Metadata Report for BODC Series Reference Number 1795334
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
Data Description |
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Time Co-ordinates(UT) |
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Spatial Co-ordinates | |||||||||||||||||||||||||||||||||
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Parameters |
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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
Instrument Description
CTD Carousel multi sampling (CTD-CMS)
The CTD-CMS system, attached to the end of a titanium armored cable (8mm o.d.) from the No.2 winch of R.V. Hakuho Maru, consisted of a SBE911plus system with a 24 Niskin-X bottle capacity. This was controlled by a CTD Deck Unit connected to a WINDOWS desktop computer. The CTD unit was switched during stations BD-4 and BD-12 to a unit suitable for depths up to 10000m. During these casts, no additional sensors were used.
All the zinc anodes on the Carousel frames (except for those on the CTD housings) were replaced by aluminum anodes, in order to avoid Zn contamination.
Further details on the CTD-CMS system can be found on page 25 of thecruise report
The system was fitted with the following additional sensors:
Sensor | Model | Serial number | Calibration date | Comments |
---|---|---|---|---|
Pressure | Digiquartz Paroscientific (6000m) | Unknown | Precise date unknown, calibrated pre-cruise by Sea-Bird Scientific Inc. | Stations 1-3, 5-11, 13-22 |
Pressure | Digiquartz Paroscientific (10000m) | Unknown | Precise date unknown, calibrated pre-cruise by Sea-Bird Scientific Inc. | Stations 4 and 12 |
Conductivity sensor | SBE 4C | Unknown | Precise date unknown, calibrated pre-cruise by Sea-Bird Scientific Inc. | - |
Temperature sensor | SBE 3plus | Unknown | Precise date unknown, calibrated pre-cruise by Sea-Bird Scientific Inc. | - |
Dissolved oxygen | SBE 43 | Unknown | Precise date unknown, calibrated pre-cruise by Sea-Bird Scientific Inc. Not calibrated against independent water samples onboard. | Stations 1-3, 5-11, 13-22 |
Fluorometer | Chelsea Aquatracka MK III | Unknown | Precise date unknown, calibrated pre-cruise by Chelsea Technologies Group Ltd. Not calibrated against independent water samples onboard. | Stations 1-3, 5-11, 13-22 |
CDOM sesor | Wetlabs ECO-FL Fluorometer | 2435 | Unknown | Stations 1-3, 5-11, 13-22 |
Turbidity meter | SeaPoint Turbidity Meter | Unknown | Unknown | Stations 1-3, 5-11, 13-22 |
Pinger | Benthos 2216 Deep Sea pinger | Unknown | Unknown | - |
Altimeter | Benthos PSA-916T Sonar Altimeter | Unknown | Unknown | Station 12 only |
Sea-Bird Electronics SBE 911 and SBE 917 series CTD profilers
The SBE 911 and SBE 917 series of conductivity-temperature-depth (CTD) units are used to collect hydrographic profiles, including temperature, conductivity and pressure as standard. Each profiler consists of an underwater unit and deck unit or SEARAM. Auxiliary sensors, such as fluorometers, dissolved oxygen sensors and transmissometers, and carousel water samplers are commonly added to the underwater unit.
Underwater unit
The CTD underwater unit (SBE 9 or SBE 9 plus) comprises a protective cage (usually with a carousel water sampler), including a main pressure housing containing power supplies, acquisition electronics, telemetry circuitry, and a suite of modular sensors. The original SBE 9 incorporated Sea-Bird's standard modular SBE 3 temperature sensor and SBE 4 conductivity sensor, and a Paroscientific Digiquartz pressure sensor. The conductivity cell was connected to a pump-fed plastic tubing circuit that could include auxiliary sensors. Each SBE 9 unit was custom built to individual specification. The SBE 9 was replaced in 1997 by an off-the-shelf version, termed the SBE 9 plus, that incorporated the SBE 3 plus (or SBE 3P) temperature sensor, SBE 4C conductivity sensor and a Paroscientific Digiquartz pressure sensor. Sensors could be connected to a pump-fed plastic tubing circuit or stand-alone.
Temperature, conductivity and pressure sensors
The conductivity, temperature, and pressure sensors supplied with Sea-Bird CTD systems have outputs in the form of variable frequencies, which are measured using high-speed parallel counters. The resulting count totals are converted to numeric representations of the original frequencies, which bear a direct relationship to temperature, conductivity or pressure. Sampling frequencies for these sensors are typically set at 24 Hz.
The temperature sensing element is a glass-coated thermistor bead, pressure-protected inside a stainless steel tube, while the conductivity sensing element is a cylindrical, flow-through, borosilicate glass cell with three internal platinum electrodes. Thermistor resistance or conductivity cell resistance, respectively, is the controlling element in an optimized Wien Bridge oscillator circuit, which produces a frequency output that can be converted to a temperature or conductivity reading. These sensors are available with depth ratings of 6800 m (aluminium housing) or 10500 m (titanium housing). The Paroscientific Digiquartz pressure sensor comprises a quartz crystal resonator that responds to pressure-induced stress, and temperature is measured for thermal compensation of the calculated pressure.
Additional sensors
Optional sensors for dissolved oxygen, pH, light transmission, fluorescence and others do not require the very high levels of resolution needed in the primary CTD channels, nor do these sensors generally offer variable frequency outputs. Accordingly, signals from the auxiliary sensors are acquired using a conventional voltage-input multiplexed A/D converter (optional). Some Sea-Bird CTDs use a strain gauge pressure sensor (Senso-Metrics) in which case their pressure output data is in the same form as that from the auxiliary sensors as described above.
Deck unit or SEARAM
Each underwater unit is connected to a power supply and data logging system: the SBE 11 (or SBE 11 plus) deck unit allows real-time interfacing between the deck and the underwater unit via a conductive wire, while the submersible SBE 17 (or SBE 17 plus) SEARAM plugs directly into the underwater unit and data are downloaded on recovery of the CTD. The combination of SBE 9 and SBE 17 or SBE 11 are termed SBE 917 or SBE 911, respectively, while the combinations of SBE 9 plus and SBE 17 plus or SBE 11 plus are termed SBE 917 plus or SBE 911 plus.
Specifications
Specifications for the SBE 9 plus underwater unit are listed below:
Parameter | Range | Initial accuracy | Resolution at 24 Hz | Response time |
---|---|---|---|---|
Temperature | -5 to 35°C | 0.001°C | 0.0002°C | 0.065 sec |
Conductivity | 0 to 7 S m-1 | 0.0003 S m-1 | 0.00004 S m-1 | 0.065 sec (pumped) |
Pressure | 0 to full scale (1400, 2000, 4200, 6800 or 10500 m) | 0.015% of full scale | 0.001% of full scale | 0.015 sec |
Further details can be found in the manufacturer's specification sheet.
BODC Processing
Reformatting
The data from KH12-4 arrived at BODC as 22 xlsx files which were reformatted to .csv in the first instance. Data were subsequently reformatted to BODC internal QXF format. The following table shows how the variables within the .csv files were mapped to the appropriate BODC parameter codes.
Originator's Parameter Name | Units | Description | BODC Parameter Code | Units | Comments |
---|---|---|---|---|---|
PrDM | dbar | Pressure (spatial co-ordinate) exerted by the water body by profiling pressure sensor and corrected to read zero at sea level | PRESPR01 | dbar | Calibrated before cruise by Sea-Bird Electronics Inc. but no dates given. |
T090C | °C | Temperature of the water body by CTD or STD | TEMPST01 | °C | Calibrated before cruise by Sea-Bird Electronics Inc. but no dates given |
C0S/m | S/m | Electrical conductivity of the water body by CTD | CNDCST01 | S/m | Calibrated before cruise by Sea-Bird Electronics Inc. but no dates given. No calibration against independant water samples. |
Sbeox0ML/L | ml l-1 | Concentration of oxygen per unit volume of the water body by Sea-Bird SBE 43 sensor and no calibration against sample data | DOXYSU01 | µmol l-1 | Calibrated before cruise by Sea-Bird Electronics Inc. but date unknown. No calibration against independant water samples. Values multipled by 44.66 for unit conversion to µmol l-1. Used on all casts except BD-4 and BD-12. |
FlSP | µg l-1 | Concentration of chlorophyll-a per unit volume of the water body by in-situ chlorophyll fluorometer | CPHLPR01 | mg m-3 | Calibrated before cruise by Chelsea Technologies Group Ltd. but date unknown. Used on all casts except BD-4 and BD-12. |
Upoly0 | ppb | Concentration of coloured dissolved organic matter per unit volume of the water body by fluorometry | CDOMZZ01 | ppb | Used on all casts except BD-4 and BD-12. |
SeaTurbMtr | FTU | Turbidity of the water body by in-situ optical backscatter measurement and laboratory calibration against formazin | TURBPR01 | NTU | Used on all casts except BD-4 and BD-12. |
AltM | Metres | Height above bed in the water body | AHSFZZ01 | Metres | Used only on station BD-12 |
SvDM | Metres per second | Sound velocity in the water body | SVELXXXX | Metres per second | Used on all casts except BD-4 and BD-12. Derived from temperature and salinity by originator. |
Sal00 | Dimensionless | Practical salinity of the water body by CTD and computation using UNESCO 1983 algorithm and NO calibration against independent measurements | PSALCU01 | Dimensionless | No calibration against independent water samples. |
Sigma-t00 | kg m-3 | Sigma-theta of the water body by CTD and computation from salinity and potential temperature using UNESCO algorithm | SIGTPR01 | kg m-3 | Derived parameter - not transferred. |
Potemp090C | °C | Potential temperature of the water body by computation using UNESCO 1983 algorithm | POTMCV01 | °C | Derived parameter - not transferred. |
BODC assigned each CTD event with a unique identifier (OID) based on the originator's event log. OID was assembled from the originator's station number.
Screening
Reformatted CTD data were visualised using the in-house graphical editor EDSERPLO. Quality control flags were applied to data as necessary.
Originator's Data Processing
Sampling Strategy
During the cruise two different CTD-systems were deployed.
- An SBE911plus CTD-system suitable for depths up to 6000m (20 stations).
- An SBE911plus CTD-system suitable for depths greater than 6000m, up to 10000m (2 stations)
A total of 22 casts were carried out during the cruise.
The CTD Carousel sampling (CTD-CMS) System
To avoid contamination, the frame and cable of the CTD-CMS system was made of titanium , and all zinc anodes on the Carousel frames (except for those on the CTD housings) were replaced by aluminum anodes, in order to avoid Zn contamination. Water samples were taken by triggering the Niskin-X bottles at appropriate depths while the system was coming up to the surface. The deepest sample was usually taken at a depth of approximately 10 meters above the bottom.
To further reduce contamination for the sampling, Niskin-X bottles were cleaned before the cruise by filling the bottles with 1.5% Extran MA01 (1 day), 0.1M HCl (pH=1, 1day), and Milli-Q water (more than 2 days), successively. Teflon spigots were pre-washed by soaking in 1% of Extran MA02 (1 day) and 1M HCl(1 day), and cleaned by heating in conc.HClO4:conc.H2SO4:conc.HNO3=1:1:1 mixture (120°C, 3 hrs), 6M HCl 25 (120°C, 3 hrs), and Milli-Q water (100°C, 3 hrs), successively. Viton O-rings were pre-washed by soaking in 1% of Extran MA02 (1 day) and 0.1M HCl (1 day), and cleaned by heating in 0.1M HCl (at 60°C, 12hrs), and Milli-Q water (at 68°C, 12 hrs).
Data Processing
There is no information available regarding the processing of the CTD sensors, except that the data were produced using Sea-Bird Electronics Inc. 'SEASOFT' software.
Field Calibrations
None of the CTD sensors were calibrated against independent water samples from the Niskin bottles.
Further details on the originators processing can be found in the cruise report.
Project Information
GEOTRACES
Introduction
GEOTRACES is an international programme sponsored by SCOR which aims to improve our understanding of biogeochemical cycles and large-scale distribution of trace elements and their isotopes (TEIs) in the marine environment. The global field programme started in 2009 and will run for at least a decade. Before the official launch of GEOTRACES, fieldwork was carried out as part of the International Polar Year (IPY)(2007-2009) where 14 cruises were connected to GEOTRACES.
GEOTRACES is expected to become the largest programme to focus on the chemistry of the oceans and will improve our understanding of past, present and future distributions of TEIs and their relationships to important global processes.
This initiative was prompted by the increasing recognition that TEIs are playing a crucial role as regulators and recorders of important biogeochemical and physical processes that control the structure and productivity of marine ecosystems, the dispersion of contaminants in the marine environment, the level of greenhouse gases in the atmosphere, and global climate.
Scientific Objectives
GEOTRACES mission is: To identify processes and quantify fluxes that control the distribution of key trace elements and isotopes in the ocean, and to establish the sensitivity of these distributions to changing environmental conditions.
Three overriding goals support the GEOTRACES mission
- Determine ocean distributions of selected TEIs at all major ocean basins
- Evaluate the sources, sinks, and internal cycling of these TEIs and thereby characterize more completely their global biogeochemical cycles
- Provide a baseline distribution in the Polar Regions as reference for assessing past and future changes.
These goals will be pursued through complementary research strategies, including observations, experiments and modelling.
Fieldwork
The central component of GEOTRACES fieldwork will be a series of cruises spanning all Ocean basins see map below.
Three types of cruise are required to meet the goals set out by GEOTRACES. These are
- Section cruises - These will measure all the key parameters (see below) over the full depth of the water column. The sections were discussed and approved by the International GEOTRACES Scientific Steering Committee at the basin workshops.
- Process Studies - These will investigate a particular process relevant to the cycling of trace metal and isotopes. They must follow the "Criteria for Establishing GEOTRACES Process Studies" and be approved by the International GEOTRACES Scientific Steering Committee.
- Cruises collecting GEOTRACES compliant data - These will collect some trace element or isotope data. They must follow the GEOTRACES Intercalibration and Data Management protocols
IPY-GEOTRACES
The IPY-GEOTRACES programme comprised of 14 research cruises on ships from 7 nations; Australia, Canada, France, Germany, New Zealand, Japan and Russia. The cruises will not be classified in the same way as the full GEOTRACES programme since the intercalibration protocols and data management protocols had not been established before the start of the IPY. But IPY-GEOTRACES data will still be quality controlled by GDAC and in the majority of cases verified versus Intercalibration standards or protocols.
Key parameters
The key parameters as set out by the GEOTRACES science plan are as follows: Fe, Al, Zn, Mn, Cd, Cu; 15N, 13C; 230Th, 231Pa; Pb isotopes, Nd isotopes; stored sample, particles, aerosols.
Weblink:
http://www.bodc.ac.uk/geotraces/
http://www.geotraces.org/
Data Activity or Cruise Information
Cruise
Cruise Name | KH12-04 (GP02) |
Departure Date | 2012-08-23 |
Arrival Date | 2012-10-03 |
Principal Scientist(s) | Toshitaka Gamo (University of Tokyo, Atmosphere and Ocean Research Institute) |
Ship | Hakuho Maru |
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 |