Metadata Report for BODC Series Reference Number 2207635
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
Open 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.
If the Information Provider does not provide a specific attribution statement, or if you are using Information from several Information Providers and multiple attributions are not practical in your product or application, you may consider using the following:
"Contains public sector information licensed under the Open Government Licence v1.0."
Narrative Documents
RRS James Cook Cruise JC064 Underway Document
Cruise details
| Dates | 10th Sept. 2011 to 9th Oct. 2011 |
|---|---|
| Principal Scientific Officer | Dr Stuart Cunningham (NOCS) |
JC064 formed the second leg of the cruise, while JC063 was referred to as the first. The JC064 cruise departed on 10 September 2011 from Santa Cruz de Tenerife and arrived again in Santa Cruz de Tenerife on 9 October 2011 where the cruise terminated. The purpose of the cruise was to refurbish a mooring array on the Mid-Atlantic Ridge and at the Easter Boundary of the Atlantic near the Moroccan Coast at a nominal latitude of 26.5°N. The moorings are part of the RAPIDMOC mooring array, monitoring the Atlantic Meridional Overturning Circulation and Heat Flux.
SeaBird Digital Oceanographic Thermometer SBE38
The SBE38 is an ultra-stable thermistor that can be integrated as a remote temperature sensor with an SBE21 Thermosalinograph or an SBE 45 Micro TSG, or as a secondary temperature sensor with an SBE 16 plus, 16plus-IM, 16plus V2, 16plus-IM V2 or 19plus V2 SEACAT CTD.
Temperature is determined by applying an AC excitation to reference resistances and an ultra-stable aged thermistor. The reference resistor is a hermetically sealed VISHAY. AC excitation and ratiometric comparison using a common processing channel removes measurement errors due to parasitic thermocouples, offset voltages, leakage currents and gain errors.
The SBE38 can operate in polled sampling, where it takes one sample and transmits the data, or in continuous sampling.
Specifications
| Depth rating | up to 10500 m |
| Temperature range | -5 to 35°C |
| Initial accuracy | ± 0.001°C |
| Resolution | 0.00025°C |
| Stability | 0.001°C in 6 months |
| Response time | 500 ms |
| Self-heating error | < 200 µK |
Further details can be found in the manufacturer's specification sheet.
WET Labs WETStar Fluorometers
WET Labs WETStar fluorometers are miniature flow-through fluorometers, designed to measure relative concentrations of chlorophyll, CDOM, uranine, rhodamineWT dye, or phycoerythrin pigment in a sample of water. The sample is pumped through a quartz tube, and excited by a light source tuned to the fluorescence characteristics of the object substance. A photodiode detector measures the portion of the excitation energy that is emitted as fluorescence.
Specifications
By model:
| Chlorophyll WETStar | CDOM WETStar | Uranine WETStar | Rhodamine WETStar | Phycoerythrin WETStar | |
|---|---|---|---|---|---|
| Excitation wavelength | 460 nm | 370 nm | 485 nm | 470 nm | 525 nm |
| Emission wavelength | 695 nm | 460 nm | 530 nm | 590 nm | 575 nm |
| Sensitivity | 0.03 µg l-1 | 0.100 ppb QSD | 1 µg l-1 | - | - |
| Range | 0.03-75 µg l-1 | 0-100 ppb; 0-250 ppb | 0-4000 µg l-1 | - | - |
All models:
| Temperature range | 0-30°C |
|---|---|
| Depth rating | 600 m |
| Response time | 0.17 s analogue; 0.125 s digital |
| Output | 0-5 VDC analogue; 0-4095 counts digital |
Further details can be found in the manufacturer's specification sheet, and in the instrument manual.
WETLabs C-Star transmissometer
This instrument is designed to measure beam transmittance by submersion or with an optional flow tube for pumped applications. It can be used in profiles, moorings or as part of an underway system.
Two models are available, a 25 cm pathlength, which can be built in aluminum or co-polymer, and a 10 cm pathlength with a plastic housing. Both have an analog output, but a digital model is also available.
This instrument has been updated to provide a high resolution RS232 data output, while maintaining the same design and characteristics.
Specifications
| Pathlength | 10 or 25 cm |
| Wavelength | 370, 470, 530 or 660 nm |
| Bandwidth | ~ 20 nm for wavelengths of 470, 530 and 660 nm ~ 10 to 12 nm for a wavelength of 370 nm |
| Temperature error | 0.02 % full scale °C-1 |
| Temperature range | 0 to 30°C |
| Rated depth | 600 m (plastic housing) 6000 m (aluminum housing) |
Further details are available in the manufacturer's specification sheet or user guide.
