Metadata Report for BODC Series Reference Number 1899963

• 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

The data were screened by BODC using in house visualisation software where any obvious outliers and spikes were looked at in closer detail and flagged if necessary but it was not deemed that any points were anomalous.

The PRESPR01 channel is not monotonic throughout the casts which has resulted in 'loops' in the profiles. These loops have not been flagged during BODC processing but 'B' and 'E', flags representing the beginning and end of the downcast respectively, have been added to the data. These flags have elimiated any of these loops which occur at the beginning and end of the downcasts from the profiles.

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

Sound Profiles from cruise JC132 Instrumentation

A Valeport MIDAS Sound Velocity Probe (serial number 22241) was deployed three times during cruise JC132 to collect sound velocity profile data. The probe was last calibrated on 31st July 2014.

A description of the probe can be found here.

Valeport MIDAS Sound Velocity Probe

The Valeport MIDAS Sound Velocity Probe (SVP) is fitted with a time of flight sound velocity sensor, a pressure transducer and a fast response platinum resistance temperature sensor. The instrument was formerly known as the Valeport Model 650 Mk2 SVP.

Specifications

Measurement Range:

• Temperature: -5 to +35 °C
• Pressure: to a depth of 3000 or 6000 metres
• Speed of sound: 1375-1900 m.sec^-1

Accuracy:

• Temperature: 0.01 °C
• Pressure: 0.01 % of range
• Speed of sound: 0.02 m.sec^-1

Resolution:

• Temperature: 0.005 °C
• Pressure: 0.001 % of range
• Speed of sound: 0.001 m.sec^-1

Further details can be found in the manufacturer's specification Sheet

Sound Profiles from cruise JC132 BODC Processing

Data Processing

Raw, sorted and thinned sound profile data were submitted to BODC as ASCII files which were archived following BODC procedures. The files were also accompanied by header files which contained some metadata. Further metadata can be found in the cruise report. The sorted profiles were produced by sorting the raw data by depth order using manufacturer's editing software. The thinned profiles were produced by sorting the profiles into depth order, extrapolated to a depth of 12 km using climatologies and thinned taking every fifth datacycle, again using manufacturer's editing software. The sorted files were transferred to BODC internal format using standard BODC processing procedures. The raw data and thinned profiles are available on request.

The variables provided in the file were mapped to BODC parameter codes as follows:

Screening

Post transfer analysis and crosschecks were applied according to BODC procedures. This involved the screening of data using BODC's in house visualisation software where any suspect data were flagged but not removed.

Sound Profiles from cruise JC132 Originator Processing

Sampling Strategy

Three sound velocity profiles (SVP) were conducted during cruise JC132 using a Valeport Midas sound velocity probe. The first was conducted one day out of Mindelo (departure port), the second was in the north of the work area (13°N on the Mid-Atlantic Ridge) and the third in the south of the work area while waiting for an opportunity to deploy an Autosub. The second profile was used to calibrate the EM120 swath bathymetry system and the third to check that that calibration was still valid. The third deployment also took the opportunity to profile the entire water column in the deepest part of the study area. The probe was attached the a OBS acoustic realease frame each time it was deployed.

Data Processing

The raw files were downloaded from the instrument and then processed using the SVP Editor in the Kongsberg SIS program. A file was then produced containing the sound velocities and depths of the entire cast. The profile was extended to 12000m and then thinned by the SVP editor with a scale factor of 0.2. The thinned file was then loaded into SIS on the EM120. The same profiles were loaded into the USBL system (the system used to track the Autosub on deployment and recovery).

Project Information

Role and extent of detachment faulting at slow-spreading mid-ocean ridges

This is a 6 year project that aims to determine (1) the sub-surface geometry and extent of the detachments beneath the ridge axis, (2) the amount and detailed distribution of magmatic crust, and (3) the asymmetry of spreading rates associated with oceanic core complexes and the volcanic seafloor.

The research aims to make an improvement in our overall understanding of the nature and geometry of ocean detachments.

This project was funded by Natural Environment Research Council parent and child grants NE/J022551/1, NE/J02029X/1, and NE/J021741/1 led by Professor Tim Reston at the University of Birmingham, Professor Christine Pierce at Durham University, and Professor Chris MacLeod at Cardiff Univserity respectively. The project is funded from April 2013 to August 2020.

Data Activity or Cruise Information

Cruise

Complete Cruise Metadata Report is available here

Fixed Station Information

No Fixed Station Information held for the Series

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: