Metadata Report for BODC Series Reference Number 1964872

• 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

RRS James Cook JC156 Meteorology Quality Control Report

Wind sensors

Some absent data values and spiking recorded in wind channels. These were detected and flagged accordingly.

Light sensors

All PAR and TIR channels display consistent negative readings during night time and were flagged accordingly. Offsets between the port and starboard TIR & PAR pairs suggest shading during the day and were also flagged.

Air temperature, relative humidity and atmospheric pressure

Temperature, Pressure and Humidity readings are within their expected ranges. Other than what appears to be a sensor malfunction on 25/01/2018, there are no signs of discontinuity or stuck values.

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

RRS James Cook cruise JC156 Underway Document

Cruise Details

Gill Instruments Windsonic Anemometer

The Gill Windsonic is a 2-axis ultrasonic wind sensor that monitors wind speed and direction using four transducers. The time taken for an ultrasonic pulse to travel from the North to the South transducers is measured and compared with the time for a pulse to travel from South to North. Travel times between the East and West transducers are similarly compared. The wind speed and direction are calculated from the differences in the times of flight along each axis. This calculation is independent of environmental factors such as temperature.

Specifications

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

Kipp and Zonen Pyranometer Model CM6B

The CM6B pyranometer is intended for routine global solar radiation measurement research on a level surface. The CM6B features a sixty-four thermocouple junction (series connected) sensing element. The sensing element is coated with a highly stable carbon based non-organic coating, which delivers excellent spectral absorption and long term stability characteristics. The sensing element is housed under two concentric fitting Schott K5 glass domes.

Specifications

RRS James Cook JC156 Meteorology Instrumentation

Instrumentation

The meteorological suite of sensors was located on the forecastle deck, at approximately 17.1 m above sea level. The anemometer orientation was 0° on the bow.

Skye Instruments PAR Energy Sensor Model SKE 510

The SKE 510 is suitable for measuring photosynthetically active radiation (PAR) from natural or artificial light sources. The sensor is fully waterproof and guaranteed submersible to 4m depth, and indoor versions are also available.

The instrument uses a blue-enhanced planar diffused silicon detector to measure energy (in W m^-2) over the 400-700 nm waveband. It has a cosine-corrected head and a square spectral response. The sensor can operate over a temperature range of -35 to 70 °C and a humidity range of 0-100% RH.

Specifications

Vaisala PTB110 barometer

An industrial, analog barometer which uses a silicon capacitive sensor (BAROCAP). The sensor produces either frequency or voltage output and is mountable on a (35 mm wide) DIN rail.

Operating ranges (1 hPa = 1 mbar)

General

Accuracy

* Defined as ±2 standard deviation limits of end-point non-linearity, hysteresis error or repeatability error.
** Defined as ±2 standard deviation limits of inaccuracy of the working standard including traceability to NIST.
*** Defined as the root sum of the squares (RSS) of end-point non-linearity, hysteresis error, repeatability error and calibration uncertainty at room temperature when using voltage output.

More detailed information can be found in the manufacturer's data sheet and user's guide.

Vaisala Temperature and Relative Humidity HMP Sensors

A family of sensors and instruments (sensors plus integral displays or loggers) for the measurement of air temperature and relative humidity. All are based on a probe containing a patent (HUMICAP) capacitive thin polymer film capacitanece humidity sensor and a Pt100 platinum resistance thermometer. The probes are available with a wide range of packaging, cabling and interface options all of which have designations of the form HMPnn or HMPnnn such as HMP45 and HMP230. Vaisala sensors are incorporated into weather stations and marketed by Campbell Scientific.

All versions operate at up to 100% humidity. Operating temperature ranges vary between models, allowing users to select the version best suited to their requirements.

Further details can be found in the manufacturer's specification sheets for the HMP 45 series, HMP 70 series and HMP 230 series.

RRS James Cook JC156 Meteorology Data Processing Procedures

Originator's Data Processing

The data were logged by the TECHSAS (TECHnical and Scientific sensors Acquisition System) data logging system into daily NetCDF files which were provided to BODC for processing. Data was additionally logged into the RVS Level-C format which have been archived at BODC.

Files delivered to BODC

BODC Data Processing

The data were reformatted to BODC internal format using standard banking procedures. Data were averaged at 60 second intervals. The following table shows how variables within the file were mapped to appropriate BODC parameter codes:

yyyymmdd-000000-MET-SURFMET.SURFMETv2

yyyymmdd-000000-Light-SURFMET.SURFMETv2

All data expressed at measurement altitude.

