Metadata Report for BODC Series Reference Number 1174789

• 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 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

Satlantic OCR 500 series Multispectral Radiometer

The OCR-507 Multispectral Radiometer is a member of Satlantic's line of micro-sensor instruments. The OCR-507 is a complete stand-alone, fully digital optical sensor package capable of generating spectral records of light collected in an ocean environment. The instrument comprises data logging and processing software and is available in two configurations, radiance and irradiance for in-water and in-air applications. The instrument can also be configured as a coupled irradiance and radiance radiometer. Up to seven customer defined discrete optical wavelengths can be utilized with the OCR-507, including standard wavelengths of 400 to 865 nm, or UV wavelengths of 305, 325, 340 and 380 nm.

Two standard, non-isolated, telemetry (data) interfaces are provided with the instrument, each using a different transmission medium. The RS-232 interface provides transmit and receive capabilities whilst the RS-422 interface is for transmittance only. A non-isolated RS-485 interface is also provided for operating the instrument if used in a SatNet networked environment as part of a larger system.

The OCR-507 combines a fully characterized cosine response with custom low fluorescence filters and a sampling rate of 7 to 24 Hz. The instrument is also compatible with Bioshutter anti-biofouling solution.

Specifications for Downwelling Irradiance Configuration

Specifications for Upwelling Radiance Configuration

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

CD173 Satlantic Optical data processing undertaken by BODC

Data were received by BODC as raw data files as well as ASCII and Matlab files for all 4 levels of ProSoft processing. These have all been archived and are available in the originators format on request. BODC have processed the level 3 ASCII files by reformatting to the internal format using established procedures. These data were chosen as they are the most processed data which do not include derived parameters. The data for each deployment were supplied in one file but grouped by parameter. The time channel assigned for each cycle to each group of parameters differed slightly (sub second differences). In order to be consistent it was decided that all data were be assigned the time channel from the E_d parameters. A check was built in to the reformatting software to ensure that the difference between the times used and the times supplied for the other parameter groups was always less than a second. The following table details mapping of variables to BODC parameter codes.

The originator noted that the temperature sensor wasn't working so temperature parameters have not been processed by BODC.

The reformatted data were visualised using BODC in-house software. Suspect data were marked by adding an appropriate quality control flag, and missing data marked by both setting the data to an appropriate absent data value and setting the quality control flag.

CD173 Satlantic Optics data originators processing

Sampling strategy

The free-fall Satlantic Microspectral Muiltprofiler was deployed 59 times during RRS Charles Darwin cruise CD173. The cruise took place between 15 July and 06 August 2005 in the Celtic Sea.

Setup of the instruments

The Satlantic optical profiler was made up of several sensors:

Processing stages

Data were processed by the originator with Satlantic ProSoft software using standard procedures. ProSoft processing is segmented into 4 main levels (extract from the ProSoft user manual):

Originators quality notes

The originator has reported that the temperature sensor wasn't working, hence the water properties have been excluded from the latest reprocessing protocol.

Originators series for cast OB9 did not contain upwelling radiance (L_u) parameters whilst the data from U2Aug3 did not include downwelling irradiance (E_d) parameters.

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

Physical-Biological Control of New Production within the Seasonal Thermocline

This project was a NERC responsive-mode project which was co-funded by the Defence Science and Technology Laboratory and ran from 2003 to 2006. The key institutes and scientists involved were:

Research Aim

The main aim of this research was to investigate the generation and dissipation of turbulence in the thermocline, and to quantify how the resulting mixing (supplying nutrients and controlling the light experienced by the algae) affected the growth of phytoplankton within the sub-surface chlorophyll maximum (SCM).

Research Objectives

The objective of the research was to test the general hypothesis that, in seasonally-stratified shelf waters, temporal and spatial variability of the rate of 'new' production is determined by the degree of coupling between physical and biological processes within the seasonal thermocline. In particular it has been suggested that physiological adaptation by phytoplankton making up the subsurface chlorophyll maximum drives a biological pump for extracting nitrate from the bottom mixed layer that is sensitive to internal mixing and to external climatological factors.

Research Approach

The sampling and experimental strategy was based on established methods for obtaining compatible, high-resolution vertical profiles (alternate CTD and FLY) and sections (SeaSoar) of physical, chemical, and biological parameters, allowing quantification of vertical fluxes and primary production on tidal and internal wave time scales. The cruise schedule (with associated mooring deployments) for the project is below.

Cruise Schedule

Moorings

^* = metres above seabed

Project Outcomes

The main products of the research were:

• The first large scale interdisciplinary study of the dynamic processes that determine the properties of the SCM in NW European shelf waters.
• Substantive advances in quantifying internal mixing in NW European shelf seas, and in understanding how primary production is controlled by this small-scale turbulence.
• New parameterisations for internal vertical mixing, and the response of primary production, for use in coupled numerical models.
• Improved capability for estimating primary productivity in stratified waters by satellite remote sensing (ocean colour, sea surface temperature, wind mixing etc.)
• An overall development of our understanding of the dynamics of ecosystems that support important fisheries, and of our abilities in predicting ecological and biogeochemical responses to variations and changes in the climate of the marine environment.

Data Activity or Cruise Information

Cruise

Complete Cruise Metadata Report is available here

Fixed Station Information

Fixed Station Information

Physical-Biological Control of New Production within the Seasonal Thermocline: Fixed Station Bank2

This station is positioned in the centre of Jones Bank (see figure below), 100 km west of the Scilly Isles in the Celtic Sea on the north-west European shelf edge. It was first visited by the RRS Charles Darwin (CD173) in 2005.

All activities that have occurred here lie within a box bounded by co-ordinates 49.9075° N, 7.8989° W at the northwest corner and 49.8757° N, 7.8662° W at the southeast corner. The mean depth within the box is 106 m.

The deployment and sampling history, to date, for this station is summarised below:

Key

ADCP = Acoustic Doppler Current Profiler
CTD = Conductivity, temperature, depth sensor

Moorings

CTD Casts

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: Bank2

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.