Metadata Report for BODC Series Reference Number 1012809

• 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

Meteorology data quality Document

In low light the PAR and TIR light instruments (parameters IRRDSS01, IRRDSS02, CSLRZZ01 and CSLRZZ02) recorded small negative values. A possible cause is that a recent dark offset had not been applied to the measurements by the originator. These values are also suspect and are marked accordingly.

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

Kipp and Zonen PAR Lite Photosynthetically Active Radiation sensor

An atmospheric radiometer that measures photosynthetically active radiation (PAR) by means of a Teflon diffuser, an optical interference filter and a photo-diode detector. The sensor measures the PAR received over the entire hemisphere and the diffuser's sensitivity is proportional to the cosine of the angle of incidence of the incoming radiation. The optical filter has a spectral response of 400-700 nm (PAR wavelengths) and the photodiode creates a voltage output that is proportional to the incoming radiation.

Specifications

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

Kipp and Zonen SP Lite and SP Lite2 Silicon Pyranometer

An atmospheric pyranometer that measures solar radiation over the range 400-1100 nm by means of a silicon photo-diode detector mounted in a diffuser. The sensor measures the radiation received over the entire hemisphere and the diffuser's sensitivity is proportional to the cosine of the angle of incidence of the incoming radiation. The photodiode creates a voltage output that is proportional to the incoming radiation. The SP Lite2 supersedes the SP Lite and features an improved sensitivity and faster response time than its predecessor.

Specifications

Further details can be found in the manufacturer's specification sheets for the SP Lite and SP Lite2.

Rotronic Precision meteorology probes for relative humidity and temperature: MP100A and MP400A series

The MP100A and MP400A series probes comprise a platinum (Pt100) resistance thermometer (with direct or linear output signal) and a Rotronic HYGROMER-C94 humidity sensor.

Instruments from the two series function in the same manner, although the the MP100A series produces voltage output while the MP400A series produces a current output (amps). Differences between the various models in each series are restricted to operational temperature ranges, supply voltages and humidity output signals.

The following specifications are common to all MP100A and MP400A series probes:

Differences between the models are detailed below:

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

Vaisala PTB210 Digital Barometer

The basic specifications for this pressure sensor are as follows:

• Manufacturer: Vaisala
• Type: Silicon capacitive sensor
• Model: PTB210
• Range: 900 - 1100 hPa
• Output: 0-5VDC
• Total Accuracy (20°C): ±0.30hPa
• Operating temperature: -40 to +60 deg C
• Weight: 110g
• Certification Ingress Protection: IP65

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

Instrument Description (JR106 meteorology)

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 meteorological instrumentation was used:

Where two sensors were used, they are physically mounted in close proximity to each other. Two were used for redundancy purposes.

References

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

BODC JR106b documentation

Meteorology processing document

Originator's processing

The data from the oceanographic and meteorological instrumentation were read into Unix daily files to produce an ocean.*** file for the particular Julian day (where *** is the Julian day), at intervals from 2 seconds upwards. The data were mapped and converted to the same time interval as the navigational data, using the bestnav_all_jr106.mat file. Corresponding latitudes and longitudes from the bathymetry data were also included in the output file. The daily mapped data were saved in the oceanlog_30sec_all_jr106s.mat containing data for the entire cruise.

BODC Processing

Data were received as three binary .mat Matlab files named bestnav_all_jr106.mat, merged_all_jr106s and oceanlog_30sec_all_jr106s.mat. Each file held data from the navigation, bathymetry and oceanographic/meteorological respectively although each file contained both position and time data. The data covered the time period of 18:24:29 on the 29th August 2004 to 23:59:29 on the 10th September 2004, and so include data from the previous cruise (JCR106). Data from the previous cruise were trimmed from this series as they are included in the JCR016 data submission.

All underway sea surface hydrography, meteorology and ship's navigation files are merged into a single NetCDF file using time (GMT) as the primary linking key.

Following this, the NetCDF file was then split into three separate NetCDF files, with the data grouped by instrument position, by BODC generated Matlab code. One file contained data for sea surface hydrography, one for meteorology and the final NetCDF file held navigation data.

During transfer the original variables were mapped to unique BODC derived parameter codes. Not all parameters present in the original NetCDF file were transferred into the meteorlogical NetCDF file. Some parameters were processed further and thus superseded. This is the case with the PAR and TIR channels where each pair of sensors was merged to create one combined channel. When TIR and PAR channels were merged the greatest value at each time was taken.

The parameter mapping is described in the table below.

Each data channel was visually inspected on a graphics workstation and any spikes or periods of dubious data are 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.

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: