Metadata Report for BODC Series Reference Number 1103322

• 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

General comments on problems

The Data Originator reports that the winch heave-compensation mechanism was not functioning at depths of less than 100 m wire out. Along with the heavy weather conditions experienced for much of the cruise, this caused already sampled water to re-appear at the CTD sensors. Due to heaving of the CTD, pressure reversals have been identified in both the upcast and downcast for all channels. The top of each upcast has also been flagged because the CTD had finished its profile and was sitting at the surface. Due to the problems highlighted above, the Data Originator recommends that the CTD data are not suitable for detailed physical analyses. However, the profiles are adequate as a broad representation of water column characteristics. These problems affect every variable in all 43 series taken during cruise JC025, however some casts and variables have been affected worse than others. These are mentioned below:

Additional data quality comments for JC025

The top 31 m are missing from the upcast of cast 004. There is also no upcast present at all for cast 005.

Salinity

In many casts the salinity profile is very noisy. This is due to the ship heave and pressure reversals mentioned above. The Data Originator commented that these data should be used for qualitative purposes only.

Dissolved oxygen and oxygen saturation

Oxygen was supersaturated near the surface for all casts. The top seven metres in cast 002, top 16 m in cast 006, top nine metres in cast 010 and top 18 m in cast 039 have been flagged for both dissolved oxygen and oxygen saturation.

PAR

There are high levels of noise for several casts in both upwelling and downwelling irradiance. The noise is mostly associated with pressure reversals and confined to the upcast, however there is also significant noise in the upwelling irradiance for the downcast of cast 035.

Backscatter

There was significant noise in backscatter observed in many casts throughout the cruise. This noise is present in both the upcast and the downcast. The upcast in cast 001 is especially affected by blocks of noise. Significant noise is also present in the downcasts of casts 015, 017 and 019. These data points have not been flagged, but users should treat them with caution. The turbidity meter recorded negative values for the entire lower part of the profiles for casts 41-43. These data cycles have been flagged automatically during the conversion to BODC internal format. The presence of these negative values indicates that the calibration used to obtain the data does not properly account for the water conditions, thus underestimating the parameter. Therefore, all data from the turbidity meter recorded on this cruise should be used with caution.

Chlorophyll

The chlorophyll fluorometer recorded negative values for the entire lower part of the profiles in all casts.These data cycles have been flagged automatically during the conversion to BODC internal format. The presence of these negative values indicates that the calibration used to obtain the data does not properly account for the water conditions, thus underestimating the parameter. Therefore, all data from the chlorophyll fluorometer recorded on this cruise should be used with caution.

Attenuation

The transmissometer recorded negative values for the entire lower part of the profiles for casts 41-43. These data cycles have been flagged automatically during the conversion to BODC internal format. The presence of these negative values indicates that the calibration used to obtain the data does not properly account for the water conditions, thus underestimating the parameter. Therefore, all data from the transmissometer recorded on this cruise should be used with caution.

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

Sea-Bird Dissolved Oxygen Sensor SBE 43 and SBE 43F

The SBE 43 is a dissolved oxygen sensor designed for marine applications. It incorporates a high-performance Clark polarographic membrane with a pump that continuously plumbs water through it, preventing algal growth and the development of anoxic conditions when the sensor is taking measurements.

Two configurations are available: SBE 43 produces a voltage output and can be incorporated with any Sea-Bird CTD that accepts input from a 0-5 volt auxiliary sensor, while the SBE 43F produces a frequency output and can be integrated with an SBE 52-MP (Moored Profiler CTD) or used for OEM applications. The specifications below are common to both.

Specifications

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

Instrument Description

CTD Unit and Auxiliary Sensors

The CTD configuration comprised a Sea-Bird Electronics 9plus system, with accompanying Sea-Bird Electronics 11plus V2 deck unit #11P-34173-0676. The CTD frame was fitted with a Chelsea AQUAtracka MKIII fluorometer, a Sea-Bird 43 dissolved oxygen sensor, a Chelsea MKII Alphatracka 0.25 m path transmissometer, a WET Labs ECO-BBRTD turbidity meter, two Chelsea Technologies Group Photosynthetically Active Radiation (PAR) sensors and two RDI Workhorse 300 kHz Lowered Acoustic Doppler Current Profilers (LADCPs). All instruments were attached to a stainless steel Sea-Bird 32 carousel #32-37898-0518 containing 29 x 20-litre rosette bottles. The table below lists more detailed information about the various sensors.

Sea-Bird Electronics SBE 911 and SBE 917 series CTD profilers

The SBE 911 and SBE 917 series of conductivity-temperature-depth (CTD) units are used to collect hydrographic profiles, including temperature, conductivity and pressure as standard. Each profiler consists of an underwater unit and deck unit or SEARAM. Auxiliary sensors, such as fluorometers, dissolved oxygen sensors and transmissometers, and carousel water samplers are commonly added to the underwater unit.

Underwater unit

The CTD underwater unit (SBE 9 or SBE 9 plus) comprises a protective cage (usually with a carousel water sampler), including a main pressure housing containing power supplies, acquisition electronics, telemetry circuitry, and a suite of modular sensors. The original SBE 9 incorporated Sea-Bird's standard modular SBE 3 temperature sensor and SBE 4 conductivity sensor, and a Paroscientific Digiquartz pressure sensor. The conductivity cell was connected to a pump-fed plastic tubing circuit that could include auxiliary sensors. Each SBE 9 unit was custom built to individual specification. The SBE 9 was replaced in 1997 by an off-the-shelf version, termed the SBE 9 plus, that incorporated the SBE 3 plus (or SBE 3P) temperature sensor, SBE 4C conductivity sensor and a Paroscientific Digiquartz pressure sensor. Sensors could be connected to a pump-fed plastic tubing circuit or stand-alone.

Temperature, conductivity and pressure sensors

The conductivity, temperature, and pressure sensors supplied with Sea-Bird CTD systems have outputs in the form of variable frequencies, which are measured using high-speed parallel counters. The resulting count totals are converted to numeric representations of the original frequencies, which bear a direct relationship to temperature, conductivity or pressure. Sampling frequencies for these sensors are typically set at 24 Hz.

The temperature sensing element is a glass-coated thermistor bead, pressure-protected inside a stainless steel tube, while the conductivity sensing element is a cylindrical, flow-through, borosilicate glass cell with three internal platinum electrodes. Thermistor resistance or conductivity cell resistance, respectively, is the controlling element in an optimized Wien Bridge oscillator circuit, which produces a frequency output that can be converted to a temperature or conductivity reading. These sensors are available with depth ratings of 6800 m (aluminium housing) or 10500 m (titanium housing). The Paroscientific Digiquartz pressure sensor comprises a quartz crystal resonator that responds to pressure-induced stress, and temperature is measured for thermal compensation of the calculated pressure.

Additional sensors

Optional sensors for dissolved oxygen, pH, light transmission, fluorescence and others do not require the very high levels of resolution needed in the primary CTD channels, nor do these sensors generally offer variable frequency outputs. Accordingly, signals from the auxiliary sensors are acquired using a conventional voltage-input multiplexed A/D converter (optional). Some Sea-Bird CTDs use a strain gauge pressure sensor (Senso-Metrics) in which case their pressure output data is in the same form as that from the auxiliary sensors as described above.

Deck unit or SEARAM

Each underwater unit is connected to a power supply and data logging system: the SBE 11 (or SBE 11 plus) deck unit allows real-time interfacing between the deck and the underwater unit via a conductive wire, while the submersible SBE 17 (or SBE 17 plus) SEARAM plugs directly into the underwater unit and data are downloaded on recovery of the CTD. The combination of SBE 9 and SBE 17 or SBE 11 are termed SBE 917 or SBE 911, respectively, while the combinations of SBE 9 plus and SBE 17 plus or SBE 11 plus are termed SBE 917 plus or SBE 911 plus.

Specifications

Specifications for the SBE 9 plus underwater unit are listed below:

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

Chelsea Technologies Group Aquatracka MKIII fluorometer

The Chelsea Technologies Group Aquatracka MKIII is a logarithmic response fluorometer. Filters are available to enable the instrument to measure chlorophyll, rhodamine, fluorescein and turbidity.

It uses a pulsed (5.5 Hz) xenon light source discharging along two signal paths to eliminate variations in the flashlamp intensity. The reference path measures the intensity of the light source whilst the signal path measures the intensity of the light emitted from the specimen under test. The reference signal and the emitted light signals are then applied to a ratiometric circuit. In this circuit, the ratio of returned signal to reference signal is computed and scaled logarithmically to achieve a wide dynamic range. The logarithmic conversion accuracy is maintained at better than one percent of the reading over the full output range of the instrument.

Two variants of the instrument are available, both manufactured in titanium, capable of operating in depths from shallow water down to 2000 m and 6000 m respectively. The optical characteristics of the instrument in its different detection modes are visible below:

* The wavelengths for the turbidity filters are customer selectable but must be in the range 400 to 700 nm. The same wavelength is used in the excitation path and the emission path.

The instrument measures chlorophyll a, rhodamine and fluorescein with a concentration range of 0.01 µg l^-1 to 100 µg l^-1. The concentration range for turbidity is 0.01 to 100 FTU (other wavelengths are available on request).

The instrument accuracy is ± 0.02 µg l^-1 (or ± 3% of the reading, whichever is greater) for chlorophyll a, rhodamine and fluorescein. The accuracy for turbidity, over a 0 - 10 FTU range, is ± 0.02 FTU (or ± 3% of the reading, whichever is greater).

Further details are available from the Aquatracka MKIII specification sheet.

Chelsea Technologies Group ALPHAtracka and ALPHAtracka II transmissometers

The Chelsea Technologies Group ALPHAtracka (the Mark I) and its successor, the ALPHAtracka II (the Mark II), are both accurate (< 0.3 % fullscale) transmissometers that measure the beam attenuation coefficient at 660 nm. Green (565 nm), yellow (590 nm) and blue (470 nm) wavelength variants are available on special order.

The instrument consists of a Transmitter/Reference Assembly and a Detector Assembly aligned and spaced apart by an open support frame. The housing and frame are both manufactured in titanium and are pressure rated to 6000 m depth.

The Transmitter/Reference housing is sealed by an end cap. Inside the housing an LED light source emits a collimated beam through a sealed window. The Detector housing is also sealed by an end cap. A signal photodiode is placed behind a sealed window to receive the collimated beam from the Transmitter.

The primary difference between the ALPHAtracka and ALPHAtracka II is that the Alphatracka II is implemented with surface-mount technology; this has enabled a much smaller diameter pressure housing to be used while retaining exactly the same optical train as in the Mark I. Data from the Mark II version are thus fully compatible with that already obtained with the Mark I. The performance of the Mark II is further enhanced by two electronic developments from Chelsea Technologies Group - firstly, all items are locked in a signal nulling loop of near infinite gain and, secondly, the signal output linearity is inherently defined by digital circuitry only.

Among other advantages noted above, these features ensure that the optical intensity of the Mark II, indicated by the output voltage, is accurately represented by a straight line interpolation between a reading near full-scale under known conditions and a zero reading when blanked off.

For optimum measurements in a wide range of environmental conditions, the Mark I and Mark II are available in 5 cm, 10 cm and 25 cm path length versions. Output is default factory set to 2.5 volts but can be adjusted to 5 volts on request.

Further details about the Mark II instrument are available from the Chelsea Technologies Group ALPHAtrackaII specification sheet.

Chelsea Technologies Photosynthetically Active Radiation (PAR) Irradiance Sensor

This sensor was originally designed to assist the study of marine photosynthesis. With the use of logarithmic amplication, the sensor covers a range of 6 orders of magnitude, which avoids setting up the sensor range for the expected signal level for different ambient conditions.

The sensor consists of a hollow PTFE 2-pi collector supported by a clear acetal dome diverting light to a filter and photodiode from which a cosine response is obtained. The sensor can be used in moorings, profiling or deployed in towed vehicles and can measure both upwelling and downwelling light.

Specifications

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

WETLabs Single-angle Backscattering Meter ECO BB

An optical scattering sensor that measures scattering at 117°. This angle was determined as a minimum convergence point for variations in the volume scattering function induced by suspended materials and water. The measured signal is less determined by the type and size of the materials in the water and is more directly correlated to their concentration.

Several versions are available, with minor differences in their specifications:

• ECO BB(RT)provides analog or RS-232 serial output with 4000 count range
• ECO BB(RT)D adds the possibility of being deployed in depths up to 6000 m while keeping the capabilities of ECO BB(RT)
• ECO BB provides the capabilities of ECO BB(RT) with periodic sampling
• ECO BBB is similar to ECO BB but with internal batteries for autonomous operation
• ECO BBS is similar to ECO BB but with an integrated anti-fouling bio-wiper
• ECO BBSB has the capabilities of ECO BBS but with internal batteries for autonomous operation

Specifications

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

Originator's Data Processing for CTD casts on JC025

Sampling Strategy

A total of 43 CTD casts were taken during cruise JC025 from 02 to 27 July 2008 in the Celtic Sea. 40 casts were taken in the area of Jones Bank, with the remaining 3 taken on the shelf edge. Rosette bottles were fired throughout the water column in order to obtain independent salinity and chlorophyll samples for calibration against CTD sensors. Water bottle samples were taken to be analysed for inorganic nutrients, chlorophyll, nitrogen uptake, phytoplankton and other pelagic microbes by the Scottish Association for Marine Science (SAMS). Water samples were taken at six depths for primary productivity, equivalent to 100%, 50%, 25%, 15%, 3% and 1% of surface light intensity. These samples were analysed by Napier University.