RRS James Cook Cruise JC064 Surface Hydrography Instrumentation
The instruments used to collect this data set are presented in the table below:
| Sensor | Serial number | Last calibration date |
|---|---|---|
| Sea-Bird SBE 45 MicroTSG | 0233 | 19/07/2011 |
| Sea-Bird SBE 38 digital thermometer | 3853440-0475 | 15/03/2011 |
| Wetlabs C-star transmissometer | CST-1132PR | 25/07/2011 |
| Wetlabs fluorometer | WS3S-246 | 09/08/2011 |
Near surface temperature was measured with a SBE 38 probe, located in the inlet of the ship, measuring the temperature of water 5.5 metres below the sea surface.
A SBE45 MicroTSG is fitted in the wet lab and the non-toxic supply runs from this intake. Samples were taken every four hours from the non-toxic supply on the upstream side of the SBE 45 in order to calibrate the conductivity data.
SeaBird MicroTSG Thermosalinograph SBE 45
The SBE45 MicroTSG is an externally powered instrument designed for shipboard measurement of temperature and conductivity of pumped near-surface water samples. The instrument can also compute salinity and sound velocity internally.
The MicroTSG comprises a platinum-electrode glass conductivity cell and a stable, pressure-protected thermistor temperature sensor. It also contains an RS-232 port for appending the output of a remote temperature sensor, allowing for direct measurement of sea surface temperature.
The instrument can operate in Polled, Autonomous and Serial Line Sync sampling modes:
- Polled sampling: the instrument takes one sample on command
- Autonomous sampling: the instrument samples at preprogrammed intervals and does not enter quiescence (sleep) state between samples
- Serial Line Sync: a pulse on the serial line causes the instrument to wake up, sample and re-enter quiescent state automatically
Specifications
| Conductivity | Temperature | Salinity | |
|---|---|---|---|
| Range | 0 to 7 Sm-1 | -5 to 35°C | |
| Initial accuracy | 0.0003 Sm-1 | 0.002°C | 0.005 (typical) |
| Resolution | 0.00001 Sm-1 | 0.0001°C | 0.0002 (typical) |
| Typical stability (per month) | 0.0003 Sm-1 | 0.0002°C | 0.003 (typical) |
Further details can be found in the manufacturer's specification sheet.
RRS James Cook Cruise JC064 Surface Hydrography Data Processing Procedures
Originator's Data Processing
Data were taken from the ship's TECHSAS streams and formatted into MSTAR netCDF format. All times were defined as seconds from 00:00:00 01/01/2011.
The hydrography measurements were performed by a number of instruments in the ship's flow through system and a temperature sensor (SBE38) located near the flow through intake. The depth of the flow through intake was 5.5m. A SBE45 MicroTSG was used in the wetlab, measuring the temperature and conductivity of the water pumped up through the ship's flow through system.
Salinity data were calibrated by calibrating the conductivity channel and then deriving salinity. Discrete bottle conductivities were compared with the TSG conductivities.
Fluorescence data were converted from raw voltages by the Originator using the formulae:
CHL (µg/l) = 13.8 x (Output - 0.056)
| Filename | Content Description | Format | Interval | Start Date (dd/mm/yyyy) | Start Time (UTC) | End Date (dd/mm/yyyy) | End Time (UTC) |
|---|---|---|---|---|---|---|---|
| met_tsg_jc064_01_calib_wnav.nc | Sea surface hydrography | MSTAR | 0.9 - 1.2 seconds | 29/08/2011 | 11:51:16 | 06/10/2011 | 23:59:58 |
BODC Data Processing
All 1 second sea surface hydrographic data for cruise JC064 were supplied to BODC in an MSTAR format and transferred to BODC's internal NetCDF format (QXF). Some unit conversions were required and these were applied before the data were transferred. Data were averaged at 30 second intervals.
During transfer the originator's variables were mapped to unique BODC parameter codes. The following table shows the parameter mapping:
| Original File | Originator's Parameter | Originator's Units | Description | BODC Parameter Code | BODC Units | Comments |
|---|---|---|---|---|---|---|
| met_jc064_true.nc | lat | ° (+ve N) | Latitude | ALATGP01 | ° (+ve N) | - |
| met_jc064_true.nc | long | ° (+ve E) | Longitude | ALONGP01 | ° (+ve E) | - |
| met_tsg_jc064_01_calib_wnav.nc | cond | mS cm-1 | Conductivity | CNDCSG01 | S m-1 | Unit conversion required: * 0.1 |
| met_tsg_jc064_01_calib_wnav.nc | fluo | mgl-1 | Chlorophyll-a concentration | CPHLPM01 | mg m-3 | Calibrated by Originator |
| met_tsg_jc064_01_calib_wnav.nc | salin | psu | Salinity | PSALSG01 | dimensionless | Calibrated against discrete sample data by Originator |
| met_tsg_jc064_01_calib_wnav.nc | temp_m (temp_r) | °C | Sea surface temperature | TEMPHG01 | °C | Calibrated against surface CTD data at BODC |
| met_tsg_jc064_01_calib_wnav.nc | temp_h | °C | Temperature of conductivity measurement | TMESSG01 | °C | - |
| met_tsg_jc064_01_calib_wnav.nc | trans | Millivolt | Raw transmissometer voltage | TVLTDZ01 | Volts | Conversion: *0.001 |
| - | - | - | Attenuance | ATTNUN25 | m-1 | Derived by BODC from transmittance. |
Following transfer, all data were screened using BODC in-house visualisation software. Suspect data values were assigned the appropriate BODC data quality flags. Missing data values, where present, were changed to a BODC data value and assigned a data quality flag.
