Metadata Report for BODC Series Reference Number 1810836
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
RRS JR15003 CTD Data Quality Report
The transmittance data (POPTDR01) have been flagged by BODC for all casts as the data values are all over 100 %.
The attenuation data (BB142RVL) are constant throughout the deployment for both casts 7 and 8, 6th January 2016 at 18:06:50 and at 20:11:01 respectively.
These data should be used with caution.
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
Sea-Bird Dissolved Oxygen Sensor SBE 43 and SBE 43F
The SBE 43 is a dissolved oxygen sensor designed for marine applications. It incorporates a high-performance Clark polarographic membrane with a pump that continuously plumbs water through it, preventing algal growth and the development of anoxic conditions when the sensor is taking measurements.
Two configurations are available: SBE 43 produces a voltage output and can be incorporated with any Sea-Bird CTD that accepts input from a 0-5 volt auxiliary sensor, while the SBE 43F produces a frequency output and can be integrated with an SBE 52-MP (Moored Profiler CTD) or used for OEM applications. The specifications below are common to both.
Specifications
Housing | Plastic or titanium |
Membrane | 0.5 mil- fast response, typical for profile applications 1 mil- slower response, typical for moored applications |
Depth rating | 600 m (plastic) or 7000 m (titanium) 10500 m titanium housing available on request |
Measurement range | 120% of surface saturation |
Initial accuracy | 2% of saturation |
Typical stability | 0.5% per 1000 h |
Further details can be found in the manufacturer's specification sheet.
JR15003 CTD Rosette Instrument Description
CTD Unit and Auxiliary Sensors
A Sea-Bird 11plus CTD system was used on cruise JR15003. This was mounted on a 24-way stainless steel rosette frame, equipped with 24 Niskin bottles. The CTD was fitted with the following scientific sensors:
Sensor | Serial Number | Last calibration date | Comments |
---|---|---|---|
Sea-Bird SBE 911plus CTD | 0458 | - | - |
Paroscientific Digiquartz depth sensor | 0707 | 22nd June 2015 | - |
Sea-Bird SBE 3plus (SBE 3P) temperature sensor | 5766 | 18th March 2015 | - |
Sea-Bird SBE 3plus (SBE 3P) temperature sensor | 2705 | 10th June 2015 | - |
Sea-Bird SBE 35 thermometer | 0024 | - | - |
Sea-Bird SBE 4C conductivity sensor | 2248 | 14th July 2015 | - |
Sea-Bird SBE 4C conductivity sensor | 4471 | 12thMarch 2015 | - |
Tritech PA-200 Altimeter | 163162 | 28th May 2015 | - |
Sea-Bird SBE 43 dissolved oxygen sensor | 676 | 02nd June 2015 | - |
WET Labs {Sea-Bird WETLabs} C-Star transmissometer | 1399 | 30th June 2015 | Red light transmissometer. |
Chelsea Technologies Group Aquatracka III fluorometer | 088-249 | 11th May 2015 | - |
WET Labs ECO FLBB-RTD Fluorometer | 3697 | 23rd September 2014 | Only used from Cast 4 onwards |
Biospherical QCD-905L underwater PAR sensor | 7274 | 24th April 2013 | - |
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.
SeaBird SBE35 Deep Ocean Standards Thermometer
The SBE 35 is a high precision thermometer that can be used in fixed point cells or at depths up to 6800 m. It is not affected by shock and vibration, allowing it to be used in calibration laboratories and for thermodynamic measurement of hydro turbine efficiency.
The SBE35 can be used with the SBE32 Carousel Water Sampler and with a real-time or autonomous CTD system. In this case, an SBE35 temperature measurement is collected each time a bottle is fired and the value is stored in EEPROM (Electrically Erasable Programmable Read-Only Memory), eliminating the need for reversing thermometers while providing a high accuracy temperature reading.
The SBE35 is standardized in water triple point (0.0100 °C) and gallium melting point (29.7646 °C) cells, following the methodology applied to the Standard-Grade Platinum Resistance Thermometer (SPRT). However, it does not need a resistance bridge, making it more cost-efficient than an SPRT.
Temperature is determined by applying an AC excitation to reference resistances and an ultrastable aged thermistor. Each of the resulting outputs is digitized by a 20-bit A/D converter. The AC excitation and ratiometric comparison uses a common processing channel, which removes measurement errors due to parasitic thermocouples, offset voltages, leakage currents and gain errors.
Specifications
Measurement range | -5 to 35°C |
Accuracy | 0.001°C |
Typical stability | 0.001°C year-1 |
Resolution | 0.000025°C |
Data storage | up to 179 samples |
Baud rate | 300 |
Further details can be found in the manufacturer's specification sheet and manual.
Chelsea Technologies Group Aquatracka MKIII fluorometer
The Chelsea Technologies Group Aquatracka MKIII is a logarithmic response fluorometer. Filters are available to enable the instrument to measure chlorophyll, rhodamine, fluorescein and turbidity.
It uses a pulsed (5.5 Hz) xenon light source discharging along two signal paths to eliminate variations in the flashlamp intensity. The reference path measures the intensity of the light source whilst the signal path measures the intensity of the light emitted from the specimen under test. The reference signal and the emitted light signals are then applied to a ratiometric circuit. In this circuit, the ratio of returned signal to reference signal is computed and scaled logarithmically to achieve a wide dynamic range. The logarithmic conversion accuracy is maintained at better than one percent of the reading over the full output range of the instrument.
Two variants of the instrument are available, both manufactured in titanium, capable of operating in depths from shallow water down to 2000 m and 6000 m respectively. The optical characteristics of the instrument in its different detection modes are visible below:
Excitation | Chlorophyll a | Rhodamine | Fluorescein | Turbidity |
---|---|---|---|---|
Wavelength (nm) | 430 | 500 | 485 | 440* |
Bandwidth (nm) | 105 | 70 | 22 | 80* |
Emission | Chlorophyll a | Rhodamine | Fluorescein | Turbidity |
Wavelength (nm) | 685 | 590 | 530 | 440* |
Bandwidth (nm) | 30 | 45 | 30 | 80* |
* The wavelengths for the turbidity filters are customer selectable but must be in the range 400 to 700 nm. The same wavelength is used in the excitation path and the emission path.
The instrument measures chlorophyll a, rhodamine and fluorescein with a concentration range of 0.01 µg l-1 to 100 µg l-1. The concentration range for turbidity is 0.01 to 100 FTU (other wavelengths are available on request).
The instrument accuracy is ± 0.02 µg l-1 (or ± 3% of the reading, whichever is greater) for chlorophyll a, rhodamine and fluorescein. The accuracy for turbidity, over a 0 - 10 FTU range, is ± 0.02 FTU (or ± 3% of the reading, whichever is greater).
Further details are available from the Aquatracka MKIII specification sheet.
Biospherical Instruments Log Quantum Cosine Irradiance Sensor QCD-905L
The QCD-905L is a submersible radiometer designed to measure irradiance over Photosynthetically Active Radiation (PAR) wavelengths (400-700 nm). It features a cosine directional response when fully immersed in water.
The sensor is a blue-enhanced high stability silicon photovoltaic detector with dielectric and absorbing glass filter assembly, and produces a logarithmic output. Normal output range is -1 to 6 volts with 1 volt per decade. Typically, the instrument outputs 5 volts for full sunlight and has a minimum output of 0.001% full sunlight, where typical noon solar irradiance is 1.5 to 2 x 1017 quanta cm-2 s-1. The instrument can be calibrated with constants for µE cm-2 s-1 or quanta cm-2 s-1.
The QCD-905L can be coupled to a fixed range data acquisition system like a CTD (Conductivity-Temperature-Depth) profiler or current meter. It has an aluminium and PET housing, and a depth rating of 7000 m.
Specifications
Wavelength | 400 to 700 nm |
Output range | -1 to 6 V, with 1 V decade-1 |
Operating temperature | -2 to 35°C |
Depth range | 0 - 7000 m |
Further details can be found in the manufacturer's manual.
