Metadata Report for BODC Series Reference Number 1971684

• 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

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

Sea-Bird SBE-26 SEAGAUGE Wave and Tide Recorder

The SEAGAUGE SBE 26 is a wave & tide recorder manufactured by Sea-Bird Electronics (www.seabird.com) which integrates water level measurements and characterizes waves with interleaved bursts of sampling at up to 4 Hz. The SBE 26 combines a Digiquartz pressure sensor, accurate clock, precision thermometer and optional conductivity sensor.

The SEAGAUGE SBE 26 continuously integrates pressure samples to obtain water level measurements unaffected by wave action, and also independently burst-samples pressure at rates up to 4 Hz for wave amplitude calculation. Water level integration and wave burst sampling intervals are programmable. The large memory permits frequent water level recording and detailed wave characterization.

Specifications

Pressure

Temperature [°C]

Sea-Bird software processing

Default data processing is carried out using the manufacturer's software package ('SEASOFT for Waves') which performs auto-spectrum and time-series analyses and provides facilities for deployment planning, instrument set- up, data retrieval and plotting.

RAPIDMOC Calibration Coefficients

Processing Log

Clock offset at recovery of -457 s (relative to UTC)
Calculated a linear trend going through jd([1 end]) and [0 ] and subtracted it from the recorded time

purge_bp_003.m: Pressure offset of 9.73 dbar NOT removed
purge_bp_003.m: 0 spikes removed

Linear pressure fit to be stored with data:
linear slope: 0.000030 db/day
mean offset: 3097.116254 db

RAPIDMOC/MOCHA Sea-Bird SEAGAUGE data processing document

This document outlines the procedures undertaken to process and quality assure the SEAGAUGE data collected under the RAPIDMOC and MOCHA projects.

Originator's processing

The raw data are downloaded from the instrument and converted to ASCII format. All processing is performed in Matlab.

Processing

Processing steps which are undertaken include

• calculation and removal of a post recovery clock offset.

• calculation of a pressure offset for atmospheric correction. However, this may not be applied. See the calibration coefficients documents for each series for more information.

• calculation of an exponential-linear or pure linear pressure fit. This is stored with pressure and temperature data in a file with a .use extension.

Quality control

All variables in specified time intervals can be set to dummy values if the data are suspicious. Any data deemed as suspicious, i.e. a spike, are removed.

BODC processing

Data are received after quality checks have been made and calibrations have been applied by the originator. The data files are submitted in ASCII format.

Once the submitted data files are safely archived, the data undergo reformatting and banking procedures:

• The data are transferred into a common format, a NetCDF subset.

• A de-trended, unfiltered pressure (measured variable) series is derived by subtracting the calculated trend from the observed pressure, which were supplied in the originator's files.

• Standard parameter codes are assigned to each channel that accurately describe the data (see Parameter mapping section below).

• Unit conversions are applied, if necessary, so that units are standardised (see Parameter mapping section below).

• The data are screened visually and any spikes or instrument malfunctions can be clearly labelled with quality control flags.

• Comprehensive documentation is prepared describing the collection, processing and quality of each data series.

• Detailed metadata and documents are loaded to the database and linked to each series so that the information is readily available to future users.

Parameter mapping

The following describes the parameters contained in the originator's files and their mapping to BODC parameter codes :

Parameter derivation

The following describes the parameters derived by BODC and their mapping to BODC parameter codes:

Project Information

Monitoring the Meridional Overturning Circulation at 26.5N (RAPIDMOC)

Scientific Rationale

There is a northward transport of heat throughout the Atlantic, reaching a maximum of 1.3PW (25% of the global heat flux) around 24.5°N. The heat transport is a balance of the northward flux of a warm Gulf Stream, and a southward flux of cooler thermocline and cold North Atlantic Deep Water that is known as the meridional overturning circulation (MOC). As a consequence of the MOC northwest Europe enjoys a mild climate for its latitude: however abrupt rearrangement of the Atlantic Circulation has been shown in climate models and in palaeoclimate records to be responsible for a cooling of European climate of between 5-10°C. A principal objective of the RAPID programme is the development of a pre-operational prototype system that will continuously observe the strength and structure of the MOC. An initiative has been formed to fulfill this objective and consists of three interlinked projects:

• A mooring array spanning the Atlantic at 26.5°N to measure the southward branch of the MOC (Hirschi et al., 2003 and Baehr et al., 2004).
• Additional moorings deployed in the western boundary along 26.5°N (by Prof. Bill Johns, University of Miami - project MOCHA) to resolve transport in the Deep Western Boundary Current (Bryden et al., 2005). These moorings allow surface-to-bottom density profiles along the western boundary, Mid-Atlantic Ridge, and eastern boundary to be observed. As a result, the transatlantic pressure gradient can be continuously measured.
• Monitoring of the northward branch of the MOC using submarine telephone cables in the Florida Straits (Baringer et al., 2001) led by Dr Molly Baringer (NOAA/AOML/PHOD) - Western Boundary Time Series (WBTS) project.

The UK-led monitoring array system was recovered and redeployed annually until 2008 under RAPID funding. From 2008 until 2015 the array continued to be serviced annually under RAPID-WATCH funding. From 2015 until 2021 the array was serviced under RAPID-AMOC funding. Since 2022 the servicing of the array has continued to be funded by the Natural Environment Research Council (NERC). The US-led projects are funded by the National Science Foundation (NSF) (MOCHA project) and NOAA Office of Climate Observations (WBTS project).

