Metadata Report for BODC Series Reference Number 1902118

• 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

JR20120120 (JR255A) Underway: Meteorology Data Quality Document

Due to suspected issues with calculations, the parameters true wind direction, true wind speed, true wind u and true wind v have not been included in the final file but are available upon request.

Suspect M flags were added to the data where the primary sensors displayed periods of constant zeros and a clear difference from the secondary sensors. This may be due to data dropout.

Cycle 18323 of the data series was deleted due to a duplicate time. All corresponding data for this cycle was also deleted as the values were consistent with the previous instance of this time stamp.

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

Gill Windobserver 70 (ultrasonic) anemometer

A solid state, heated ultrasonic anemometer. Designed for use within the aviation industry and for more extreme weather conditions. It measures the times taken for an ultrasonic pulse of sound to travel from the North transducer to the South transducer, and compares it with the time for a pulse to travel from S to N transducer. Likewise times are compared between West and East, and E and W transducer. The wind speed and direction (and the speed of sound) can then be calculated from the differences in the times of flight on each axis. This calculation is independent of factors such as temperature. It uses 150 Watts of electrical heating in the anemometer head to prevent icing. Wind speed accuracy is +/-2% at 12 m/s. Wind direction accuracy is +/-2 degrees at 12 m/s.

For more information, please see this document: https://www.bodc.ac.uk/data/documents/nodb/pdf/Gill_WindObserver70_2017.pdf

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 Hygromet MP102H and MP402H temperature and humidity probes

This meteorological probe measures humidity and temperature with the plug-in HygroClip HC2-S3 sensor module, and can also be equipped with a signal conditioned Pt100 temperature probe.

The two models differ in that the MP102H produces a voltage output while the MP402H produces a current output. Other characteristics are common to both models.

The specification sheet can be accessed here Rotronic MP102H and MP402H.

Specifications

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.

JR20120120 (JR255A) Underway: Meteorology Instrument Description

The navigation instruments used to collect this data set are presented in the table below. The sensors were located on the ship's meteorological mast. There were two sensors for each parameter, both of which are present in the final file.

JR20120120 (JR255A) Underway: Meteorology Processing Procedures Document

Originator's Data Processing

Sampling Strategy

RRS James Clark Ross cruise JR255A was deployed as part of the Gliders: Excellent New Tools for Observing the Ocean (GENTOO) project. JR255A was a 2 week cruise departing from port Stanley in the Falkland Islands. The GENTOO fieldwork took place in the Weddell Sea where gliders were used primarily for data gathering.

A script on the JRLC server (written by Bastien Queste) was run automatically every hour at quarter past to update the file the oceanlogger matlab file. The routine first creates a query file which contains a GMT start and end time. The start time is either the first date recorded by the oceanlogger (18:36 17/01/2012) or the last date stored in the oceanlogger matlab file (if present) and the current time as an end time.

All instruments, except the anemometer, which was on a mast 22.5 m above sea level, were located on the ship's meteorological mast, the sensors were placed side by side, 20 m above sea level.

The data streams were logged every second to the SCS system and merged into a comma separated file format, whereas the header information was stored in .TPL files. This file also contained data from sea surface hydrography sensors.

Meteorological data originated from duplicate sensors located on the RRS James Clark Ross meteorological mast.

Before the results were mapped, the outliers are removed from the data. The Originator chooses a threshold T (e.g. 20), for each parameter and then calculates x1 —value of the parameter corresponding to the Tth percentile- and x2 —for the 100-T th percentile.

After testing the scaling factor (SF) is set to 7, then the Originator sets to NaN any outliers with the following equations:

x < x1 — SF*(x2 — x1)

x > x2 + SF*(x2 — x1)

Files delivered to BODC

BODC Processing

The files mentioned above were selected for data banking as they contain the best version of processed meteorological parameters. Data were banked at BODC following standard data banking procedures, including reduction through averaging, checking meteorological channels for improbable values, working out absolute wind speed and direction, and screening the data for anomalous values. The originator's variables were mapped to appropriate BODC parameter codes as follows:

JR255_oceanlogger.mat

BODC's procedures included the transfer of originator's parameters into BODC codes and visual screening in Edserplo. N flags were applied during the transfer to absent values.

The meteorological data were collected with two sets of instruments. Data from both sensors, primary and secondary, were transferred and visually checked.

Project Information

Gliders: Excellent New Tools for Observing the Ocean (GENTOO)

Funding

Funding was provided by NERC through the 11^th round of the Antarctic Funding Initiative (AFI), an annual competition-based award which is supported logistically by the British Antarctic Survey (BAS). The award had a total value of £1,070,531 which was split between different researchers at various international institutions in the form of grants, fellowships and training grant records.

