Metadata Report for BODC Series Reference Number 1012822

• 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

Data Quality Report (JR106 sea surface hydrography)

During the cruise there were periods when the pump was switched off or the lines to the instruments were blocked with ice. These were easily identified as low values (~0) in the INFLTF01 flow rate channel. During these periods corresponding data in CNDCSG01, PSALSU01, TMESSG01 and SVELSG01 were flagged as suspect with the appropriate BODC quality control flag. The parameters CPHLUMTF and TMESFL01 lag the pump by up to 5 minutes or have slower response times. Values within this period are also suspect.

While the ship was in port, TEMPHU01 values were flagged as suspect because the ship was warming the surrounding water. The ship was in port from the 11^th August 2004 until 16:00 on the 13^th August 2004.

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

Turner Designs 10AU Field Fluorometer

The Turner Designs 10AU is designed for continuous-flow monitoring or discrete sample analyses of fluorescent species. A variety of optical kits with appropriate filters and lamps are available for a wide range of applications. Individual filters and lamps are also available for customised applications.

Standard optical kits include those for chlorophyll-a (extracted and/or in vivo), phycocyanin, phycoerythrin, CDOM, ammonium, rhodamine and fluorescein dye tracing, crude oil, refined oil, histamine and optical brighteners.

The instrument's light source is a 4 watt lamp and the detector is a photomultiplier tube with a standard detection range of 300-650 nm. A red-sensitive version with a detetion range of 185-970 nm is also available.

Specifications

Further details can be found in the manufacturer's specification sheet.

Instrument Description (JR106 sea surface hydrography)

Data were collected using the integrated underway system on the RRS James Clark Ross. Contacts for specific instrumentation queries can be found on the British Antarctic Survey (BAS) website (BAS website).

The data were logged on a PC-based oceanlogger logging system, built in-house at BAS, with the primary purpose of logging measurements from various of the ship's continuously-run data sources. Accordingly, it drew data from the ship's pumped non-toxic supply, plus assorted meteorological parameters. The instruments with an analogue output were connected to self-contained digitising Nudam modules located close to the relevant instrument. The modules were then interrogated by the controlling PC using the RS485 protocol.

The following oceanographic instrumentation were connected to the ships non-toxic sea-water supply:

References

Cruise report - JR106b, RRS James Clark Ross, NERC AutoSub under ice thematic Programme, Kangerdlugssuaq Fjord and Shelf, East Greenland.

BODC JR106b documentation

Litre Meter flow meter

A flow meter used to monitor water flow rates for pumped systems such as ships' continuous seawater supplies.

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

Further details can be found in the manufacturer's specification sheet.

Data processing (JR106 sea surface hydrography)

Originator's Data Processing

Sampling Strategy

The underway oceanlogger system was run continuously throughout the cruise with data logging every 2 seconds.

References

Cruise report - JR106b, RRS James Clark Ross, NERC AutoSub under ice thematic Programme, Kangerdlugssuaq Fjord and Shelf, East Greenland.

BODC JR106b documentation

Processing at BODC

All underway sea surface hydrography, meteorology and ship's navigation data were provided to BODC in UKORS binary format files. Sea surface hydrography data were received in the following UKORS raw binary file.

All underway sea surface hydrography, meteorology and ship's navigation files were merged into a common BODC NetCDF format file following BODC standard procedures and using time (GMT) as the primary linking key. This allowed surface hydrography to be merged with navigational positions from the bestnav system. Navigational and meteorological processing are described elsewhere. Data calibrations were applied as appropriate (see calibrations section). Subsequently, the NetCDF file was split into 3 separate files, one containing all sea surface hydrography data, one containing all meteorology data and one containing all navigation data.

The originator's variables were mapped to unique BODC parameter codes as follows:

* Time is mapped to common AADYAA01 and AAFDZZ01 data channels with a 30 second temporal resolution.

Each data channel was visually inspected on a graphics workstation and any spikes or periods of dubious data were flagged as suspect. The capabilities of the workstation screening software allows all possible comparative screening checks between channels (e.g. to ensure corrected wind data have not been influenced by changes in ship's heading). The system also has the facility of simultaneously displaying the data and the ship's position on a map to enable data screening to take oceanographic climatology into account.

Calibration

Calibrations of the salinity, temperature and chlorophyll values against the underway salinity samples and CTD profiles were undertaken by BODC. For all parameters the offset (reference minus parameter to calibrate) failed the Anderson-Darling test for normality. All offsets appeared homogeneous so linear regression was attempted.

Salinity

There were no discrete underway salinity samples from this leg of the JR106 cruises. The cruise is also in a region of sea-ice and there were only 8 points to calibrate against, these were also biased to the start of the cruise. The subsequent JR106B leg of the cruise immediately followed this leg and also included discrete samples.

A calibration dataset was built using the following data:

• The CTD data from JCR106 (assuming a non-toxic sea-water intake depth of 6 m)
• The CTD data from JCR106B (assuming a non-toxic sea-water intake depth of 6 m), excluding the data from within the Kangerdlugssuaq fjord
• The underway discrete samples from JCR106B, excluding the data from within the Kangerdlugssuaq fjord

This produced a calibration dataset with 36 values spanning 22:48:59 18th August 2004 to 19:28:00 10th September 2004. The salinity offset was calculated as the Reference value (CTD or sample) minus underway value.

Regression of salinity offsets verses time

Regression of salinity offsets verses reference data

In both regressions the R² is too small (less than 95%) and the P value too large (greater than 0.05) for the results to be considered significant.

When plotted a small offset from zero is visible throughout the series. This had a mean of 0.0351 and a standard deviation of 0.0673 (N=36). The high standard deviation suggested the the offset should not be applied.

Sea Surface Temperature (SST)

There were no calibrated temperature data for this cruise, only the uncalibrated temperatures from the CTD so an inter-comparison was undertaken. This cruise is in a region of sea-ice so there were only 10 points to calibrate against, these were also biased to the start of the cruise. The subsequent JR106B leg of the cruise immediately followed this leg so a calibration dataset was built using the following data:

• The CTD data from JCR106 (assuming a non-toxic sea-water intake depth of 6 m)
• The CTD data from JCR106B (assuming a non-toxic sea-water intake depth of 6 m), excluding the data from within the Kangerdlugssuaq fjord

This produced a calibration dataset with 23 values spanning 22:48:59 18th August 2004 to 17:24:59 10th September 2004. The temperature offset was calculated as the Reference value (CTD or sample) minus underway value.

Regression of salinity offsets verses time

Regression of salinity offsets verses reference data

In both regressions the R² is too small (less than 95%) and the P value too large (greater than 0.05) for the results to be considered significant.

When plotted a small offset from zero is visible throughout the series. This had a mean of -0.1166 and a standard deviation of 0.1216 (N=23). The high standard deviation suggested the offset should not be applied.

Chlorophyll

There were no calibrated chlorophyll data for this cruise, only the uncalibrated chlorophyll from the CTD so an inter-comparison was undertaken. This cruise is in a region of sea-ice so there were only 8 points to calibrate against, these were also biased to the start of the cruise. The subsequent JR106B leg of the cruise immediately followed this leg so a calibration dataset was built using the following data:

• The CTD data from JCR106 (assuming a non-toxic sea-water intake depth of 6 m)
• The CTD data from JCR106B (assuming a non-toxic sea-water intake depth of 6 m)

This produced a calibration dataset with 50 values spanning 22:48:59 18th August 2004 to 17:24:59 10th September 2004. The chlorophyll offset was calculated as the Reference value (CTD or sample) minus underway value.

