS's responsibility and was assigned its current name. The recovery/deployment history, including position details is presented below:

Recovery of this mooring was not possible in 2009, during ES033a, cruise due to an unresponsive release. It was re-deployed again in 2011.

Related Fixed Station activities are detailed in Appendix 2

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: OP1

Related series for this Data Activity 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.

Appendix 2: Orkney Passage OP1

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.