Project dates - 06 September 2010 to 31 March 2015

Background

Research has shown that surface waters surrounding Antarctica play an important role in driving the global oceanic circulation as they are subjected to ideal physical conditions to become denser and sink at specific locations. The mapping of these locations and the identification of the properties of these water cells have been relying on expensive and season-dependent shipborne observations in impractical polar seas. This study aims at revealing the potential of Seagliders, which are autonomous, inexpensive and sustainable underwater vehicles able to carry out certain physical, biological and chemical measurements of the water column all year round. Seagliders were deployed in the Weddell Sea, as the recent collapse of the Larsen Ice Shelf has raised questions on whether dense water may now be spilling off the continental shelf on the eastern side of the Antarctic Peninsula. Changes in location of deep water formation may affect local oceanic currents and consequently the global circulation and the Earth's climate; reliable mapping and description of the Antarctic waters are therefore key to generate accurate climate and circulation models and predictions. Possible changes in the ocean currents also affect the organisms living in the waters near Antarctica. In particular, krill lay eggs around the Antarctic Peninsula and rely on ocean currents to transport them to South Georgia. It is important to determine whether changes in the local circulation may impact krill's ecosystem, as animals such as whales, seals and penguins feed on them and they support a multi-million pound krill fishing industry. In light of the decreasing availability of resources for an increasing human population, the possibility of krill's immunity to temperature and circulation changes may result in a popular food resource for people in the future.

Objectives

The main objectives of the GENTOO project depend on a critical evaluation of the ability to measure current velocity and krill biomass from a glider.

1) To quantify and understand the possible new source of dense water overflow and its variability; to determine the outflow's potential as an early indicator of Antarctic climate change; to assess the impact of changing dense overflows on the locations and strengths of the surface currents and frontal jets; to provide valuable constraints for climate models that describe how changes in ocean circulation feedback on and regulate climate change in polar latitudes.

2) To determine the krill biomass distribution and (temporal and spatial) variability to the east of the Antarctic Peninsula and its likely impact on the circumpolar krill ecosystem; to assess the impact of any variations in the location of the frontal jets (from objective 1) on the krill biomass distribution; to alleviate a severe regional lack of field data on krill, a key species in the Antarctic food web.

Participants

• University of East Anglia, United Kingdom (Lead Research Organisation)
• NOAA - National Oceanic and Atmospheric Administration, United States
• Bjerknes Centre for Climate Research, Norway
• AWI - Alfred Wegener Institute for Polar and Marine Research, Germany
• VIMS - Virginia Institute of Marine Science, United States

• Prof. Karen Heywood, University of East Anglia, Environmental Science (Principal Investigator)
• Dr. Sophie Fielding, NERC British Antarctic Survey, Science Programmes
• Prof. Gwyn Griffiths, National Oceanography Centre, Science and Technology
• Dr. Stuart Dalziel, University of Cambridge, Applied Mathematics and Theoretical Physics
• Dr. Eugene Murphy, NERC British Antarctic Survey, Science Programmes
• Dr. Andrew Thompson, California Institute of Technology, Environmental Science and Engineering.

Methodology

During cruise RRS James Clark Ross 255A three Seagliders were deployed, and a hydrographic survey was undertaken together with nets and underway biological, chemical and physical measurements. The data gathered was analysed to meet the objectives listed above. Please read the 'Instrumentation' section below, and visit the GENTOO website for more information on the methodology and outcomes of the various research studies.

Fieldwork

• RRS James Clark Ross 255A - 20 January 2012 to 03 February 2012. Port of arrival and departure is Stanley, Falkland Islands (Malvinas). Study area - Drake Passage, Weddell Sea, Powell Basin. Principal Scientist - Dr. Karen Heywood, University of East Anglia. This was the glider deployment cruise and the primary data gathering exercise.
• RRS James Clark Ross 255B - 07 February 2012 to 22 March 2012. Port of arrival and departure is Stanley, Falkland Islands (Malvinas). This was the glider recovery cruise; other projects not linked to GENTOO shared the voyage.

Instrumentation

• Seagliders - three in total, each equipped with a Seabird CT sail (i.e. free-flushed temperature and conductivity sensors), Aandera oxygen optode and a WETLabs ECO Triplet. (Biddle et al. 2015)
• SeaBird (SBE) CTD-11plus rosette equipped with 24 12-litre Niskin bottles. Sensors installed are SBE 43 Oxygen sensor, LI-COR Biospherical PAR Sensor, Chelsea Aqua 3 Fluorometer, WET Labs C-Star Transmissometer, and Altimeter sensor.
• 300 kHz WorkHorse (WH) Lowered Acoustic Doppler Current Profiler (LADCP)
• 75 kHz RD Instruments Ocean SUrveyor (OS75) Vessel-Mounted Acoustic Doppler Current Profiler (ADCP)
• Surface drifters: 20 Clearsat-15 Minidrogue drifters with a GPS navigation option and 20 Clearsat-15 SVP Minidrigue drifters with Argos data telemetry, both purchased from Clearwater Instrumentation, Inc.
• Three AOEX-SBE Argo floats profilers produced by Webb Research Corporation USA.
• RMT8 Nets Macrozooplankton
• Guildline Autosal salinometer
• Winkler O₂ titrator
• Simrad EK60 Echo Sounder
• Underway - navigation, surface and meteorology.

Contacts

References

Biddle, L.C., Kaiser J., Heywood K.J., Thompson A.F., and Jenkins A., 2015. Ocean glider observations of iceberg-enhanced biological production in the northwestern Weddell Sea, Geophys. Res. Lett. (42), 459-465.

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: