Metadata Report for BODC Series Reference Number 541810


Metadata Summary

Data Description

Data Category Currents -subsurface Eulerian
Instrument Type
NameCategories
Interocean S4 current meter  current meters
Instrument Mounting subsurface mooring
Originating Country United Kingdom
Originator -
Originating Organization Proudman Oceanographic Laboratory (now National Oceanography Centre, Liverpool)
Processing Status banked
Project(s) Provess
 

Data Identifiers

Originator's Identifier s41644.822
BODC Series Reference 541810
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 1999-03-30 13:45
End Time (yyyy-mm-dd hh:mm) 1999-04-26 19:55
Nominal Cycle Interval 600.0 seconds
 

Spatial Co-ordinates

Latitude 52.30200 N ( 52° 18.1' N )
Longitude 4.29450 E ( 4° 17.7' E )
Positional Uncertainty 0.1 to 0.5 n.miles
Minimum Sensor Depth 4.0 m
Maximum Sensor Depth 4.0 m
Minimum Sensor Height 15.0 m
Maximum Sensor Height 15.0 m
Sea Floor Depth 19.0 m
Sensor Distribution Sensor fixed, measurements made at fixed depths - The sensor is at a fixed depth, but measurements are made remotely from the sensor over a range of depths (e.g. ADCP measurements)
Sensor Depth Datum Sea floor reference - Depth measured as a height above sea floor but converted into a depth relative to the sea surface according to the same datum as used for sea floor depth (applicable to instrument depths not bathymetric depths)
Sea Floor Depth Datum Instantaneous - Depth measured below water line or instantaneous water body surface
 

Parameters

BODC CODE Rank Units Short Title Title
AADYAA01 1 Days Date(Loch_Day) Date (time from 00:00 01/01/1760 to 00:00 UT on day)
AAFDZZ01 1 Days Time(Day_Fract) Time (time between 00:00 UT and timestamp)
LCDAEL01 1 Degrees True CurrDir Current direction (Eulerian) in the water body by in-situ current meter and correction to true North
LCEWEL01 1 Centimetres per second CurrVelE_CM Eastward current velocity (Eulerian) in the water body by in-situ current meter
LCNSEL01 1 Centimetres per second CurrVelN_CM Northward current velocity (Eulerian) in the water body by in-situ current meter
LCSAEL01 1 Centimetres per second CurrSpd_CM Current speed (Eulerian) in the water body by in-situ current meter
 

Definition of Rank

  • Rank 1 is a one-dimensional parameter
  • Rank 2 is a two-dimensional parameter
  • Rank 0 is a one-dimensional parameter describing the second dimension of a two-dimensional parameter (e.g. bin depths for moored ADCP data)

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

InterOcean Spherical Solid State Sensor Current Meter S4 series

The S4 family are self-contained current measuring sensors enclosing all necessary solid state electronics for acquiring, processing and outputting data. Data retrieval is accomplished through a serial port without opening the instrument.

The spherical shape of the S4 is a contributing factor in the rejection of the vertical components of water movement and there are no protruding parts or sensor support structures to interfere with the water flow.

The S4 measures the magnitude and direction of the horizontal current motion of the water. Water flows through the electromagnetic field created by the instrument, thereby producing a voltage which is proportional to the magnitude of the water velocity past the sensor. This voltage is then sensed by two pairs of titanium electrodes located symmetrically on the equator of the spherical housing which forms the sensor.

Manufacturer's specifications: Meter (sphere, diameter 25cm) is designed for depths down to 1000m (S4 standard: glass-filled cycloaliphalic epoxy construction with grooved surface for hydrodynamic stability) or down to 6000m (S4D, deep: annealed borosilicate glass version with smooth surface). The meter is shackled directly into the mooring cable by means of an axial titanium load bearing shaft.

Meter comprises:-

  1. Electromagnetic, 2 axis current speed sensor, range 0 to 350cm/s (standard) 0 to 50 and 0 to 100cm/s (optional), resolution 0.2cm/s (standard) 0.03cm/s (0 to 50 range) 0.06cm/s (0 to 100 range), accuracy 2 per cent reading +/- 1cm/s. The sensor responds to the component of flow normal to its vertical axis.

  2. Flux-gate magnetometer compass for heading information used to reference the current direction to magnetic north, compass range 360°, resolution 0.5°, accuracy 2°, tilt +/- 25° for specified accuracy.

  3. Temperature stable quartz oscillator clock, accuracy 12 minutes/year.

  4. Optional automatic tilt compensation i.e. the allowable tilt of the meter from the vertical at which the vertical cosine response is fully corrected, angle range +/- 45°, resolution 0.6°, accuracy (speed correction) 1 per cent (angle output) 0.25°.

  5. Optional semiconductor (thermistor or platinum) temperature sensor, range -5 to +45 °C, resolution 0.05 °C, accuracy 0.2 °C, response time at 63 per cent 1 min (1.5 sec thermistor or 60msec platinum).

