Metadata Report for BODC Series Reference Number 753708
Metadata Summary
Problem Reports
Data Access Policy
Narrative Documents
Project Information
Data Activity or Cruise Information
Fixed Station Information
BODC Quality Flags
Metadata Summary
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Problem Reports
No Problem Report Found in the Database
Data Access Policy
Public domain 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.
The recommended acknowledgment is
"This study uses data from the data source/organisation/programme, provided by the British Oceanographic Data Centre and funded by the funding body."
Narrative Documents
Instrument Description
Water velocities were measured using a vessel mounted Teledyne RDI 150 kHz ADCP (VMADCP). The transducer unit was installed in the hull 1.75 m to port of the keel, 33 m aft of the bow at the waterline and at an approximate depth of 5 m. Data were logged using IBM Data Acquisition Software (DAS) version 2.48 with profiler software 17.10. Position and ship velocities were derived from the Bestnav system which is an assembly of multiple GPS signals, including the gyronmea and em-log stream in order to calculate the best possible position, speed, heading, pitch and roll of the ship. Further information on VMADCP instrumentation can be found in the cruise report on p89 and on p133. Further information on navigational instrumentation can be found from p84 of the cruise report.
RD Instruments 150kHz Narrow Band Acoustic Doppler Current Profiler
Specifications
| Water velocity measurements relative to the ADCP | |
|---|---|
| Accuracy (long term) | 0.5 % of measured velocity ± 0.5 cm/s |
| Statistical uncertainty for one ping (cm/s) | Depth cell length of 4, 8, 16 m = 26, 13, 6.5 respectively (for horizontal velocities using the standard transducer) |
| Ping rate (pings per second) | 2 (100 pings averaged in ADCP) |
| Maximum profiling range (meters) | 290 |
| Minimum range to start of first depth cell (meters) | 4 |
| Number of depth cells | 8 to 128 |
| Velocity range | ± 0.01 to 9.5 m/s (horizontal) |
| Velocity resolution (cm/s) | 0.25 or 0.125 |
| Velocity measurements relative to the bottom and measurement of bottom depth | |
| Accuracy | 0.5% of measured velocity ± 0.5 cm/s |
| Statistical uncertainty of one ping (percent of measured velocity) | 3.5 (for horizontal velocities using the standard transducer) |
| Ping rate (pings per second) | 0.9 (100 pings averaged in ADCP) |
| Depth range | 290 (the maximum depth range can be up to 1.5 times greater than specified) |
| Bottom depth resolution (meters) | 4 |
| Velocity range | ± 0.01 to 9.5 m/s (horizontal) |
| Velocity resolution (cm/s) | 0.25 or 0.125 |
| Measurement of echo intensity | |
| Accuracy (with temperature correction) | Before calibration : ± 8 dB, After calibration: ± 3 dB |
| Statistical uncertainty for one ping | Approximately ± 5 dB |
| Ping rate (pings per second) | 2 (100 pings averaged in ADCP) |
| Profiling range (meters less than for water velocity measurement) | 64 |
| Number of depth cells | 8 to 128 |
| Dynamic range | 80 dB |
| Resolution | 0.45 dB typical (temperature/system dependent) |
| Data communication | |
| Interface | Modified RS-232/422 serial at baud rates of 300-19,200 |
| Data format | Binary (8-bit) or ASCII (76-character) lines separated by a carriage return/line feed. |
| Data storage capacity | 2 MB (standard); expandable to 40 MB in 1 and/or 2 MB increments |
| Power requirements | |
| ADCP electronics | Voltage range (VDC) 6-12; Standby current (amps) 0.0002; Operate current (amps) 0.24; Peak current (amps) 0.5 |
| transmit and EPROM recorder | Voltage range (VDC) 20-40; Standby current (amps) 0.0001; Operate current (amps) 0.10; Peak current (amps) 2.0 |
| CTD sensors | Voltage range (VDC) 12-20; Standby current (amps) 0.0001; Operate current (amps) 0.022; Peak current (amps) 0.05 |
| Temperature sensor | |
| Accuracy | ± 0.2°C |
| Time constant | Approximately 2 minutes |
| Range | -5° to 45°C |
| Resolution | 0.012°C |
| Environmental | |
| Operating temperature | -5°C to 40°C |
| Humidity | Must be non-condensing |
| Depth capability | 35 meters (transducer only) |
| Physical characteristics | |
| Weight in air | 67.6 kg |