Calibrations

Field Calibrations

No field calibrations were applied to the data at BODC.

Manufacturers Calibrations

PAR/TIR

The following manufacturer's calibrations were applied to the PAR and TIR light sensors using:

y (W m ^-2 ) = (a x 10 ⁶ )/b

where 'a' is the raw data in volts and 'b' is the calibration offset (µV per W m ^-2 ) as shown below.

All the reformatted data were visualised using the in-house EDSERPLO software. Suspect data were marked by adding an appropriate quality control flag.

Absolute wind speed and direction

Relative wind speed and direction were corrected for the ship's heading and speed using the POS MV gyro heading, ship velocities (calculated at BODC from the main positional channels) and an anemometer orientation of 0° on the bow, thus obtaining the BODC derived absolute wind speed and direction parameters, with codes EWSBSS01 and EWDASS01 respectively.

Air pressure

A manufacturer's calibration was not applied to the barometer because there was no significant offset reported on the certified calibration certificate.

Air temperature and humidity

Manufacturer's calibrations were not applied to the temperature and humidity probe because there were no significant offsets reported on the certified calibration certificate.

Project Information

FRidge: The impact of Mid-Ocean Ridges on the Ocean's Iron cycle

FRidge is a research project funded by the UK Natural Environment Research Council (NERC). It aims to explore hypotheses regarding the mechanisms that shape ocean iron distribution and in particular, the role of hydrothermal inputs from distinct vent sites along the Mid-Atlantic Ridge.

The project is part of the UK contribution to the international GEOTRACES programme. Research will take place along the GEOTRACES International Section GA13.

Introduction

Photosynthesis by marine phytoplankton contributes to the partitioning of carbon dioxide between the atmosphere and the ocean. Iron is essential for phytoplankton growth as it is required for a number of important enzymes that participate in both photosynthesis and respiration. Mid-ocean ridges are significant sources of iron to the ocean due to hydrothermal activity, with dramatic iron plumes that persist for thousands of kilometres away from the ridge.

The impact of hydrothermal iron on the ocean carbon cycle depends both on the longevity of the iron plumes and the mixing of iron into surface waters, with both aspects poorly constrained. Thus our understanding of how the ocean iron cycle functions is incomplete. This is important as the influence of ocean biology on ocean-atmosphere carbon dioxide exchanges via the biological pump is controlled by iron availability over large parts of the ocean.

Scientific Objectives

The main objectives of the project are to:

1. Document the changes in iron supply, cycling and speciation along the diverse hydrothermal systems of the northern Mid-Atlantic Ridge.

2. Link observational science with state of the art ocean modelling to assess the global influence of mid-ocean ridges on the ocean iron cycle and the sustenance of surface productivity.

To deliver on these objectives, a research expedition to the Atlantic Ocean was carried out to measure trace metals, nutrients and ocean physics over and around the Mid-Atlantic Ridge. Ultimately this will be able to address the broader question of how the amount of iron from mid-ocean ridges can influence phytoplankton growth in the open ocean.

Fieldwork

The FRidge cruise was completed aboard RRS James Cook cruise JC156, which ran between Southampton and Guadeloupe from the 20th of December 2017 to the 1st of February 2018. See the table below for details on what was sampled:

The above images show the locations of known hydrothermal vent systems and the dots represent locations where sampling took place.

Project Collaborators

The science delivered as part of this GEOTRACES section is greatly enhanced by the collaboration with a number of scientists from the following institutions:

- University of Southampton

- University of Liverpool

- Plymouth Marine Laboratory

- Oxford University

- University of South Florida

- University of Washington

- University of California Santa Barbara

- Woods Hole Oceanographic Institute

Scientific Personnel

- Alessandro Tagliabue (Cruise Chief Scientist, University of Liverpool, UK)

- Maeve Lohan (University of Southampton, UK)

- Andy Heath (University of Liverpool, UK)

- Alastair Lough (University of Southampton, UK)

- Shaun Rigby (University of Liverpool, UK)

Project Partners

- Alex Baker (University of East Anglia)

- William Jenkins (Woods Hole Oceanographic Institute)

- Brandy Toner (University of Minnesota)

Funding

This is a NERC funded research project. Funding was provided in the form of two fellowship and training grants.Total value of £527,588. The lead/parent grant reference number is NE/N010396/1 led by Maeve Lohan and the child grant NE/N009525/1 is led by Alessandro Tagliabue.

Period of Award: 4 Sep 2017 - 3 Mar 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: