Metadata Report for BODC Series Reference Number 2242910

• 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 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

Kongsberg EM122 12kHz Multibeam Echosounder

The EM122 is designed to perform seabed mapping to full ocean depth with a high resolution, coverage and accuracy. Beam focusing is applied both during reception and transmission. The system has up to 288 beams/432 soundings per swath with pointing angles, which are automatically adjusted according to achievable coverage or operator defined limits.

This model uses both Continuous Wave and Frequency Modulated sweep pulses with pulse compression on reception, in order to increase the maximum useful swath width. The transmit fan is split in several individual sectors, with independent active steering, in order to compensate for the vessel movements.

In multiplying mode, two swaths per ping cycle are generated, with up to 864 soundings. The beam spacing is equidistant or equiangular and the transmit fan is duplicated and transmitted with a small difference in along track tilt, which takes into account depth coverage and vessel speed, to give a constant sounding separation along track. In high density mode, more than one sounding per beam can be produced, such that horizontal resolution is increased and is almost constant over the whole swath.

The EM122 transducers are modular linear arrays in a Mills cross configuration with separate units for transmit and receive. If used to deliver sub-bottom profiling capabilities with a very narrow beamwidth, this system is known as SBP120 Sub-Bottom Profiler.

The specification sheet can be accessed here Kongsberg EM122.

Specifications

EM122 versions

Processed EM122 multibeam bathymetry survey at Whittard Canyon during cruise DY166: Originator Processing

Sampling Strategy

Multibeam swath bathymetry data were collected with a hull-mounted Kongsberg EM122 echosounder (12 kHz) during RRS Discovery trials cruise DY166 (Principal Scientist Matthew Kingsland) between 18th June - 5th July 2023. The cruise was conducted to complete MARS Autosub 6000 and Autosub Long Range (ALR) trials at Haig Fras and Whittard Canyon.

Data Processing

The data were processed using Quality Positioning Services (QPS) Qimera software and hand edited to remove spurious points. Data were not corrected for tide but some Sound Velocity Profile (SVP) corrections were applied throughout data collection. The data were exported as longitude-latitude-depth triples. SVP data used for corrections were of limited quality and availability. Funding was provided by the National Oceanography Centre, United Kingdom (NOC).

Processed EM122 multibeam bathymetry survey at Whittard Canyon during cruise DY166: Processing by BODC

The multibeam bathymetry grid from Whittard Canyon collected during DY166 was supplied to BODC as a .txt ASCII file. Data were transferred into a common format, a netCDF subset. The following table shows how the variables within the files were mapped to the appropriate BODC parameter codes:

Following transfer, the data are screened visually using BODC's in-house visualisation software and Globe V2.6.0, and any spikes or instrument malfunctions are clearly labelled with quality control flags.

References

Poncelet Cyrille, Billant Gael, Corre Marie-Paule, Saunier Anthony (2025). Globe (GLobal Oceanographic Bathymetry Explorer) Software. SEANOE https://doi.org/10.17882/70460.

Project Information

No Project Information held for the Series

Data Activity or Cruise Information

Cruise

Complete Cruise Metadata Report is available here

Fixed Station Information

Fixed Station Information

Fixed Station - Whittard Canyon - The Canyons Marine Conservation Zone

The Canyons MCZ is located in the far south-west corner of the UK continental shelf, more than 330 km from Land's End, Cornwall. It encompasses the steep part of the shelf break where the seabed drops from a depth of 100 m to the oceanic abyssal plain at 2000 m. It is unique within the context of England's largely shallow seas due to its depth, sea-bed topography and the coral features it contains.

There are two large canyons within the site, which add to its topographic complexity: the Explorer Canyon to the north and the Dangaard Canyon below it. The wider Whittard Canyon area encapsulates the Canyons MCZ and also includes a network of submarine canyons to the West. The MCZ, also known as a Marine Protected Area (MPA), was designated in November 2013 under the Marine and Coastal Access Act (2009). The Canyons MCZ covers an area of 661 km², which extends to approximately 5200 km² when Whittard Canyon is included.

On the northernmost wall of the Explorer Canyon is a patch of live Cold-water coral reef (Lophelia pertusa) and Coral gardens, both of which are a OSPAR threatened and/or declining habitat. This is the only known example of living Cold-water coral reef recorded within England's seas, making it unique in these waters.

Cold-water corals and Coral gardens typically support a range of other organisms. The coral provides a three-dimensional structure and a variety of microhabitats that provide shelter and an attachment surface for other species. Both Cold-water corals and Coral gardens can be long-lived but are extremely slow growing (at about 6 mm a year), making protection important for their conservation. Another reef-forming cold-water coral, Madrepora oculata, is also present in the site.

The variety of deep-sea bed communities present are indicative of the range of substrates found in and around the canyons, including bedrock, biogenic reef, coral rubble, coarse sediment, mud and sand. These biological communities include cold-water coral communities (Lophelia pertusa and Madrepora oculata), Coral gardens, feather star (Leptometra celtica) assemblages and Sea-pen and burrowing megafauna communities (including, burrowing anemone fields, squat lobster (Munida sp.) assemblages, barnacle assemblages and deep-sea sea-pen (Kophobelemnon sp.) fields).

Sampling History

Related Fixed Station activities are detailed in Appendix 1

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:

Appendix 1: Whittard Canyon - The Canyons Marine Conservation Zone

Related series for this Fixed Station are presented in the table below. Further information can be found by following the appropriate links.

If you are interested in these series, please be aware we offer a multiple file download service. Should your credentials be insufficient for automatic download, the service also offers a referral to our Enquiries Officer who may be able to negotiate access.