Metadata Report for BODC Series Reference Number 1197278

• 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 (JC079) AMT22 FRRF Data Quality Report

Data Quality Report

The FRRF instruments were changed on the 24 October 2012.

Values marked -999 in the originator's data files have been converted to the appropriate absent data values using the flag 'N'.

Functional Absorption cross-section (light and dark)

(0-1600 A²Q^-1)for these parameters have been flagged as suspect.

Photochemical efficiency {Fv/Fm}

Values outside the expected range of values (0-1) for these parameters have been flagged as suspect.

In-vivo fluorescence (chlorophyll)

Values outside the expected range of values (0-5) for these parameters have been flagged as suspect.

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

Chelsea Technologies Group FASTtracka MKI FRRF

The FASTtracka is a Fast Repetition Rate Fluorometer (FRRF) designed to measure the variable fluorescence of marine phytoplankton. It can be deployed on its own or integrated in moorings, profiling systems or in towed applications.

The operation mode comprises a rapid series of high frequency flashes (200 kHz), which enable the measurement of the absorption cross section of photosystem II (PSII), the rate of electron transport and the level of photochemical quenching. A 16 MHz clock microcontroller monitors the digital acquisition of the stimulated fluorescence and the excitation flashes, while simultaneously measuring Photosynthetic Active Radiation (PAR). These concurrent measurements allow for estimates of phytoplankton primary productivity to be made.

A comparison of ambient-irradiated and dark adapted phytoplankton samples is possible due to the optical head dual (light and dark) chamber design. All measurements are stored on an internal memory card with a 24 MB capacity and are downloaded through an RS232 connector.

Additional specifications include a maximum depth rating of 500 m and a chlorophyll-a sensitivity of 0.1 to 30 µg l^-1.

Further information can be found in the manufacturer's specification sheet or the user guide.

RRS James Cook (JC079) AMT22 FRRF Sensor Profile Instrumentation II

24th October 2012 to 19th November 2012

AMT22 (JC079) Bio-Optics - Fast Repetition Rate Fluorometer (FRRF) profiles

Data Acquisition and Analysis

These data originate from analysis of profiles collected from the FRRF sensor deployed on the optics rig on RRS James Cook between 10th October and 24th November 2012. Optics profiles were made at or within one hour of local solar noon and mostly deployed on the sunward side of the ship. Upon recovery, data from the FRRF were downloaded using hyperterminal.

The FRRF data were processed using V6 of the Sam Laney (WHOI) Matlab code as used in previous AMT cruises. This required the FRRF to be characterised using 0.2 µm filtered water, at each of the gain settings (0, 1, 4, 16, 64, 256) for both the light and dark chambers, in a black bucket. During this cruise there were difficulties using Sam Laney's code. In addition to this the Chelsea Technologies Group (CTG) FastTracka MK I Fluorometer was swapped with a different (CTG) FastTracka MK I sensor on the 24th October 2012.

The primary outputs of the FRRF data stream are the maximum fluorescence (Fm) and the ratio of the variable to maximum fluorescence (Fv/Fm). The final FRRF data product will consists of the phytoplankton physiological parameters binned to 2 m depth resolution.

BODC Data Processing Procedures

Data were submitted to BODC in 38 .csv files and saved to the archive with accession number PML140007. The files were provided to BODC with the following metadata: cruise, date, Julian Day, latitude and longitude. The light/dark Photosynthetically Active Range (PAR) channels were not loaded as these channels have been loaded to the database with the UV and AC9 profiles. The light/dark chamber turnover time for electron flow (tau) and light/dark chamber gain settings were not loaded to the database but are available upon request.

Parameter codes defined in BODC parameter dictionary were assigned to the variables as shown in the table below. No unit conversions were necessary as all the parameters were provided with the same units as the BODC Parameter Dictionary.

Project Information

No Project Information held for the Series

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: