Metadata Report for BODC Series Reference Number 1839437
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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Parameters |
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Problem Reports
No Problem Report Found in the Database
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
RD Instruments- Ocean Surveyor 150kHz Vessel mounted ADCP.
Long-Range Mode | ||
---|---|---|
Vertical Resolution Cell Size3 | Max. Range (m)1 | Precision (cm/s)2 |
4m | 325 - 350 | 30 |
8m | 375 - 400 | 19 |
High-Precision Mode | ||
Vertical Resolution Cell Size3 | Max.Range (m)1 | Precision (cm/s)2 |
4m | 200 - 250 | 12 |
8m | 220 - 275 | 9 |
1 Ranges at 1 to 5 knots ship speed are typical and vary with situation.
2 Single-ping standard deviation.
3 User's choice of depth cell size is not limited to the typical values specified.
Profile Parameters
- Velocity long-term accuracy (typical): ±1.0%, ±0.5cm/s
- Velocity range: -5 to 9m/s
- # of depth cells: 1 - 128
- Max ping rate: 1.5
Bottom Track
Maximum altitude (precision <2cm/s): 600m
Echo Intensity Profile
Dynamic range: 80dB
Precision: ±1.5dB
Transducer & Hardware
Beam angle: 30°
Configuration: 4-beam phased array
Communications: RS-232 or RS-422 hex-ASCII or binary output at 1200 - 115,200 baud
Output power: 1000W
Standard Sensors
Temperature (mounted on transducer)
- Range: -5° to 45°C
- Precision: ±0.1°C
- Resolution: 0.03°
Environmental
Operating temperature: -5° to 40°C (-5° to 45°C)*
Storage temperature: -30° to 50°C (-30° to 60°C)*
*later instruments have greater range.
Web Page
Further details can be found in the manufacturer's website or in the specification sheet.
Shelf Sea Biogeochemistry (SSB) RRS Discovery cruise DY017 75kHz and 150kHz Shipboard ADCP BODC Processing
The data were converted from Matlab structures into BODC internal format, a netCDF subset, to allow use of in-house visualisation tools.
As well as the uncorrected data which was transferred, the originator provided data corrected for tides, however they noted that although it improves the data in some regions it adds effectively random variability to an already poorly understood system and should not be used. Therefore, it has not been transferred.
Null cycles were deleted.
The table below shows the mapping of originators variables to BODC Parameter codes.
Originator's variable | Units | BODC Parameter Code | Units | Comments |
---|---|---|---|---|
lon | Degrees | ALONGP01 | Degrees | - |
lat | Degrees | ALATGP01 | Degrees | - |
depth | m | DBINAA01 | m | - |
vel_east | m/s | LCEWAS01 | cm/s | Values converted by multiplication by 100. |
vel_north | m/s | LCNSAS01 | cm/s | Values converted by multiplication by 100. |
ship_vel_east | m/s | APEWGP01 | cm/s | Values converted by multiplication by 100. |
ship_vel_north | m/s | APNSGP01 | cm/s | Values converted by multiplication by 100. |
- | - | BINNUMBR | number | Added during transfer to reflect the number of bins in the file |
Reformatted data were visually checked using the in-house editor EDSERPLO. No data values were edited or deleted. Flagging was achieved by modification of the associated quality control flag to 'M' for suspect values and 'N' for nulls.
Once quality control screening was complete, the data were archived in the BODC National Oceanographic Database and the associated metadata were loaded into an ORACLE Relational Database Management System.
Shelf Sea Biogeochemistry (SSB) RRS Discovery cruise DY017 75kHz and 150kHz Shipboard ADCP Originator data processing
The following was taken from the DY017 cruise report. For more detailed information please refer to the cruise report (Painter, 2015)
The 75kHz and 150 kHz Ocean Surveyor ADCPs were mounted on the ship's hull in a forward - aft configuration, approximately 6 m below the waterline. Their nominal rotation relative to the centreline of the ship is -45°. Positional and attitude information is provided via a PosMV multi-receiver GPS attitude sensor.
ADCP setup
Variable | 75kHz | 150kHz |
---|---|---|
Number of Bins | 60 | 96 |
Bin size | 16m | 4m |
Blank distance | 8m | 4m |
Transducer depth | 6m | 6m |
Processing mode | low-resolution (long range) | low-resolution (long range) |
Post-processing
The RDI proprietary software VMDAS was used to configure the ADCP and perform velocity mapping to the reference frame of the vessel. Bottom tracking was enabled for the majority of the cruise. Most of the post-processing was done using a set of Matlab routines, see the cruise report for more detail.
Quality Report
On arrival on Discovery it was found that the OS150 ADCP was still configured with factory settings. The ADCP settings were mostly copied from the OS75 machine, but the ADCP alignment in the hull was set at 0° initially rather than -45° as with the OS75. On post-processing the data it was discovered that the correct misalignment was in fact -45° as well. The Matlab routines are able to correct for this
Early in the cruise it was discovered that the fourth beam of the OS75 was not working. With the VMDAS display set to 'real-time', this was seen as a persistent absence of velocity returns (occasional gaps are normal and are averaged out). The software can perform '3-beam solutions' but parts of the QC in the Matlab routines had to be suppressed as they check for a threshold 'percentage good' in all beams. After email discussion with NOC, the deck unit handling the OS75 feed was swapped with a spare, which rectified the problem.
During the cruise it was noted that when 'bottom tracking' was switched off, virtual echo data from below the seabed were not automatically removed. For this version, the seabed was defined using the ship's lat/lon and the Gebco 1 min grid. Any data falling below the estimated seabed depth was removed.
In addition, it was noted that data from the 150 kHz ADCP became degraded at 150 - 200 m depth but sporadically penetrated to 400 m (fig. 3). Data from below 200 m could result in misleading velocity estimates if unwittingly included in calculations, so were rejected below this depth.
References
Painter, S.C. 2015. RRS Discovery Cruise DY017, 20 Oct - 06 nov 2014. Outer Hebrides process cruise report. Southampton, UK: National Oceanography Centre, Southampton, 118pp. (National Oceanography Centre Cruise Report, No 29).
Project Information
Shelf Sea Biogeochemistry (SSB) Programme
Shelf Sea Biogeochemistry (SSB) is a £10.5 million, six-year (2011-2017) research programme, jointly funded by the Natural Environment Research Council (NERC) and the Department for Environment, Food and Rural Affairs (DEFRA). The aim of the research is to reduce the uncertainty in our understanding of nutrient and carbon cycling within the shelf seas, and of their role in global biogeochemical cycles. SSB will also provide effective policy advice and make a significant contribution to the Living with Environmental Change programme.
Background
The Shelf Sea Biogeochemistry research programme directly relates to the delivery of the NERC Earth system science theme and aims to provide evidence that supports a number of marine policy areas and statutory requirements, such as the Marine Strategy Framework Directive and Marine and Climate Acts.
The shelf seas are highly productive compared to the open ocean, a productivity that underpins more than 90 per cent of global fisheries. Their importance to society extends beyond food production to include issues of biodiversity, carbon cycling and storage, waste disposal, nutrient cycling, recreation and renewable energy resources.
The shelf seas have been estimated to be the most valuable biome on Earth, but they are under considerable stress, as a result of anthropogenic nutrient loading, overfishing, habitat disturbance, climate change and other impacts.
However, even within the relatively well-studied European shelf seas, fundamental biogeochemical processes are poorly understood. For example: the role of shelf seas in carbon storage; in the global cycles of key nutrients (nitrogen, phosphorus, silicon and iron); and in determining primary and secondary production, and thereby underpinning the future delivery of many other ecosystem services.
Improved knowledge of such factors is not only required by marine policymakers; it also has the potential to increase the quality and cost-effectiveness of management decisions at the local, national and international levels under conditions of climate change.
The Shelf Sea Biogeochemistry research programme will take a holistic approach to the cycling of nutrients and carbon and the controls on primary and secondary production in UK and European shelf seas, to increase understanding of these processes and their role in wider biogeochemical cycles. It will thereby significantly improve predictive marine biogeochemical and ecosystem models over a range of scales.
The scope of the programme includes exchanges with the open ocean (transport on and off the shelf to a depth of around 500m), together with cycling, storage and release processes on the shelf slope, and air-sea exchange of greenhouse gases (carbon dioxide and nitrous oxide).
Further details are available on the SSB website.
Participants
15 different organisations are directly involved in research for SSB. These institutions are
- Centre for Environment, Fisheries and Aquaculture Science (Cefas)
- Meteorological Office
- National Oceanography Centre (NOC)
- Plymouth Marine Laboratory (PML)
- Scottish Association for Marine Science (SAMS) / Scottish Marine Institute (SMI)
- University of Aberdeen
- University of Bangor
- University of East Anglia (UEA)
- University of Edinburgh
- University of Essex
- University of Liverpool
- University of Oxford
- Plymouth University
- University of Portsmouth
- University of Southampton
In addition, there are third party institutions carrying out sampling work for SSB, but who are not involved in the programme itself. These are:
- The Agri-Food and Biosciences Institute (AFBI)
- Irish Marine Institute (MI)
- Marine Science Scotland (MSS)
Research details
Overall, five Work Packages have been funded by the SSB programme. These are described in brief below:
-
Work Package 1: Carbon and Nutrient Dynamics and Fluxes over Shelf Systems (CaNDyFloSS).
This work package aims to perform a comprehensive study of the cycling of nutrients and carbon throughout the water column over the whole north-west European shelf. This will allow the fluxes of nutrients and carbon between the shelf and the deep ocean and atmosphere to be quantified, establishing the role of the north-west European continental shelf in the global carbon cycle. -
Work Package 2: Biogeochemistry, macronutrient and carbon cycling in the benthic layer.
This work package aims are to map the sensitivity and status of seabed habitats, based on physical conditions, ecological community structure and the size and dynamics of the nitrogen and carbon pools found there. This information will be used, in conjunction with some laboratory-based work, to generate an understanding of the potential impacts on the benthic community as a result of changing environmental conditions, such as rising CO2 levels. -
Work Package 3: The supply of iron from shelf sediments to the ocean.
The research for this work package addresses the question of how currents, tides, weather and marine chemistry allow new iron to be transported away from the shallow shelf waters around the United Kingdom (UK), to the nearby open ocean. This will ultimately allow an improved understanding of how the transport of iron in shelf waters and shelf sediments influences phytoplankton growth in open oceans. This in turn improves the understanding of carbon dioxide uptake by phytoplankton. -
Work Package 4: Integrative modelling for Shelf Seas Biogeochemistry.
The aim of this work package is the development of a new shelf seas biogeochemical model system, coupled to a state of the art physical model, that is capable of predicting regional impacts of environmental change of timescales from days to decades. It is envisaged that the combination of predictive tools and new knowledge developed in this work package will underpin development and implementation of marine policy and marine forecasting systems. - Work Package 5: Data synthesis and management of marine and coastal carbon (DSMMAC).
This work package is funded by Defra and is also known by the name 'Blue Carbon'. The aim is to provide a process-based, quantitative assessment of the role of UK coastal waters and shelf seas in carbon storage and release, using existing data and understanding, and also emerging results from SSB fieldwork, experiments and modelling. Particular emphasis will be given to processes that may be influenced by human activities, and hence the opportunity for management interventions to enhance carbon sequestration.
Fieldwork and data collection
The campaign consists of the core cruises in the table below, to the marine shelf (and shelf-edge) of the Celtic Sea on board the NERC research vessels RRS Discovery and RRS James Cook. These cruises will focus on the physics and biogeochemistry of the benthic and pelagic zones of the water column, primarily around four main sampling sites in this area.
Cruise identifier | Research ship | Cruise dates | Work packages |
---|---|---|---|
DY008 | RRS Discovery | March 2014 | WP 2 and WP 3 |
JC105 | RRS James Cook | June 2014 | WP 1, WP 2 and WP 3 |
DY026 | RRS Discovery | August 2014 | WP1, WP 2 and WP 3 |
DY018 | RRS Discovery | November - December 2014 | WP 1 and WP 3 |
DY021 (also known as DY008b) | RRS Discovery | March 2015 | WP 2 and WP 3 |
DY029 | RRS Discovery | April 2015 | WP 1 and WP 3 |
DY030 | RRS Discovery | May 2015 | WP 2 and WP 3 |
DY033 | RRS Discovery | July 2015 | WP 1 and WP 3 |
DY034 | RRS Discovery | August 2015 | WP 2 and WP 3 |
Core cruises will be supplemented by partner cruises led by Cefas, MI, MSS, Bangor University and AFBI, spanning the shelf seas and shelf-edges around United Kingdom and Republic of Ireland.
Activities will include coring, Conductivity Temperature and Depth (CTD) deployments, Acoustic Doppler Current Profilers (ADCP) surveys, moorings and wire-walker deployments, benthic lander observatories, autonomous gliders and submersible surveys, Marine Snow Catcher particulate matter analysis, plankton net hauls, in-situ sediment flume investigations and laboratory incubations with core and sea water samples.
Data Activity or Cruise Information
Cruise
Cruise Name | DY017 |
Departure Date | 2014-10-20 |
Arrival Date | 2014-11-06 |
Principal Scientist(s) | Stuart Painter (National Oceanography Centre, Southampton) |
Ship | RRS Discovery |
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 |