Regression of salinity offsets verses time

Regression of salinity offsets verses reference data

In both regressions the R² is too small (less than 95%) but the P value is small (less than 0.05) indicating significance. This is strongest in the regression against reference data and clearly apparent when the data were plotted. The series of offsets had a mean of -0.0187 and a standard deviation of 0.1052 (N=50). Because both the reference and the underway data were uncalibrated no calibration was applied and the result is described here for information.

Project Information

AutoSub Under Ice (AUI) Programme

AutoSub was an interdisciplinary Natural Environment Research Council (NERC) thematic programme conceived to investigate the marine environment of floating ice shelves with a view to advancing the understanding of their role in the climate system.

The AUI programme had the following aims:

• To attain the programme's scientific objectives through an integrated programme based on interdisciplinary collaborations and an international perspective
• To develop a data management system for the archiving and collation of data collected by the programme, and to facilitate the eventual exploitation of this record by the community
• To provide high-quality training to develop national expertise in the use of autonomous vehicles in the collection of data from remote environments and the integration of such tools in wider programmes of research
• To stimulate and facilitate the parameterising of sub-ice shelf processes in climate models, and to further demonstrate the value of autonomous vehicles as platforms for data collection among the wider oceanographic and polar community

Following the invitation of outline bids and peer review of fully developed proposals, eight research threads were funded as part of AUI:

Physical Oceanography

• ISOTOPE: Ice Shelf Oceanography: Transports, Oxygen-18 and Physical Exchanges.
• Evolution and impact of Circumpolar Deep Water on the Antarctic continental shelf.
• Oceanographic conditions and processes beneath Ronne Ice Shelf (OPRIS).

Glaciology and Sea Ice

• Autosub investigation of ice sheet boundary conditions beneath Pine Island Glacier.
• Observations and modelling of coastal polynya and sea ice processes in the Arctic and Antarctic.
• Sea ice thickness distribution in the Bellingshausen Sea.

Geology and Geophysics

• Marine geological processes and sediments beneath floating ice shelves in Greenland and Antarctica: investigations using the Autosub AUV.

Biology

• Controls on marine benthic biodiversity and standing stock in ice-covered environments.

The National Oceanography Centre Southampton (NOCS) hosted the AUI programme with ten further institutions collaborating in the project. The project ran from April 2000 until the end of March 2005, with some extensions to projects beyond this date because of research cruise delays. The following cruises were the fieldwork component of the AUI project:

Table 1: Details of the RRS James Clark Ross AUI cruises.

All the cruises utilised the AutoSub autonomous, unmanned and untethered underwater vehicle to collect observations beneath sea-ice and floating ice shelves. AutoSub can be fitted with a range of oceanographic sensors such as:

• Conductivity Temperature Depth (CTD) instruments
• Acoustic Doppler Current Profillers (ADCP)
• A water sampler
• Swath bathymetry systems
• Cameras

In addition to use of AutoSub during each cruise measurements were taken from ship. These varied by cruise but included:

• Ship underway measurements and sampling for parameters such as:
  • Salinity
  • Temperature
  • Fluorescence
  • Oxygen 18 isotope enrichment in water
  • Bathymetry using a swath bathymetry system
• Full-depth CTD casts for with observations of samples taken for parameters such as:
  • Salinity
  • Temperature
  • Fluorescence
  • Optical transmissivity
  • Dissolved oxygen
  • Oxygen 18 isotope enrichment in water
  • Water CFC content
• Sea floor photography and video using the WASP system
• Sea floor sampling with trawls/rock dredges
• Sea ice observations (ASPeCt), drifters and sampling

The AutoSub project also included numerical modelling work undertaken at University College London, UK.

The project included several firsts including the first along-track observations beneath an ice shelf using an autonomous underwater vehicle. The AutoSub vehicle was developed and enhanced throughout this programme and has now become part of the NERC equipment pool for general use by the scientific community. Further information for each cruise can be found in the respective cruise reports (links in Table 1).

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: