Metadata Report for BODC Series Reference Number 1721102

• 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 Quality Report

NW mooring

Data were unavailable from Sontek Argonaut current meter (#332) after 07/09/2010. The Aanderaa Seaguard recording current meters on this mooring continued to record until the mooring was recovered December 2010. There is no explanation in the JC054 recovery cruise report (p.129) as to why this series is truncated.

M mooring

Sea-Bird SBE37 IMP MicroCAT (#3889) did not record data for the first 23 days of deployment.

Data were unavailable from Sontek Argonaut current meter (#278) after 04/10/2010, so there is a 2 month data gap at the end of the record.

NE mooring

Data were unavailable from Sea-Bird SBE37 IMP MicroCAT (#4063) and Sea-Bird SBE37 SMP MicroCATs (#7292, #7293, #7294, #7295) after 27/01/2010 due to two severe knockdown events on 24th and 27th January 2010 (~200db at uppermost instrument). Therefore data are only available for the first 6 weeks of deployment.

Data were unavailable from Nortek Aquadopp current meter (#5883) and Aanderaa Seaguard recording current meters (#113, #116, #118) after 27/01/2010. This matches the knockdown events in January 2010 which affected the MicroCATs on this mooring.

SW mooring

Data were unavailable from Sea-Bird SBE37 IMP MicroCAT (#4465) and Sea-Bird SBE37 SMP MicroCATs (#7300, #7301, #7302, #7303) after 03/02/2010 due to this mooring experiencing similar knockdown events to those of the NE mooring. Good data are only available until this date, a week later than the NE mooring.

Data were unavailable from Sontek Argonaut (#298) and Aanderaa Seaguard recording current meters (#123, #124, #125, #127) after 03/02/2010. This matches the knockdown events which affected the MicroCATs on this mooring.

Data Access Policy

Public domain 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.

The recommended acknowledgment is

"This study uses data from the data source/organisation/programme, provided by the British Oceanographic Data Centre and funded by the funding body."

Narrative Documents

Aanderaa SEAGUARD Recording Current Meter

A multi-frequency Doppler current sensor for measuring horizontal current speed and direction. The shallow water (SW), intermediate water (IW) and deep water (DW) models can be deployed to 300 m, 2000 m and 6000 m, respectively. The instrument has a maximum sampling rate of 0.5 Hz, a velocity range of 0 - 300 cm/s, and incorporates an electronic compass and a tilt sensor. A number of additional oceanographic sensors may also be attached.

Further details can be found in the manufacturer's specification sheet.

DIMES Current Meter data processing document

This document outlines the procedures undertaken to process and quality assure current meter data collected under the DIMES project. These procedures follow those of the RAPIDMOC and MOCHA projects, which are outlined below.

Originator's processing

The raw data are downloaded from the instrument and converted to ASCII format.

Once in ASCII format the data are corrected for the following -

• Speed bias (caused by the mooring motion)
• Sound speed (as electromagnetic current meter sensors use the speed of sound in water to calculate the doppler shift in the returned signal, they are corrected for variations in sound speed using temperature data as sound speed varies with temperature).
• Magnetic variation

A 40 hour low pass filter is also applied to the data.

Calculating and applying calibrations

Manufacturers calibrations are applied.

Quality Control

Data were visually inspected for out-lying data and instrument electrical spikes removed.

BODC processing

Data are received after quality checks have been made and calibrations have been applied. The data files are submitted in ASCII format as one file per instrument.

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

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

• Standard parameter codes are assigned 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.

Nortek Aquadopp 6000 3D Doppler current meter and SonTek Argonaut moored 3D doppler current meter

Aanderaa Seaguard Recording Current Meter

Project Information

Diapycnal and Isopycnal Mixing Experiment in the Southern Ocean (DIMES) project document

DIMES is a US/UK field program aimed at measuring diapycnal and isopycnal mixing in the Southern Ocean, along the tilting isopycnals of the Antarctic Circumpolar Current.

The Meridional Overturning Circulation (MOC) of the ocean is a critical regulator of the Earth's climate processes. Climate models are highly sensitive to the representation of mixing processes in the southern limb of the MOC, within the Southern Ocean, although the lack of extensive in situ observations of Southern Ocean mixing processes has made evaluation of mixing somewhat difficult. Theories and models of the Southern Ocean circulation have been built on the premise of adiabatic flow in the ocean interior, with diabatic processes confined to the upper-ocean mixed layer. Interior diapycnal mixing has often been assumed to be small, but a few recent studies have suggested that diapycnal mixing might be large in some locations, particularly over rough bathymetry. Depending on its extent, this interior diapycnal mixing could significantly affect the overall energetics and property balances for the Southern Ocean and in turn for the global ocean. The goals of DIMES are to obtain measurements that will help us quantify both along-isopycnal eddy-driven mixing and cross-isopycnal interior mixing.

DIMES includes tracer release, isopycnal following RAFOS floats, microstructure measurements, shearmeter floats, EM-APEX floats, a mooring array in Drake Passage, hydrographic observations, inverse modeling, and analysis of altimetry and numerical model output.

DIMES is sponsored by the National Science Foundation (U.S.), Natural Environment Research Council (U.K) and British Antarctic Survey (U.K.)

For more information please see the official project website at DIMES

Data Activity or Cruise Information

Data Activity

DIMES Moored Instrument Rig NE_1_200912

This rig was deployed as part of the mooring array of the DIMES (Diapycnal and isopycnal mixing experiment in the Southern Ocean) project.

The rig was anchored by a 1950 kg dead weight and kept erect with groups of glass spheres and floats distributed along the mooring.

Instruments deployed on the rig

* Aanderaa RCM 11 Recording Current Meter (#300) was flooded on recovery, so was jettisoned for safety reasons.

Related Data Activity activities are detailed in Appendix 1

Cruise

Complete Cruise Metadata Report is available here

Fixed Station Information

Fixed Station Information

Drake Passage

The World Ocean Circulation Experiment (WOCE, 1990-1998) was a major international experiment which made measurements and undertook modelling studies of the deep oceans in order to provide a much improved understanding of the role of ocean circulation in changing and ameliorating the Earth's climate.

The Drake Passage is the narrowest constriction of the Antarctic Circumpolar Current (ACC) - the largest current in the world and connects all three major oceanic basins both horizontally and vertically, thus being a key control in the global overturning circulation.Within the Drake Passage, two repeat hydrographic sections (SR1 and SR1b) were established by WOCE. These were designed to extend measurements collected earlier by the International Southern Ocean Studies (ISOS) programme and have continued beyond the WOCE time-frame.

The original section was SR1 (which also covers part of the A21 one time survey track). Subsequently, the section was shifted to the east (and designated SR1b) in order for it to lie on a satellite ground track as illustrated in the image below.

In addition to the hydrographic measurements, UK research in Drake Passage also includes a network of coastal and deep tide gauges, analysis of satellite altimeter data, and state-of-the-art global numerical modeling.

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: NE_1_2009

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: Drake Passage

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.