Metadata Report for BODC Series Reference Number 709756

• 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

The conductivity and salinity channels show data that are not consistent with other data collected at the same time, at the same locations. The characteristics and actual values of the data are highly suspicious. Therefore, all conductivity and salinity data have been flagged suspect.

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 16 SEACAT

The SBE 16 SEACAT designed to measure and record temperature and conductivity at high levels of accuracy while deployed in either a fixed or mooring application. Powered by internal batteries, SEACAT is capable of recording data for periods of a year or more. SEACAT's precision time-base is accurate to within 3 minutes per year. An internal battery back-up is used to support memory and the real time clock in the event of instrument failure or exhaustion of the main battery supply. Communication with SEACAT is over a 3 wire RS-232C link.

Specifications

Further information can be found via the following link: Official Sea-Bird Website

RAPIDMOC Calibration Coefficients: Series 709756

Processing Log

purge_bp.m: Pressure offset of 5395.01 dbar NOT removed
purge_bp.m: 0 spikes removed

RAPIDMOC/MOCHA Sea-Bird SeaCAT data processing document

This document outlines the procedures undertaken to process and quality assure the SeaCAT 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, temperature and conductivity data in a file with a .use extension.

• filtering of the pressure data using a 2 day low pass filter to remove the diurnal and semi-diurnal tides.

• interpolating the temperature and de-trended, filtered pressure data onto a 12 hour time grid. This is stored in a file with a .seacat extension.

• calculation of a harmonic fit of the fortnightly and monthly tides. Also stored in the .seacat extension file.

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 as two files per instrument.

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.

• The pressure, temperature and conductivity channels from the .use file are combined with the pressure residual channel (de-trended and 2-day low pass filtered) from the .seacat file into a single file. In addition 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 with an extension of .use.

• 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

Meridional Overturning Circulation and Heatflux Array (MOCHA) Project

Introduction

Users of these data are referred to the Meridional Overturning Circulation and Heatflux Array (MOCHA) Project Website for more information. The following text has been taken from the website.

Scientific Rationale

To set in place a system for continuous observation of the meridional heat transport in the subtropical Atlantic, with which to document its variability and its relationship to oberved climate fluctuations, and to assess climate model predictions

Overview

MOCHA is a collaborative project, partnered with the UK RAPID Program, to measure the heat and freshwater transports of the North Atlantic Ocean. These transports are called the Thermohaline or Overturning Circulation. Simply put, warm waters move poleward at the surface of the ocean, where they cool and sink, to return equatorward in the deep ocean.

Data Activity or Cruise Information

Data Activity

RAPID Moored Instrument Rig WB5#1

This rig was deployed as part of the Western Boundary (WB) array of the MOCHA/RAPIDMOC project.

The rig was kept erect by a 56" diameter surface syntactic float with a mooring locator-strobe data logger and controller, and a 51" diameter syntactic float attached at ~1800m. 23 syntactic collar floats were also attached at regular intervals along the mooring.

Instruments deployed on the rig

The SBE16 SEACAT #1000 was fitted with a Digiquartz pressure sensor.

The Sea-Bird SBE37 IMP MicroCAT instrument at 250m depth and Sea-Bird SBE37 IMP MicroCAT instrument at 2500m depth failed to record data.

Related Data Activity activities are detailed in Appendix 1

Cruise

Complete Cruise Metadata Report is available here

Fixed Station Information

Fixed Station Information

RAPIDMOC/MOCHA Western Boundary (WB) Array

The Western Boundary Array defines a box in which moorings were deployed at the western side of the North Atlantic as part of the RAPIDMOC project and the collaborative project Meridional Overturning Circulation and Heatflux Array (MOCHA). The box region has latitudinal limits of 26° N to 27.5° N and longitudinal limits of 69.5° W to 77.5° W. Moorings have occupied this region since 2004 and are typically deployed for 6 to 18 months.

Moored data summary

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: WB5#1

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: Western 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.