Tritech Digital Precision Altimeter PA200
This altimeter is a sonar ranging device that gives the height above the sea bed when mounted vertically. When mounted in any other attitude the sensor provides a subsea distance. It can be configured to operate on its own or under control from an external unit and can be supplied with simultaneous analogue and digital outputs, allowing them to interface to PC devices, data loggers, telemetry systems and multiplexers.
These instruments can be supplied with different housings, stainless steel, plastic and aluminum, which will limit the depth rating. There are three models available: the PA200-20S, PA200-10L and the PA500-6S, whose transducer options differ slightly.
Specifications
Transducer options | PA200-20S | P200-10L | PA500-6S |
Frequency (kHz) | 200 | 200 | 500 |
Beamwidth (°) | 20 Conical | 10 included conical beam | 6 Conical |
Operating range | 1 to 100 m 0.7 to 50 m | - | 0.3 to 50 m 0.1 to 10 m |
Common specifications are presented below
Digital resolution | 1 mm |
Analogue resolution | 0.25% of range |
Depth rating | 700 , 2000, 4000 and 6800 m |
Operating temperature | -10 to 40°C |
Further details can be found in the manufacturer's specification sheet.
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.
BODC Processing
The CTD data were supplied to BODC as 31 MStar files and converted to the BODC internal format.
During transfer the originator's variables were mapped to unique BODC parameter codes. The following table shows the parameter mapping.
Originator's variable | Units | BODC Code | Units | Comments |
---|---|---|---|---|
press | decibars | PRESPR01 | decibars | - |
pressure_temp | degC | - | - | Not transferred - not an environmental variable |
altimeter | m | AHSFZZ01 | m | - |
temp | degC | TEMPST01 | degC | - |
temp1 | degC | - | - | Secondary channel, not retained |
temp2 | degC | - | - | Secondary channel, not retained |
cond | mS/cm | CNCLCCI1 | S/m | Converted (/10) |
cond1 | mS/cm | - | - | Secondary channel, not retained |
cond2 | mS/cm | - | - | Secondary channel, not retained |
oxygen | µmol/kg | DOXYSC01 | µmol/l | Conversion by BODC to µmol/l using TOKGPR01 |
fluor | µg/l | CPHLPM01 | mg/m3 | µg/l=mg/m3 |
fluore | mg/m3 | CPHLPM02 | mg/m3 | - |
transmittance | % | POPTZZ01 | % | - |
turbidity | m-1/sr | BB117R02 | m/nm/sr | m-1/sr equivalent to m/nm/sr **BB117R02 channel missing from casts 1-3** |
psal | pss-78 | PSALST01 | pss-78 | Calculated from calibrated conductivity measurements, by the originator |
psal1 | pss-78 | - | - | Secondary channel, not retained |
psal2 | pss-78 | - | - | Secondary channel, not retained |
depth | m | DEPHPRST | m | - |
potemp | degC | - | - | Not transferred - can be calculated from pressure, salinity and temperature |
potemp1 | degC | - | - | Not transferred - can be calculated from pressure, salinity and temperature |
potemp2 | degC | - | - | Not transferred - can be calculated from pressure, salinity and temperature |
- | - | OXYSZZ01 | % | Derived by BODC using DOXYSC01, TEMPST01 and PSALST01 |
- | - | POTMCV01 | °C | Derived by BODC using TEMPST01, PSALST01 and PRESPR01. |
- | - | SIGTPR01 | kg m-3 | Derived by BODC using POTMCV01, PSALST01 and PRESPR01 |
- | - | TOKGPR01 | l kg-1 | Derived by BODC using SIGTPR01 |
Following transfer the data were screened using BODC in-house visualisation software. Suspect data values were assigned the appropriate BODC data quality flag. Missing data values, where present, were changed to the missing data value and assigned a BODC data quality flag.