Temperature
The hull temperature data were calibrated at BODC using CTD temperature data. Note, the CTD measurements have not been verified against an independent source. The offset (CTD temperature - underway temperature) was examined to see if it varied with time or temperature. Outliers, with high standard deviations, were identified and discarded. No significant correlation was established between offset and CTD temperature or time. Therefore the data correction is in the form of a mean offset (n=12, standard deviation = 0.02294):
Calibrated underway temperature = underway temperature - 0.02100
Beam attenuation
Raw transmissometer data were converted to beam attenuation using the formulae:
c=-1/0.25 x ln(tr)
where
Tr=(Vsig-0.059)/(4.679-0.059)
No other calibrations were carried out by BODC.
Project Information
RAPID- Will the Atlantic Thermohaline Circulation Halt? (RAPID-WATCH)
RAPID-WATCH (2007-2014) is a continuation programme of the Natural Environment Research Council's (NERC) Rapid Climate Change (RAPID) programme. It aims to deliver a robust and scientifically credible assessment of the risk to the climate of UK and Europe arising from a rapid change in the Atlantic Meridional Overturning Circulation (MOC). The programme will also assess the need for a long-term observing system that could detect major MOC changes, narrow uncertainty in projections of future change, and possibly be the start of an 'early warning' prediction system.
The effort to design a system to continuously monitor the strength and structure of the North Atlantic MOC is being matched by comparative funding from the US National Science Foundation (NSF) for the existing collaborations started during RAPID for the observational arrays.
Scientific Objectives
- To deliver a decade-long time series (2004-2014) of calibrated and quality-controlled measurements of the Atlantic MOC from the RAPID-WATCH arrays.
- To exploit the data from the RAPID-WATCH arrays and elsewhere to determine and interpret recent changes in the Atlantic MOC, assess the risk of rapid climate change, and investigate the potential for predictions of the MOC and its impacts on climate.
This work will be carried out in collaboration with the Hadley Centre in the UK and through international partnerships.
Mooring Arrays
The RAPID-WATCH arrays are the existing 26°N MOC observing system array (RAPIDMOC) and the WAVE array that monitors the Deep Western Boundary Current. The data from these arrays will work towards meeting the first scientific objective.
The RAPIDMOC array consists of moorings focused in three geographical regions (sub-arrays) along 26.5° N: Eastern Boundary, Mid-Atlantic Ridge and Western Boundary. The Western Boundary sub-array has moorings managed by both the UK and US scientists. The other sub-arrays are solely led by the UK scientists. The lead PI is Dr Stuart Cunningham of the National Oceanography Centre, Southampton, UK.
The WAVE array consists of one line of moorings off Halifax, Nova Scotia. The line will be serviced in partnership with the Bedford Institute of Oceanography (BIO), Halifax, Canada. The lead PI is Dr Chris Hughes of the Proudman Oceanographic Laboratory, Liverpool, UK.
All arrays will be serviced (recovered and redeployed) either on an annual or biennial basis using Research Vessels from the UK, US and Canada.
Modelling Projects
The second scientific objective will be addressed through numerical modelling studies designed to answer four questions:
- How can we exploit data from the RAPID-WATCH arrays to obtain estimates of the MOC and related variables?
- What do the observations from the RAPID-WATCH arrays and other sources tell us about the nature and causes of recent changes in the Atlantic Ocean?
- What are the implications of RAPID-WATCH array data and other recent observations for estimates of the risk due to rapid change in the MOC?
- Could we use RAPID-WATCH and other observations to help predict future changes in the MOC and climate?
Data Activity or Cruise Information
Cruise
| Cruise Name | JC064 |
| Departure Date | 2011-09-10 |
| Arrival Date | 2011-10-09 |
| Principal Scientist(s) | Stuart A Cunningham (National Oceanography Centre, Southampton) |
| Ship | RRS James Cook |
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 |