The array will be focussed on three regions, the Eastern Boundary (EB), the Mid Atlantic Ridge (MAR) and the Western Boundary (WB). The geographical extent of these regions are as follows:

• Eastern Boundary (EB) array defined as a box with the south-east corner at 23.5°N, 25.5°W and the north-west corner at 29.0°N, 12.0°W
• Mid Atlantic Ridge (MAR) array defined as a box with the south-east corner at 23.0°N, 52.1°W and the north-west corner at 26.5°N, 40.0°W
• Western Boundary (WB) array defined as a box with the south-east corner at 26.0°N, 77.5°W and the north-west corner at 27.5°N, 69.5°W

References

Baehr, J., Hirschi, J., Beismann, J.O. and Marotzke, J. (2004) Monitoring the meridional overturning circulation in the North Atlantic: A model-based array design study. Journal of Marine Research, Volume 62, No 3, pp 283-312.

Baringer, M.O'N. and Larsen, J.C. (2001) Sixteen years of Florida Current transport at 27N Geophysical Research Letters, Volume 28, No 16, pp3179-3182

Bryden, H.L., Johns, W.E. and Saunders, P.M. (2005) Deep Western Boundary Current East of Abaco: Mean structure and transport. Journal of Marine Research, Volume 63, No 1, pp 35-57.

Hirschi, J., Baehr, J., Marotzke J., Stark J., Cunningham S.A. and Beismann J.O. (2003) A monitoring design for the Atlantic meridional overturning circulation. Geophysical Research Letters, Volume 30, No 7, article number 1413 (DOI 10.1029/2002GL016776)

RAPID Climate Change - Atlantic Meridional Overturning Circulation (RAPID-AMOC)

RAPID-AMOC is an £8.4 million, 7 year (2013-2020) research programme that builds on the success of the Natural Environment Research Council's (NERC) RAPID and RAPID-WATCH programmes and will deliver a 16 year long time series of the Atlantic Meridional Overturning Circulation (AMOC).

Background

The Atlantic Meridional Overturning Circulation (AMOC) is a critical element in the energy balance of the global climate system. The AMOC consists of a near-surface, warm northward flow of ocean water, compensated by a colder southward return flow at depth. This heat is transferred from the ocean to the atmosphere at mid-latitudes, with a substantial impact on climate and, in particular, on that of the UK and northwest Europe.

Observing and understanding changes in the AMOC is critically important for identifying the mechanisms of decadal climate variability and change, and for interannual-to-decadal climate prediction. This includes predicting changes in the location, frequency and intensity of Atlantic hurricanes, storms in the North Atlantic and over Europe, shifts in tropical and European precipitation patterns, and the response of sea level to changing radiative forcing. Sustained observations are also critical for assessing the possibility of abrupt change in the AMOC that are known to occur in palaeoclimatic records.

Since 2004 the NERC RAPID and RAPID-WATCH programmes, in partnership with the National Science Foundation and the National Oceanic and Atmospheric Administration in the US, have supported an observing system to continuously measure the AMOC at 26.5°N via a trans-basin array of moored instruments. This measures the basin-wide strength and vertical structure of the AMOC, and its components.

Observations from the array have already revolutionised understanding of AMOC variability and documented its variability on seasonal to interannual timescales. The first few years of observations, demonstrated the feasibility of AMOC measurement, provided new insights into the seasonal cycle, and allowed apparent trends in previous historical 'snapshots' to be seen in the context of natural variability. RAPID-AMOC will extend the AMOC time series.

Objective

RAPID-AMOC's overall objective is to determine the variability of the AMOC, and its links to climate and to the ocean carbon sink, on interannual-to-decadal time scales

This will be achieved by the continued support of the monitoring array and supporting the use of the data in three key areas:

• Application of array data for improved ocean state estimation;
• Use of array data to understand the role of the AMOC in climate variability and predictability;
• Addition of biogeochemical sensors to the array and use to constrain biogeochemical fluxes.

Three projects have been funded to address the objectives of RAPID-AMOC:

• Reanalysis of the AMOC
• DYNamics and predictability of the Atlantic Meridional Overturning and Climate (DYNAMOC)
• Atlantic BiogeoChemical fluxes (ABC Fluxes)

Data Activity or Cruise Information

Data Activity

RAPID Moored Instrument Rig EBH1L11_11

This rig was deployed as part of the Eastern Boundary (EB) array of the RAPIDMOC project.

The rig was anchored by a 600 kg anchor and kept erect by sub-surface floats attached along the mooring rope.

Instruments deployed on the rig

Related Data Activity activities are detailed in Appendix 1

Cruise

Complete Cruise Metadata Report is available here

Fixed Station Information

Fixed Station Information

RAPIDMOC Eastern Boundary (EB) Array

The Eastern Boundary Array defines a box in which moorings are deployed at the eastern side of the North Atlantic as part of the RAPIDMOC project. The box region has latitudinal limits of 23.5° N to 29° N and longitudinal limits of 12° W to 25.5° W. Moorings have occupied this region since 2004 and are typically deployed for 6 to 18 months.

Moored data summary

A description of the data types can be found at the bottom of this document.

Cruise data summary

During the cruises to service the moored array, a variety of data types are collected. The table below is a summary of these data. The number of CTD profiles performed on these cruises within the box region defined above is also included. Trans-Atlantic hydrographic CTD sections have also been performed since 2004 and are included in the table.

Data type ID and description

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: EBH1L11_11

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: Eastern Boundary Array

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.