Data Processing

The raw CTD files were recorded using Sea-Bird Electronics Seasave Win32 recording software (version 5.39a) and processed using the Sea-Bird Electronics SeaSoft data processing software (version 5.37b). The binary (.DAT) files were converted to engineering units and ASCII (.CNV) files using the DATCNV program. To compensate for the effects of the thermal mass of the conductivity cell, the data files were passed through the SeaSoft CELLTM program using = 0.03 and tau = 7, typical values for this model of this CTD given by the Sea-Bird literature. Salinity was then calculated using the DERIVE program and the raw CTD data acquired at 24 Hz was binned to 2 Hz by National Marine Facilities (NMF) using the BINAVERAGE program.

Field Calibrations

Full details of these calibrations can be found in pages 19 to 21 of the JC025 cruise report.

Salinity

A total of 47 samples were collected from CTD casts for analysis by NMF using a laboratory Autosal against standard seawater. Both primary and secondary salinity measurements made by the CTD were found to have an average offset of 0.0004 ± 0.0010 (i.e. Autosal salinity = CTD salinity + 0.0004).

Chlorophyll

78 independent chlorophyll samples, taken from 40 casts in the area of Jones Bank, were used to calibrate the CTD fluorometer data. For each sample, 500 ml of seawater was filtered through both GF/F filters (0.4 µm) and size fractionated polycarbonate filters of 20 and 2 µm before being stored frozen in Eppendorf tubes. Pigment extraction was performed overnight in the dark at 4 °C in 90% acetone. Next, the samples were sonicated and centrifuged to release the pigment into solution. Chlorophyll a concentrations were determined from solution using a Turner Designs Trilogy fluorometer.

Comparisons were then carried out against the CTD fluorometer data using linear regression analyses. The results of the linear regressions showed that the 20 and 2 µm samples were more suitable as a calibration dataset than the GF/F data ( R²=0.6, RMS = 0.15 for fractionated data against R²=0.27, RMS = 0.2 for GF/F data).

The fractionated filter data was therefore used as the calibration dataset. Three data points were deemed to be outliers and removed from the analysis. A calibration equation was derived from a linear regression, based on 75 observations, as follows: calibrated chlorophyll = 0.88 x CTD chlorophyll - 0.12 µg l^-1. The R² for the calibration was 0.72 with a RMS of 0.12.

CTD casts 041 to 043 were taken at the shelf edge. In the experience of the Data Originator, fluorescence characteristics at the shelf edge are markedly different compared to the rest of the Celtic Sea. This means that the chlorophyll calibration cannot be extended to these casts and they must be regarded as uncalibrated.

Processing of JC025 CTD data by BODC

The data arrived at BODC in 43 ASCII format .CNV files representing all of the CTD casts taken during the cruise. The raw data files were inspected and all data points recorded when the CTD was sat on deck or underwent a surface soak were removed. They were reformatted to the internal BODC format using transfer function 357. The following table shows how the variables within the .CNV files were mapped to appropriate BODC parameter codes:

General Data Screening carried out by BODC

BODC screen both the series header qualifying information and the parameter values in the data cycles themselves.

Header information is inspected for:

• Irregularities such as unfeasible values
• Inconsistencies between related information, for example:
  • Times for instrument deployment and for start/end of data series
  • Length of record and the number of data cycles/cycle interval
  • Parameters expected and the parameters actually present in the data cycles
• Originator's comments on meter/mooring performance and data quality

Documents are written by BODC highlighting irregularities which cannot be resolved.

Data cycles are inspected using time or depth series plots of all parameters. Currents are additionally inspected using vector scatter plots and time series plots of North and East velocity components. These presentations undergo intrinsic and extrinsic screening to detect infeasible values within the data cycles themselves and inconsistencies as seen when comparing characteristics of adjacent data sets displaced with respect to depth, position or time. Values suspected of being of non-oceanographic origin may be tagged with the BODC flag denoting suspect value; the data values will not be altered.

The following types of irregularity, each relying on visual detection in the plot, are amongst those which may be flagged as suspect:

• Spurious data at the start or end of the record.
• Obvious spikes occurring in periods free from meteorological disturbance.
• A sequence of constant values in consecutive data cycles.

If a large percentage of the data is affected by irregularities then a Problem Report will be written rather than flagging the individual suspect values. Problem Reports are also used to highlight irregularities seen in the graphical data presentations.

Inconsistencies between the characteristics of the data set and those of its neighbours are sought and, where necessary, documented. This covers inconsistencies such as the following:

• Maximum and minimum values of parameters (spikes excluded).
• The occurrence of meteorological events.

This intrinsic and extrinsic screening of the parameter values seeks to confirm the qualifying information and the source laboratory's comments on the series. In screening and collating information, every care is taken to ensure that errors of BODC making are not introduced.

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 3: Shelf and Coastal Processes

Over the next 20 years, UK local marine environments are predicted to experience ever-increasing rates of change - including increased temperature and seawater acidity, changing freshwater run-off, changes in sea level, and a likely increase in flooding events - causing great concern for those charged with their management and protection. The future quality, health and sustainability of UK marine waters require improved appreciation of the complex interactions that occur not only within the coastal and shelf environment, but also between the environment and human actions. This knowledge must primarily be provided by whole-system operational numerical models, able to provide reliable predictions of short and long-term system responses to change.

However, such tools are only viable if scientists understand the underlying processes they are attempting to model and can interpret the resulting data. Many fundamental processes in shelf edge, shelf, coastal and estuarine systems, particularly across key interfaces in the environment, are not fully understood.

Theme 3 addresses the following broad questions:

• How do biological, physical and chemical processes interact within shelf, coastal and estuarine systems, particularly at key environmental interfaces (e.g. coastline, sediment-water interface, thermocline, fronts and the shelf edge)?
• What are the consequences of these interactions on the functioning of the whole coastal system, including its sensitivity and/or resilience to change?
• Ultimately, what changes should be expected to be seen in the UK coastal environment over the next 50 years and beyond and how might these changes be transmitted into the open ocean?

Within Oceans 2025, Theme 3 will develop the necessary understanding of interacting processes to enable the consequences of environmental and anthropogenic change on UK shelf seas, coasts and estuaries to be predicted. Theme 3 will also provide knowledge that can improve the forecasting capability of models being used for the operational management of human activities in the coastal marine environment. Theme 3 is therefore directly relevant to all three of NERC's current strategic priorities; Earth's Life-Support Systems, Climate Change, and Sustainable Economies

The official Oceans 2025 documentation for this Theme is available from the following link: Oceans 2025 Theme 3

Weblink: http://www.oceans2025.org/

Oceans 2025 Theme 3, Work Package 3.2: Horizontal Patchiness in Vertical Mixing in Stratified Shelf Seas

In this Work Package, the Proudman Oceanographic Laboratory (POL) aim to address vertical mixing processes at the thermocline that are either poorly understood or have inadequate parameterisations in models. This is important because, as a boundary to vertical mixing, the thermocline affects much of the ecology and biochemistry of seasonally-stratifying shelf seas. Horizontal patchiness of vertical mixing is now known to be driven by varying seabed topography, indicating a need for a non-hydrostatic approach. This work is an expansion of the research carried out by POL during project Physical-Biological Control of New Production within the Seasonal Thermocline.

The specific objectives of Work Package 3.2 are:

• Quantify discrepancies between the Proudman Oceanographic Laboratory Coastal Ocean Modelling System (POLCOMS) numerical model and observations of thermocline depths/strengths and diapycnal fluxes.
• Determine the causes of these discrepancies in terms of modelled and observed responses to meteorological forcing and in terms of the potential for patchy internal mixing.
• Quantify the importance of non-hydrostatic processes at the thermocline over typical shelf topographies.
• Carry out ship-based process studies focusing on the patchiness of mixing through the shelf thermocline.
• Quantify the consequences of thermocline patchiness over a whole shelf sea, alongside recommendations for process, bathymetry, and model resolution required to simulate the more important consequences.

More detailed information on this Work Package is available at pages 7 - 8 of the official Oceans 2025 Theme 3 document: Oceans 2025 Theme 3

Weblink: http://www.oceans2025.org/

Cruise Schedule

Moorings

Data Activity or Cruise Information

Cruise

Complete Cruise Metadata Report is available here

Fixed Station Information

Fixed Station Information

Oceans 2025 WP3.2: Fixed Station MS4

Station MS4 is located at 49° 45.00'N, 7° 40.00'W in the Celtic Sea and has a water depth of 110 m. This station was visited as part of the fieldwork carried out for Oceans 2025 Theme 3, Work Package 3.2: Horizontal Patchiness in Vertical Mixing in Stratified Shelf Seas. Activities were carried out at site MS4 during cruise JC025 from 04 July 2008 to 23 July 2008. The exact position is visible below.

Position of Fixed Stations sampled during JC025

Sampling History for MS4

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: Oceans 2025 WP3.2: Fixed Station MS4

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.