| Weight in water | 25.0 |
| Diameter | 45.9 cm |
| Length | 141.4 cm |
BODC Processing
The data arrived at BODC in 23 PSTAR format files (nomenclature = adp321##.abs) representing all the data collected during the cruise. These were reformatted to the internal QXF format using BODC transfer function 389. The following table shows how the variables within the PSTAR files were mapped to appropriate BODC parameter codes:
| Originator's Variable | Units | Description | BODC Parameter Code | Units | Comment |
|---|---|---|---|---|---|
| time | sec | Time | - | - | automatically transferred |
| bindepth | m | Bin depth relative to sea surface | DBINAA01 | m | |
| evencal | cm s-1 | Eastward velocity measured by ADCP (calibrated) | LREWAS01 | cm s-1 | |
| nvelcal | cm s-1 | Northward velocity measured by ADCP (calibrated) | LRNSAS01 | cm s-1 | |
| ve | cm s-1 | Ship's eastward velocity | APEWGP01 | cm s-1 | derived from Bestnav data stream |
| vn | cm s-1 | Ship's northward velocity | APNSGP01 | cm s-1 | derived from Bestnav data stream |
| absve | cm s-1 | Absolute eastward velocity of the water column by ADCP | LCEWAS01 | cm s-1 | |
| absvn | cm s-1 | Absolute northward velocity of the water column by ADCP | LCNSAS01 | cm s-1 | |
| velvert | cm s-1 | Upward current velocity of the water column by ADCP | LRZAAS01 | cm s-1 | |
| velerr | cm s-1 | Current velocity error in the water column by ADCP | LERRAS01 | cm s-1 | |
| ampl | decibel | Signal return amplitude by ADCP | ASAMSP01 | decibel | |
| good | % | % good by ADCP | PCGDAP01 | % | |
| a-ghdg | degrees | ASHTECH gyro-heading difference | - | - | Not transferred - derived variable |
| lat | decimal degrees | Latitude north from Bestnav data stream | ALATGP01 | decimal degrees | |
| lon | decimal degrees | Longitude east from Bestnav data stream | ALONGP01 | decimal degrees | |
| distrun | km | Distance run | - | - | Not derived - calculated from Bestnav data stream |
Following the originator's advice, the reformatted data were subsequently amended by subtracting 5 m from the original bin depths (to make the first bin depth centre equal to 11 m, instead of 16 m). This was because the originator had identified a mistake in the labelling of bin depths. The adjustment did not effect the velocities measured. The data were then visualised using the in-house EDSERPLO software. Suspect data were marked by adding an appropriate quality control flag. Missing data were marked by setting the data to an appropriate absent data value and absent data quality control flag.
Originator's Data Processing
Sampling Strategy
The VMADCP was logged and operated throughout the cruise and was configured to sample over 120 bins of 4 m depth at 120 second intervals between 25/07/2007 11:51 to 26/07/2007 08:34 and 96 bins of 4 m depth at 120 second intervals from 26/07/2007 09:00. The blank beyond transmit and pulse length were 4 m. Data were reduced to 2 minute ensembles. The instrument was operated in water tracking mode with the exception of the cruise start (between 25/07/2007 11:51 to 26/07/2007 08:34) when the ADCP was logged in bottom tracking mode to enable a calibration. Further information on sampling strategy can be found in the cruise report on p132.
Originator's Data Processing
Logged data were transferred daily (approximately) to the PSTAR processing system where resulting files were read into PSTAR format, calibrated, corrected for the ship's movement and quality controlled using NOCS-generated Unix scripts. Full processing details can be found in the cruise report from p133.
Field Calibrations
Calibration was obtained in bottom track mode with an offset angle = 0°.
Φ (misalignment angle) = -14.4°
A (scaling factor) = 0.9683
Further information on calibration of the VMADCP can be found on p134 of the cruise report.
Project Information
Oceans 2025 - The NERC Marine Centres' Strategic Research Programme 2007-2012
Who funds the programme?
The Natural Environment Research Council (NERC) funds the Oceans 2025 programme, which was originally planned in the context of NERC's 2002-2007 strategy and later realigned to NERC's subsequent strategy (Next Generation Science for Planet Earth; NERC 2007).
Who is involved in the programme?
The Oceans 2025 programme was designed by and is to be implemented through seven leading UK marine centres. The marine centres work together in coordination and are also supported by cooperation and input from government bodies, universities and other partners. The seven marine centres are:
- National Oceanography Centre, Southampton (NOCS)
- Plymouth Marine Laboratory (PML)
- Marine Biological Association (MBA)
- Sir Alister Hardy Foundation for Marine Science (SAHFOS)
- Proudman Oceanographic Laboratory (POL)
- Scottish Association for Marine Science (SAMS)
- Sea Mammal Research Unit (SMRU)
Oceans2025 provides funding to three national marine facilities, which provide services to the wider UK marine community, in addition to the Oceans 2025 community. These facilities are:
- British Oceanographic Data Centre (BODC), hosted at POL
- Permanent Service for Mean Sea Level (PSMSL), hosted at POL
- Culture Collection of Algae and Protozoa (CCAP), hosted at SAMS
The NERC-run Strategic Ocean Funding Initiative (SOFI) provides additional support to the programme by funding additional research projects and studentships that closely complement the Oceans 2025 programme, primarily through universities.
What is the programme about?
Oceans 2025 sets out to address some key challenges that face the UK as a result of a changing marine environment. The research funded through the programme sets out to increase understanding of the size, nature and impacts of these changes, with the aim to:
- improve knowledge of how the seas behave, not just now but in the future;
- help assess what that might mean for the Earth system and for society;
- assist in developing sustainable solutions for the management of marine resources for future generations;
- enhance the research capabilities and facilities available for UK marine science.
In order to address these aims there are nine science themes supported by the Oceans 2025 programme:
- Climate, circulation and sea level (Theme 1)
- Marine biogeochemical cycles (Theme 2)
- Shelf and coastal processes (Theme 3)
- Biodiversity and ecosystem functioning (Theme 4)
- Continental margins and deep ocean (Theme 5)
- Sustainable marine resources (Theme 6)
- Technology development (Theme 8)
- Next generation ocean prediction (Theme 9)
- Integration of sustained observations in the marine environment (Theme 10)
In the original programme proposal there was a theme on health and human impacts (Theme 7). The elements of this Theme have subsequently been included in Themes 3 and 9.
When is the programme active?
The programme started in April 2007 with funding for 5 years.
Brief summary of the programme fieldwork/data
Programme fieldwork and data collection are to be achieved through:
- physical, biological and chemical parameters sampling throughout the North and South Atlantic during collaborative research cruises aboard NERC's research vessels RRS Discovery, RRS James Cook and RRS James Clark Ross;
- the Continuous Plankton Recorder being deployed by SAHFOS in the North Atlantic and North Pacific on 'ships of opportunity';
- physical parameters measured and relayed in near real-time by fixed moorings and ARGO floats;
- coastal and shelf sea observatory data (Liverpool Bay Coastal Observatory (LBCO) and Western Channel Observatory (WCO)) using the RV Prince Madog and RV Quest.
The data is to be fed into models for validation and future projections. Greater detail can be found in the Theme documents.
Oceans 2025 Theme 2: Marine Biogeochemical Cycles
Marine biogeochemical cycles are the key processes that control the cycling of climate-active gases within the surface ocean; the main transport mechanisms governing the supply of nutrients from deeper waters across the pycnocline; and the flux of material to deep water via the biological carbon pump. The broad aim of this Theme is to improve knowledge of major biogeochemical processes in the surface layer of the Atlantic Ocean and UK shelf seas in order to develop accurate models of these systems. This strategic research will result in predictions of how the ocean will respond to, and either ameliorate or worsen, climate change and ocean acidification.
Theme 2 comprises three Research Units and ten Work Packages. Theme 2 addresses the following pivotal biogeochemical pathways and processes:
- The oceans and shelf seas as a source and sink of climate-active gases
- The importance of the carbon and nitrogen cycles in the regulation of microbial communities and hence export and biogenic gas cycling
- The biological pump and export of carbon into the ocean's interior
- Processes that introduce nutrients into the euphotic zone
- The direct impact of a high CO2 world (acidification) on mixed-layer biogeochemical cycles and feedbacks to the atmosphere via sea/air gas fluxes and the biological pump
- The indirect impact of a high CO2 world (increased stratification and storminess) on the supply of nutrients to the surface layer of the ocean and hence on the biological carbon pump and air-sea gas fluxes
- Cellular processes that mediate calcification in coccolithophores and how these are impacted by environmental change with a focus on elevated CO2 and ocean acidification
- Inter- and intra-specific genetic diversity and inter-specific physiological plasticity in coccolithophores and the consequences of rapid environmental change
The official Oceans 2025 documentation for this Theme can be found using the following link: Oceans 2025 Theme 2
Oceans 2025 Theme 2, Work Package 2.5: Physical Processes and the Supply of Nutrients to the Euphotic Zone
The emphasis behind this Work Package is to gain a better understanding of the ocean's biological carbon pump (OBP), an important process in the global carbon cycle. Small changes in its magnitude resulting from climate change could have significant effects, both on the ocean's ability to sequester CO2 and on the natural flux of marine carbon. This work package is concerned with the effect of physical processes and circulation on nutrient supply to the euphotic zone. Many physical pathways influence nutrient supply, such as winter overturning, Ekman pumping, small-scale turbulent mixing and mesoscale ageostrophic circulations, (of which, eddy pumping is but one example). Increased stratification will change patterns of winter overturning and dampen small-scale mixing. Shifts in wind patterns will perturb Ekman pumping. Changes in gradients of ocean heating and wind-forcing will alter the distribution of potential energy released through baroclinic instability of eddies and fronts. The combined effect of change on total nutrient supply will therefore be complex. Such physically-mediated changes, coupled to changes in aeolian dust deposition, may profoundly alter upper ocean plankton communities, biogeochemical cycling and carbon export.
This Work Package will be primarily coordinated by the National Oceanography Centre, Southampton (NOC). Specific objectives are:
- To determine the relative importance of mechanisms affecting nutrient supply to the photic zone by quantifying them in the three major biomes of the North Atlantic
- To establish how representative process studies are for the basin scale and thus define operators to scale up the individual process study results
- To determine the sensitivity to future climate change of the mechanisms sustaining total nutrient supply to the photic zone over the three major biomes of the North Atlantic
Aspects of this work will link to Oceans 2025 Theme 9 and 10, and Theme 2 WP 2.6.
More detailed information on this Work Package is available from pages 13-15 of the official Oceans 2025 Theme 2 document: Oceans 2025 Theme 2
Weblink: http://www.oceans2025.org/
Oceans 2025 Theme 5: Continental Margins and the Deep Ocean
The deep ocean and the seafloor beneath it are the largest yet least known environments on our planet. They profoundly influence the way in which the Earth reacts to climate change, provide vital resources, and can cause natural catastrophes (with significant risks to the UK). A better understanding of the biodiversity and resource potential of the deep ocean, its geophysics and its complex interactions with the global carbon cycle are all urgently required.
The overall aim of Theme 5 is to deliver coordinated, multidisciplinary research on the functioning of the deep ocean from the photic zone to the sub-seabed, encompassing biology, physics, geology, chemistry and mathematical modelling. Such an integrated deep-sea programme is unique in the UK and will ensure the provision of knowledge essential for underpinning UK policy in conserving marine biodiversity, controlling the effects of global change, managing ocean resources in a sustainable manner, and mitigating the effects of geohazards.
The specific objectives of Theme 5 are:
- To understand the processes controlling the vertical flux of carbon between the base of the photic zone and the seabed and to quantify this flux.
- To quantify fluxes of carbon and fluids from the sub-seabed into the deep ocean and their contribution to global carbon budgets.
- To determine how the carbon flow interacts with deep-ocean pelagic and benthic communities in the open ocean and on the continental slope.
- To investigate how benthic ecosystems on continental margins and in the deep ocean respond to spatial and temporal variation in environmental parameters.
- To understand the causes, frequency and predictability of submarine geohazards.
- To apply scientific knowledge to the sustainable management of the ocean and its resources.
Theme 5 combines two Research Units, on Continental Margins and on the Biochemistry of the Deep Ocean. Ultimately the science of the two activities will be combined, but because the methods of study and the resources needed are largely different, the work has been planned within two groups.
In Continental Margins, the physical processes regulating the transport of sediment is investigated as well as the transport of hydrocarbons and aqueous fluids from the seafloor. The effect of both of these major processes on the landscape ecology of the continental slope will be assessed. In addition, the causes, mechanisms and frequency of submarine geohazards will be studied, particularly those that potentially could have a devastating effect on coastal communities, such as earthquake and landslide-induced tsunamis. Carbon flux from the geosphere into the ocean will be assessed. The information will be used to advise on whole ecosystem management strategies, including policy issues relating to Marine Protected Areas and international treaties on the development of open ocean resources.
In Biogeochemistry of the Deep Ocean, the flux of particles through the 'twilight zone' in order to reduce the large uncertainties in our knowledge of the magnitude of the downward flux in various biogeochemical provinces of the global ocean will be studied. The twilight zone is a large biogeochemical reactor influencing the supply of nutrients to the euphotic zone and the fate of materials consigned to the deep seafloor. Theme 5 will study how zooplankton and microbes repackage and breakdown particles, and how these processes influence carbon transfer. Direct observations and experimental approaches will provide data to drive stoichiometric models of heterotrophic OM utilisation. The impact on the deep-sea benthos of repackaged OM, and the of part of surface production that by-passes twilight zone processes, will be assessed by analysing global patterns and through ROV in situ experimentation. Proven modelling expertise in upper ocean systems will be extended to benthic ecosystems utilising the information generated by bentho-pelagic coupling observations and experimental approaches.
The official Oceans 2025 documentation for this Theme is available from the following link: Oceans 2025 Theme 5
Weblink: http://www.oceans2025.org/
Oceans 2025 Theme 5, Work Package 5.7: Twilight zone dynamics
The surface ocean has been partitioned into discrete functional provinces with particular biogeochemical characteristics. In the Atlantic between 50° N and 50° S, Longhurst (1998) identified six provinces based on physical forcing and primary production. Links between these contrasting production regimes and the underlying deep ocean have not been studied in any detail. Some conceptual approaches, e.g. the bifurcation model, show how surface water production might relate to export, but this is complicated by evidence for strong decoupling between the magnitude of production and particulate export.
Physical dynamics of twilight zone (TZ). We will combine the latest technology and observational techniques to tackle the physically driven pathways to, from and through the deep ocean. On transects, we will test the hypotheses that the TZ is dominated by 3D eddy transports stirring the TZ and exchanging water across the permanent thermocline, while below there is a more quiescent weakly stratified environment dominated by slow mode barotropic flows, interrupted by topographic features over which increased velocity shear leads to enhanced diffusive mixing.
Particle flux through the twilight zone. Our understanding of deep ocean biogeochemistry, community structure and function can be improved by reducing uncertainties in the magnitude of downward flux, and how this changes with depth, region and time. In addition to carbon, this improved understanding must include all limiting elements and the wide variety of complex organic molecules that support life in the deep ocean. Large uncertainties in published data make such quantification a major challenge.
Twilight zone biogeochemistry. For comparison with the microbial community, we will address the role of zooplankton in the TZ by measuring biomass and size spectra using a video plankton camera system and laser optical plankton counter, verified with physical samples from closing nets. Community energy demand will be estimated from the size spectra and allometric relationships to quantify the role of zooplankton in TZ C flux.
Modelling the twilight zone system. For the TZ zone, our modelling approach will focus on particles and their utilisation by zooplankton and bacteria, and on comparing model output with data. Particulate OM will be divided into size classes corresponding to the size spectra of sinking particles, which has consequences for their depth penetration into the ocean. Production and consumption of dissolved OM will also be represented. Both C and N will be included as model currencies, using appropriate stoichiometric models of heterotrophic OM utilisation. Ecosystem models will be tested and analysed in 1D using ecosystem testbeds (Theme 9). The most appropriate will then be used in 3D using the Harvard Ocean Prediction System model, focussed on the fine-scale survey work proposed around the PAP site. Pelagic biology, which provides the export flux, will be developed in this model as part of Theme 2 then extended to the TZ to determine the relationship between TZ processes and variability in the euphotic zone. Climate sensitivity (wind forcing, heating) tests will also be undertaken to examine their impact on export.
More detailed information on this WP is available on page 14-16 of the official Oceans 2025 Theme 5 document: Oceans 2025 Theme 5
Weblink: http://www.oceans2025.org/
References:
Longhurst, A.R. (1998) Ecological Geography of the Sea, Academic Press, 398pp
Data Activity or Cruise Information
Cruise
| Cruise Name | D321 (D321A) |
| Departure Date | 2007-07-24 |
| Arrival Date | 2007-08-23 |
| Principal Scientist(s) | John T Allen (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 |
