Metadata Report for BODC Series Reference Number 341832
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
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Problem Reports
No Problem Report Found in the Database
Data Access Policy
Public domain 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.
The recommended acknowledgment is
"This study uses data from the data source/organisation/programme, provided by the British Oceanographic Data Centre and funded by the funding body."
Narrative Documents
Neil Brown MK3 CTD
The Neil Brown MK3 conductivity-temperature-depth (CTD) profiler consists of an integral unit containing pressure, temperature and conductivity sensors with an optional dissolved oxygen sensor in a pressure-hardened casing. The most widely used variant in the 1980s and 1990s was the MK3B. An upgrade to this, the MK3C, was developed to meet the requirements of the WOCE project.
The MK3C includes a low hysteresis, titanium strain gauge pressure transducer. The transducer temperature is measured separately, allowing correction for the effects of temperature on pressure measurements. The MK3C conductivity cell features a free flow, internal field design that eliminates ducted pumping and is not affected by external metallic objects such as guard cages and external sensors.
Additional optional sensors include pH and a pressure-temperature fluorometer. The instrument is no longer in production, but is supported (repair and calibration) by General Oceanics.
Specifications
These specification apply to the MK3C version.
| Pressure | Temperature | Conductivity | |
| Range | 6500 m 3200 m (optional) | -3 to 32°C | 1 to 6.5 S cm-1 |
| Accuracy | 0.0015% FS 0.03% FS < 1 msec | 0.0005°C 0.003°C < 30 msec | 0.0001 S cm-1 0.0003 S cm-1 < 30 msec |
Further details can be found in the specification sheet.
RV Ignat Pavlyuchenkov (Oct-Nov 1991) CTD Data Documentation
Introduction
Documentation for the CTD data collected on RV Ignat Pavlyuchenkov (October - November 1991) by the School of Ocean Sciences, University of Wales, Bangor, under the direction of E.D. Barton.
This cruise formed part of EU MAST Project 0031 - European Coastal Transition Zone, Islas Canarias, with partners from the University of Wales, Bangor, UK, Universidad de Las Palmas de Gran Canarias, Spain, Centro Oceanografico de Canarias, Spain and Centro Comune di Ricerca, Ispra, Italy.
Instrumentation
Throughout the cruise period most of the equipment performed well and only minor problems occurred. The only major difficulty was in relation to the CTD which was initially being used (known as the 'Russian CTD'); the conductivity sensor of which was accidentally damaged. Thus, the entire CTD system was replaced by the one taken aboard as part of the University of Wales, Bangor/ Research Vessel Services (UWB/RVS). The equipment of the 'Russian' and 'UWB/ RVS' CTD systems was comparable. Both included Neil Brown CTD Mark III units, fluorometer (Sea-Tech 57S and Chelsea Instruments respectively), 25cm Sea-Tech transmissometer, and a Rosette sampler of 24 bottles and 12 bottles. Data in both cases were logged using EG&G software running under MS-DOS and IBM type personal computers.
Calibration and Data Quality
In order to calibrate the different sensors of the two CTD systems used through the cruise, water samples and temperature readings were routinely taken during most of the CTD casts.
Conductivity
To achieve the calibration of the conductivity sensors, the water samples were analysed on the salinometer brought aboard as part of the equipment of the Spanish Institute of Oceanography (IEO), and the difference between the two sources of data (i.e. the data measured by the CTD minus the data from the salinometer) was calculated.
Temperature
Similarly, in order to calibrate the temperature sensors the difference between the CTD and revering thermometers was also estimated.
The calibration curves of both parameters were then updated.
Following application of the calibration, each profile of temperature and salinity was iteratively displayed and corrected if necessary. As a first error inspection, artificial structures (i.e. isolated spikes) were removed and linear interpolation used to correct the profiles.
Chlorophyll
The Sea-Tech 57S fluorometer is a linear response instrument. The Chelsea Instruments Mark II Aquatracka is a logarithmic response instrument. Data derived from this instrument were comparatively noisy and were smoothed with a 7 point running average filter to remove the larger spikes and oscillations. Samples for fluorometer calibration were taken at known depths within several CTD and fluorescence profiles, using the Rosette bottles. Typical sampling depths include deep water, the chlorophyll-a maximum and the surface mixed layer. The bottle samples were analysed using a Turner bench fluorometer and the concentration of chlorophyll-a and phaeopigments calculated.
Sample concentrations of chlorophyll-a were plotted against their fluorescence voltage, measured on the corresponding profiling fluorometer. A linear regression analysis was performed on the Sea-Tech instrument data, whilst a non-linear curve fitting program was employed to establish the Chelsea Instruments Aquatracka calibration. These relationships were then used to convert all the fluorescence profiles to profiles of pigment concentration.
The following equations were used to convert the fluorometer voltages to predicted chlorophyll-a concentrations in mg/m3:
Sea-Tech fluorometer
fluorescence voltage = (3.67 x chlorophyll concentration) + 0.24
Chelsea Instruments Aquatracka fluorometer
fluorescence voltage = 2log ((2.90 x chlorophyll concentration) + 1) + 0.66
References
Velez-Munoz, H.S. October 1992.
Ignat Pavlyuchenkov Cruise Report: Hydrographic Field. European Coastal Transition Zone Islas Canarias, MAST Project 0031. Report 0031-09
Wild, K.A. May 1992.
Ignat Pavlyuchenkov Cruise Report: General and Phytoplankton Biomass. European Coastal Transition Zone Islas Canarias, MAST Project 0031. Report 0031-08
Project Information
European Coastal Transition Zone (ECTZ)
The European Coastal Transition Zone, Islas Canarias, (EU MAST Project 0031) was undertaken to improve understanding of physical and biological phenomena in the region of the Canary Islands, which are located at the transition zone between the eutrophic upwelling waters of the African continental shelf and the oligotrophic oceanic waters of the Canary Current.
Data Activity or Cruise Information
Cruise
| Cruise Name | IP 9/91 |
| Departure Date | 1991-10-17 |
| Arrival Date | 1991-11-05 |
| Principal Scientist(s) | |
| Ship | Ignat Pavlyuchenkov |
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:
| Flag | Description |
|---|---|
| Blank | Unqualified |
| < | Below detection limit |
| > | In excess of quoted value |
| A | Taxonomic flag for affinis (aff.) |
| B | Beginning of CTD Down/Up Cast |
| C | Taxonomic flag for confer (cf.) |
| D | Thermometric depth |
| E | End of CTD Down/Up Cast |
| G | Non-taxonomic biological characteristic uncertainty |
| H | Extrapolated value |
| I | Taxonomic flag for single species (sp.) |
| K | Improbable value - unknown quality control source |
| L | Improbable value - originator's quality control |
| M | Improbable value - BODC quality control |
| N | Null value |
| O | Improbable value - user quality control |
| P | Trace/calm |
| Q | Indeterminate |
| R | Replacement value |
| S | Estimated value |
| T | Interpolated value |
| U | Uncalibrated |
| W | Control value |
| X | Excessive difference |
SeaDataNet Quality Control Flags
The following single character qualifying flags may be associated with one or more individual parameters with a data cycle:
| Flag | Description |
|---|---|
| 0 | no quality control |
| 1 | good value |
| 2 | probably good value |
| 3 | probably bad value |
| 4 | bad value |
| 5 | changed value |
| 6 | value below detection |
| 7 | value in excess |
| 8 | interpolated value |
| 9 | missing value |
| A | value phenomenon uncertain |
| B | nominal value |
| Q | value below limit of quantification |