  6. Optional conductive conductivity sensor, range 5 to 70mS/cm, resolution 0.1mS/cm, accuracy 0.2mS/cm (optional inductive sensor, range 1 to 70mS/cm).

  7. Optional semiconductor strain gauge pressure sensor, range 0 to 1000dBar (70M option), resolution 1dBar (4mm with 70M option), accuracy 0.25 per cent fs.

  8. Recorder, CMOS static RAM microprocessor, 64KByte (128K or 256KByte optional) performs vector averaging, burst sampling and adaptive sampling.

Available versions of the S4 are listed in the table below:

S4RT Basic S4 current meter without memory installed, for real-time monitoring applications only.
S4 The basic S4 current measuring instrument, with current speed and direction sensors and internal memory from 64K to 1 megabyte of solid-state memory.
S4DW S4 current meter directional wave measuring instrument. Includes 1 megabyte of memory, 70 meter high-resolution depth, adaptive sampling, and Lithium battery pack, standard.
S4P S4 instrument outfitted for profiling applications. Fitted with fast response Platinum temperature sensor, inductive flow- through conductivity sensor, and high-resolution depth sensor as standard. Memory size may be from 64K to 1 megabyte.
S4D Deep water S4 instrument for use to depths of 6,000 meters.
S4A Advanced current measuring instrument with large memory capacity, and dual-mode logging capability. Memory size may be 32-256 megabytes. Includes high speed binary down-loads using Zmodem protocol with 32 bit CRC error checking. Adaptive current sampling is standard on this instrument.
S4ADW Large memory capacity S4 directional wave measuring instrument. Includes 32 to 256 megabyte memory, 70 meter high-resolution depth sensor, and Lithium battery pack, standard.
S4ADW-i New generation of S4ADW directional wave measuring instrument providing internally-processed directional wave data for direct output from the instrument without the need for external analysis software. Ideal multi-purpose oceanographic instrument for integrated-system applications requiring pre-processed output directly into a datalogger, PLC, modem, or other external device without need for PC computer. Used for directional wave, current, and tide measurements, with additional parameters available. Includes long-life lithium battery, and internal memory sizes from 32MB to 256MB.
S4AP An S4A instrument outfitted for profiling applications. Fitted with fast response Platinum temperature sensor, inductive flow-through conductivity sensor, and high- resolution depth sensor, standard. Memory size may be 32-256 megabytes.
S4AD Deep water S4A instrument for use to depths of 6,000 meters. Has all the same features and options as available with the standard S4A.
S4AH Same as S4A but uses 5 Hz sampling rate instead of 2 Hz. S4AHDW, S4AHP, S4AHD are 5 Hz models of the units listed above.

Further details are available from the manufacturer's specification sheet .

BODC Current Meter Screening

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

Header information is inspected for:

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

Data cycles are inspected using time 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 following types of irregularity, each relying on visual detection in the time series plot, are amongst those which may be flagged as suspect:

If a large percentage of the data is affected by irregularities, deemed abnormal, then instead of flagging the individual suspect values, a caution may be documented. Likewise documents will highlight irregularities seen in the current vector scatter plots such as incongruous centre holes, evidence of mooring 'knock-down', abnormal asymmetry in tidally dominated records or gaps as when a range of speeds or directions go unregistered due to meter malfunction.

The term 'knock-down' refers to the situation when the 'drag' exerted on a mooring at high current speeds may cause instruments to tilt beyond the angle at which they are intended to operate. At this point the efficiency of the current sensors to accurately record the flow is reduced.

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

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.

Data Processing Notes

The recorder of this S4 current meter was set to continuous mode with a vector averaging rate of 1200 half seconds.

Data processing was carried out at the Proudman Oceanographic Laboratory, Merseyside, UK. The time channel was adjusted to take into account the averaging period, by adding half the sampling interval to the recorded scan time.

The current data were corrected for a magnetic deviation of 2.2° W.


Project Information

PROcesses of Vertical Exchange in Shelf Seas (PROVESS)

Introduction

PROVESS was an interdisciplinary study of the vertical fluxes of properties through the water column and the surface and bottom boundary layers. The project was funded by the European Community MAST-III programme (MAS3-CT97- 0159) and ran from March 1998 to May 2001.

Scientific Rationale

PROVESS was based on the integration of experimental, theoretical and modelling studies with the aim of improving understanding and quantification of vertical exchange processes in the water column, in particular in the surface and benthic boundary layers and across the> pycnocline. PROVESS also explored mechanisms of physical-biological coupling in which vertical exchanges and turbulence significantly affect the environmental conditions experienced by the biota with particular reference to aggregation, flocculation, sedimentation and trophic interactions.

Fieldwork

The experimental phase of the project was carried out at two contrasting sites in the North Sea: the northern North Sea site (NNS) and the southern North Sea site (SNS).

The two sites had the following characteristics:

SNS NNS
Position 52° 15.0' N, 4° 17.0' E 59° 20.0' E, 1° 00.0' E
Time of year April-May September-November
Water depth (m) 16 100
M2 max amplitude (m s-1) 0.75 0.15
Max current (m s-1) 1.0 0.6
Delta T (deg C) mixed 7-1
Thermocline depth (m) mixed 35-100
Delta S 1 small
Halocline depth (m) 5-10 cf. thermocline depth
Max wind speed (m s-1) 20 25
Max wave height (m) 5 10
Max wave period (s) 8 10
Internal motion No Yes
Sediment muddy-sand muddy-sand
Biology eutrophic oligotrophic

At both locations measurements were concentrated at a central position with additional measurements being made to estimate horizontal gradients. Moored instruments (including current meters, temperature and pressure sensors, fluorometers, transmissometers, nutrient analysers and meteorological sensors) were deployed between 7 September and 5 November 1998 at the NNS and between 29 March and 25 May 1999 at the SNS. Each experiment was supported by intensive measurement series made from oceanographic ships and involving turbulence dissipation profiler CTD, particle size profilers, optical profilers, benthic sampling and water bottle sampling.

Details of the cruises were as follows:

Site Ship
(nationality)
Cruise
Mnemonic
Date
NNS Valdivia (GER) VA174 5 - 17 Sep 1998
  Dana (DK) D1198 14 - 26 Oct 1998
  Pelagia (NL) PE125 19 - 30 Oct 1998
  Challenger (UK) CH140 22 Oct - 9 Nov 1998
SNS Pelagia (NL) PE135 29 Mar - 9 Apr 1999
  Mitra (NL) MT0499 19 - 30 Apr 1999
  Belgica (BE) BG9912 17 - 21 May 1999

Data Activity or Cruise Information

Data Activity

Start Date (yyyy-mm-dd) 1999-03-30
End Date (yyyy-mm-dd) 1999-05-18
Organization Undertaking ActivityProudman Oceanographic Laboratory (now National Oceanography Centre, Liverpool)
Country of OrganizationUnited Kingdom
Originator's Data Activity IdentifierPOLRIG#822
Platform Categorysubsurface mooring

PROVESS Project POLRIG#822

This mooring was known within PROVESS as 'Rig D'. It was one of a cluster of moorings deployed at the main focus of the Southern North Sea Site during the spring of 1999.

Mooring type Single string mooring with toroid (J-rig).
Instrument S4 current meter (S/N 1644) 4 m below surface.

Cruise

Cruise Name PE136
Departure Date 1999-03-29
Arrival Date 1999-04-09
Principal Scientist(s)Hans van Haren (Royal Netherlands Institute for Sea Research)
Ship RV Pelagia

Complete Cruise Metadata Report is available here


Fixed Station Information

Fixed Station Information

Station NamePROVESS Southern North Sea Site
CategoryOffshore area
Latitude52° 18.00' N
Longitude4° 18.00' E
Water depth below MSL16.0 m

PROVESS Southern North Sea Site

Eleven mooring packages were deployed at PROVESS Southern North Sea site by Pelagia cruise PE136 in March 1999. One of these (Rig U) was lost, the NIOZ mooring was recovered by PE136 in April 1999 and the remaining nine were recovered by either RV Belgica cruise BG9912 (8 moorings) or RV Zirfea (Rig V) in May 1999.

The layout of the mooring array was:

BODC image

The asterisk represents an array of five moorings as detailed in the inset map.

Mooring data

The data returned from each rig were as follows:

Rig identifier Data
A POLRIG#820 Near-bed currents
Temperature, salinity and attenuance
B POLRIG#821 ADCP currents
Water level
Thermistor plus conductivity chain
D POLRIG#822 Currents
H POLRIG#824 Currents
Nutrients (nitrate + nitrite, silicate)
Chlorophyll
G POLRIG#823 Surface attenuance, nutrients (nitrate + nitrite) and chlorophyll
NIOZ   ADCP currents
Thermistor chain
Wave statistics (considered suspect)
V POLRIG#827 Currents
Temperature (4 depths)
Y POLRIG#829 Water level
Near-bed temperature
T POLRIG#825 ADCP currents
Water level
Thermistor plus conductivity chain
U Unknown None
X POLRIG#828 Water level
Near-bed temperature

CTD data

A total of 356 CTD casts were also collected during the three cruises surveying this area. These include:

Cruise identifier Cruise dates No. of CTD casts
RV Pelagia (#136) 29 March - 09 April 1999 133
Mitra (#0499) 19 April - 30 April 1999 170
RV Belgica (#9912) 17 May - 21 May 1999 53

Additonal data

Supporting meteorological data (including sea surface temperature and wave statistics) from two platforms (52° 33' N, 4° 3.5' E and 52° 16.4' N, 4° 17.8' E) were supplied to the project and are held by BODC. These series run from the beginning of March 1999 until the end of May 1999.

Other Series linked to this Fixed Station for this cruise - 529245 529257 529269 529270 529282 529294 529301 529313 529325 529337 529349 529350 541730 541742 541754 541766 541778 541791 541809 541822 541834 541846 541858 541871 541895 541902 541926 541938 553141 553294 553301 553313 564243


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