Metadata Report for BODC Series Reference Number 2052883

• 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

JC112 Moored MicroCATs data quality report

M2 mooring

Data from all sensors on Mooring M2 begin at shallower depths than for the rest of deployment. This difference is small and the associated Temperature (TEMPPR01) and Conductivity (CNDCPR01) values are deemed to be good quality, therefore no flags have been applied.

CNDCPR01

The conductivity channel (CNDCPR01) for MicroCAT serial no. 09399, which was deployed on the OSCAR ADCP West mooring, was not provided by the originator due to a bad conductivity reading.

The originator reported that MicroCAT serial no. 09395, which was deployed on Mooring M3 at approximately 1960 m depth, had a drift almost one order larger than any other MicroCAT: around 1 x 10-2 mS/cm/month. Thus, the conductivity (CNDCPR01) measurements of this MicroCAT have been given an improbable value flag at the originator's request, BODC flag 'L'.

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

Sea-Bird SBE 37 SMP {MicroCAT-CTP} (submersible) CTD logger

A high accuracy conductivity and temperature recorder with an integrated pressure sensor designed for deployment on moorings. The SM model uses a serial interface (SM) for real-time data transmissions and has internal batteries. The device is fitted with an integral pump (P).

For more information, please see this document: https://www.bodc.ac.uk/data/documents/nodb/pdf/SeaBird-datasheet-SBE37-SMP-July18.pdf

Processing by BODC of Moored MicroCATs: JC112

The SBE 37 MicroCAT data were supplied to BODC as ASCII files representing the data collected from MicroCAT sensors deployed at the OSCAR project M1, M2, M3, ADCP East, and ADCP West sites during RRS James Cook cruise JC112.

During transfer to BODC internal format (QXF) the originator's variables were mapped to unique BODC parameter codes. The following table shows the paramater mapping:

Following transfer the data were screened using BODC in-house visualisation software. Suspect data values were assigned the appropriate BODC data quality flag. Missing data values, where present, were changed to the missing data value and assigned a BODC data quality flag.

Processing by originator of Moored MicroCATs: JC112

Sampling Strategy

During the RRS James Cook cruise JC112, 6 Seabird MicroCATs were deployed at the OSCAR M1 site, 6 at the OSCAR M2 site, and 6 at the OSCAR M3 site. Additionally, a MicroCAT was deployed at the OSCAR ADCP East site and another at the OSCAR ADCP West site. All of the MicroCATS were set to record temperature, conductivity, and pressure every 60 seconds. These moorings were recovered during the RV Sonne cruise SO238.

Data Acquisition and Initial Processing

The MicroCATs were calibrated against the CTD sensors. The MicroCATs were positioned on the CTD rosette and deployed before and after their deployment on the mooring. The calibrations were carried out based on 20 minute bottle stops at 5 depths below 1500 m. The CTD sampling frequency was set to 24 Hz during JC112, and 4 Hz during SO238, while the MicroCATs were always set to sample at their maximum rate of 0.1 Hz. The calibration of the pressure sensor was done by estimating the mean offset from the CTD pressure sensor's measurement for each calibration stop. The largest correction was applied to the deepest MicroCATs and was approximately 10 decibars. The drift for the deployment period of one month was insignificant. The conductivity and temperature calibration is considered depth-independent. Thus, data from all five calibration stops were merged to evaluate the calibration constants. The MicroCAT on mooring ADCP West produced bad conductivity readings throughout the deployment. The conductivity sensors of most of the MicroCATs had a drift in the range of 1 x 10^-3 mS/cm/month to 2 x 10^-3 mS/cm/month. However, MicroCAT serial no. 09395, deployed on Mooring 3 at about 1960 m depth had almost one order larger drift than any other MicroCAT: about 1 x 10^-2 mS/cm/month. Thus, measurements of this MicroCAT should be flagged. The temperature sensor drift for most of the MicroCATs was in the range of 1 x 10^-3 K/month to 2 x 10^-3 K/month.

More information can be found in the RV Sonne SO238 cruise report.

The processed data were supplied to BODC for banking.

Project Information

Oceanographic and Seismic Characterisation of heat dissipation and alteration by hydrothermal fluids at an Axial Ridge (OSCAR)

Background

The cooling of young oceanic crust is the main physical process responsible for removing heat from the solid Earth to the hydrosphere. Close to the mid-ocean ridge rapid cooling is dominated by hydrothermal circulation of seawater through the porous and fractured basalt crust. This hydrothermal fluid is then discharged into the ocean mainly along the ridge. Once in the ocean, released heated seawater mixes with the ambient cold water to form a plume, which provides a mechanism to lift the densest waters away from the bottom boundary layer. These waters are then more readily available for further mixing and heating as part of the global thermohaline circulation system.

The data collected as part of the interdisciplinary OSCAR project will be used to investigate the effects of heat loss and hydrothermal circulation in both the solid Earth and the ocean.

The aim is to:

1. Characterise how heat from the interior of the Earth is transported across the crust into the ocean by hydrothermal flows
2. Determine the impact the hydrothermal and geothermal fluxes have on the circulation of the abyssal ocean and on the evolution of the oceanic crust.

With this aim, the data will be used to derive a new integrated model of the ocean and hydrothermal circulations at active ocean ridges and ridge flanks. The model will be constrained by geophysical, geological, and physical oceanography data and include fluxes through a permeable seabed. These data and resultant models will set a new benchmark for integrated multi-physics experiments. They will result in a new understanding of the fluid and heat fluxes at ocean ridges and a better understanding of what geophysical and oceanographic data actually resolve in the context of an oceanic axial ridge setting. The result is also a predictive model that can be applied to similar ocean ridge systems world-wide.

Fieldwork

Data collection took place in the Panama Basin, bounded in the north-west by the Cocos Ridge, by the Carnegie Ridge in the south and by South and Central America in the east and north, respectively. Measurements were collected during RRS James Cook cruises JC112 and JC113 (05/12/2014 to 16/01/2015), RRS James Cook cruise JC114 (22/01/2015 to 08/03/2015) and RV Sonne cruise SO328 (06/02/2015 to 06/03/2015). Data were collected using Bottom Pressure Recorder, Acoustic Doppler Current Profiler (ADCP), Magnetotelluric Lander, CTD, Vertical Microstructure Profiler, Synthetic Aperture Radar, Ocean-bottom seismograph and Multibeam echosounder. Measurement of salinity, oxygen and helium were also made and zooplankton samples collected with vertical net casts.

Participants

• Professor Richard W Hobbs (Principal Investigator - Parent Grant) Durham University
• Professor Christine Peirce (Co-Investigator) Durham University
• Professor Christopher J Ballentine (Co-Investigator) University of Oxford
• Professor Joanna V Morgan (Co-Investigator) Imperial College London
• Dr Miguel Morales Maqueda (Principal Investigator - Child Grant) Newcastle University
• Dr David A Smeed (Co-Investigator - Child Grant) National Oceanography Centre
• Dr Vincent CH Tong (Principal Investigator - Child Grant) Birkbeck College

Funding

This project was funded by Natural Environment Research Council parent grant NE/I027010/1 and child grants NE/I022868/1, NE/I022868/2, NE/I022957/1, and NE/I022957/2, entitled 'OSCAR - Oceanographic and Seismic Characterisation of heat dissipation and alteration by hydrothermal fluids at an Axial Ridge', with the former, parent grant led by Professor Richard W Hobbs, Durham University, and the latter child grants led by Dr Miguel Morales Maqueda, Newcastle University and Dr Vincent CH Tong, Birkbeck College.

Data Activity or Cruise Information

Data Activity

OSCAR - M3 mooring

The mooring was a series of sphere floats and sensors attached to the seabed by a 800 kg anchor. The top float was a sub-surface Billings float.

Instruments deployed on the mooring

Instrument depths listed below are approximate.

Related Data Activity activities are detailed in Appendix 1

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:

Appendix 1: OSCAR_M3

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.