Cruise JR15003 Originator's CTD Data Processing
Sampling Strategy
A total of 31 CTD casts were performed during cruise JR15003 to produce full depth vertical profiles of temperature and salinity at all stations. Water samples from some stations were taken from Niskin bottles and sent to Scripps Institution of Oceanography to analyse dissolved oxygen concentration, nutrients (nitrates, phosphates, silicates), pH/alkalinity, and HPLC/POC (high performance liquid chromatography/particulate organic carbon). CTD casts were conducted at three sites on the western Antarctic Peninsula continental shelf, and the remaining 28 profiles at varying sites while traveling northbound in the Drake Passage. In addition, Lowered Acoustic Doppler Current Profilers (LADCPs) were attached to the CTD frame at the 28 sites along the Drake Passage.
Data Processing
Raw CTD data were transferred from the Sea-Bird deck unit via Sea-Bird software. The binary files were converted using Sea-Bird processing software (SBE Data Processing , Version 7.22.2) to a collection of ASCII (.cnv) files. Then MEXEC programs were run to process the data which included reducing the frequency of the data from 24Hz to 1Hz, calibrating the data, calculating derived variables (psal and potemp), and extracting information from the bottom of the cast identified by the maximum pressure. A calibration was produced for the CTD primary conductivity sensor by merging the salinity sample data with the CTD data. The temperature, salinity, and dissolved oxygen sensors were calibrated post-cruise against independent discrete samples taken from water bottles on the CTD. Details of the MEXEC programs used and further details of the processing performed can be found in the cruise report.
Field Calibrations
Salinity from 344 Niskin bottle samples were analysed and compared to CTD conductivities, and 20 of these comparisons were flagged as questionable. Dissolved oxygen bottle and sensor values were also compared, and of the 166 bottles analysed, two comparisons were flagged as questionable.
Project Information
NE/K010034/1 Isotopic characterisation of nutrient dynamics and Upper Circumpolar Deep Water behaviour in the West Antarctic Peninsula sea ice environment
Introduction
Solo NERC funded grant, 'isotopic characterisation of nutrient dynamics and Upper Circumpolar Deep Water (UCDW) behaviour in the West Antarctic Peninsula sea ice environment' with grant reference NE/K010034/1. The project is led by Dr Sian Henley (University of Edinburgh, School of Geosciences).
Background and Objectives
The research project aims to examine ways in which ongoing climate change and sea ice decline at the West Antarctic Peninsula (WAP) are influencing nutrient budgets and biogeochemical cycling throughout the region. The WAP is an ecologically important region of high primary productivity, where nutrient cycling is known to be crucial to phytoplankton production and its relationship with carbon dioxide dynamics. The study comprises of three components:
- A time-series study over three austral summer growing seasons in Ryder Bay, WAP, to examine temporal changes in fixed nitrogen budgets and cycling, in relation to inter-annual variability in sea ice, water column structure and productivity.
- A ship-based transect from the shelf break to Marguerite Bay to examine deep-water behaviour and its impact on the supply of nutrients to high productivity coastal regions.
- Ship-based sampling across the wider WAP shelf region to examine spatial variability in nutrient dynamics, productivity, sea ice and physical oceanography, and give a broader context to the time-series study.
Fieldwork
Ship based sampling was completed on-board RRS James Clark Ross cruise JR20141231 (JR307, JR308) comprising of full depth CTDs, water sampling for analysis on-board for macro nutrient concentration and RNA sequencing of organic matter. Times Series, study data were collected as part of the Rothera Time Series (RaTS), a long-term monitoring project conducted by the British Antarctic Survey since 1997.
Data Availability
The NERC funded data collected under NE/K010034/1 is restricted to the Principal Investigator for 2 years from the point of data collection. Data is freely available to the public beyond this date.
Data Activity or Cruise Information
Cruise
Cruise Name | JR15003 |
Departure Date | 2015-12-17 |
Arrival Date | 2016-01-13 |
Principal Scientist(s) | Yvonne L Firing (National Oceanography Centre, Southampton) |
Ship | RRS James Clark Ross |
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 |