Metadata Report for BODC Series Reference Number 442387


Metadata Summary

Data Description

Data Category Hydrography time series at depth
Instrument Type
NameCategories
Aanderaa thermistor chain  water temperature sensor; thermistor chains
Instrument Mounting subsurface mooring
Originating Country United Kingdom
Originator -
Originating Organization Proudman Oceanographic Laboratory (now National Oceanography Centre, Liverpool)
Processing Status banked
Project(s) Land Ocean Interaction Study (LOIS)
LOIS Shelf Edge Study (LOIS - SES)
 

Data Identifiers

Originator's Identifier at2412.775
BODC Series Reference 442387
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 1996-07-13 15:44
End Time (yyyy-mm-dd hh:mm) 1996-07-25 11:52
Nominal Cycle Interval 120.0 seconds
 

Spatial Co-ordinates

Latitude 56.45650 N ( 56° 27.4' N )
Longitude 8.96580 W ( 8° 57.9' W )
Positional Uncertainty 0.1 to 0.5 n.miles
Minimum Sensor Depth 6.32 m
Maximum Sensor Depth 82.32 m
Minimum Sensor Height 64.68 m
Maximum Sensor Height 140.68 m
Sea Floor Depth 147.0 m
Sensor Distribution Scattered at fixed depths - The sensors are scattered with respect to depth but each remains effectively at the same depth for the duration of the series
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
DEPHTC01 0 Metres ThermChainSensDepth Depth below surface of the water body by physical measurement and conversion from height above seabed using bathymetric depth
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)
TEMPTC01 2 Degrees Celsius WaterTemp_TC Temperature of the water body by in-situ thermistor
 

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

Aanderaa Thermistor Chain

Instrumentation

The thermistor string comprises 11 sensors electrically connected to a logger. The sensors are equally spaced along the string; string lengths range from 10m to 400m. Sensors used are Fenwal 2K iso-curve thermistors (type GB32JM19) with time constant of approximately 3.5min for 63pcent of step change. The thermistors have identical calibration curves to within ±0.1 °C.

Standard temperature ranges are: low range (-2.46 to 21.48 °C), high range (10.08 to 36.00 °C), wide range (-0.34 to 32.17 °C). A resistor, accurate to ±0.025deg C, within the logger is used to select the range.

Calibrations

The calibration formula, corresponding to the temperature range chosen, converts the logger reading N to degrees C with an accuracy of ±0.05deg C, The worst accumulated error (taking into account the accuracy of the formula, the thermistor and the resistor) is ±0.175 °C. These errors can be reduced by carrying out temperature calibrations at 0 °C. This can give an accuracy of ±0.05 °C. The theoretical limit of accuracy is ±0.0125 °C, approx. To approach this accuracy better interpolation formulae and frequent calibrations are required.

The data are logged either by Aanderaa TR loggers or by SeaData loggers (which incorporate a temperature sensor and hence record 12 channels).

Thermistor Depths

The sensor depths and corresponding data channels are as follows:

Parameter Depth
TEMPTC01 6.32m
TEMPTC02 13.92m
TEMPTC03 21.52m
TEMPTC04 28.12m
TEMPTC05 35.72m
TEMPTC06 43.32m
TEMPTC07 50.92m
TEMPTC08 58.52m
TEMPTC09 66.12m
TEMPTC10 73.72m
TEMPTC11 81.32m

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:

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:

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:

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

Land Ocean Interaction Study (LOIS)

Introduction

The Land Ocean Interaction Study (LOIS) was a Community Research Project of the Natural Environment Research Council (NERC). The broad aim of LOIS was to gain an understanding of, and an ability to predict, the nature of environmental change in the coastal zone around the UK through an integrated study from the river catchments through to the shelf break.

LOIS was a collaborative, multidisciplinary study undertaken by scientists from NERC research laboratories and Higher Education institutions. The LOIS project was managed from NERC's Plymouth Marine Laboratory.

The project ran for six years from April 1992 until April 1998 with a further modelling and synthesis phase beginning in April 1998 and ending in April 2000.

Project Structure

LOIS consisted of the following components:

Marine Fieldwork

Marine field data were collected between September 1993 and September 1997 as part of RACS(C) and SES. The RACS data were collected throughout this period from the estuaries and coastal waters of the UK North Sea coast from Great Yarmouth to the Tweed. The SES data were collected between March 1995 and September 1996 from the Hebridean slope. Both the RACS and SES data sets incorporate a broad spectrum of measurements collected using moored instruments and research vessel surveys.


LOIS Shelf Edge Study (LOIS - SES)

Introduction

SES was a component of the NERC Land Ocean Interaction Study (LOIS) Community Research Programme that made intensive measurements from the shelf break in the region known as the Hebridean Slope from March 1995 to September 1996.

Scientific Rationale

SES was devoted to the study of interactions between the shelf seas and the open ocean. The specific objectives of the project were:

Fieldwork

The SES fieldwork was focussed on a box enclosing two sections across the shelf break at 56.4-56.5 °N and 56.6-56.7 °N. Moored instrument arrays were maintained throughout the experiment at stations with water depths ranging from 140 m to 1500 m, although there were heavy losses due to the intensive fishing activity in the area. The moorings included meteorological buoys, current meters, transmissometers, fluorometers, nutrient analysers (but these never returned any usable data), thermistor chains, colour sensors and sediment traps.

The moorings were serviced by research cruises at approximately three-monthly intervals. In addition to the mooring work this cruises undertook intensive CTD, water bottle and benthic surveys with cruise durations of up to 6 weeks (3 legs of approximately 2 weeks each).

Moored instrument activities associated with SES comprised current measurements in the North Channel in 1993 and the Tiree Passage from 1995-1996. These provided boundary conditions for SES modelling activities.

Additional data were provided through cruises undertaken by the Defence Evaluation and Research Agency (DERA) in a co-operative programme known as SESAME.


Data Activity or Cruise Information

Data Activity

Start Date (yyyy-mm-dd) 1996-07-13
End Date (yyyy-mm-dd) 1996-07-25
Organization Undertaking ActivityProudman Oceanographic Laboratory (now National Oceanography Centre, Liverpool)
Country of OrganizationUnited Kingdom
Originator's Data Activity IdentifierPOLRIG#775
Platform Categorysubsurface mooring

Proudman Oceanographic Laboratory Moored Instrument Rig #775

This rig was deployed as part of the LOIS Shelf-Edge Study at site S140.

Rig position: 56° 27.40'N 08° 57.72'W
Deployed: 13 Jul 1996 15:44
from RRS Challenger (cruise CH128A)
Recovered: 25 Jul 1996 12:31
from RRS Challenger (cruise CH128A)

The instruments were anchored by 500kg of chain and kept erect by a 40" diameter buoy attached 1m below the sea surface.

Instruments deployed on the rig

Height above
Sea Bed
Instrument
143m S4 current meter (#1644)
142m MINLOG temperature probe (#2409)
141m to 65m 76m thermistor chain (#2412)
64m Aanderaa current meter (#11054)

Other Series linked to this Data Activity - 444437 477399 439029

Cruise

Cruise Name CH128A
Departure Date 1996-07-10
Arrival Date 1996-07-26
Principal Scientist(s)John H Simpson (University of Wales, Bangor School of Ocean Sciences)
Ship RRS Challenger

Complete Cruise Metadata Report is available here


Fixed Station Information

Fixed Station Information

Station NameLOIS(SES) S140
CategoryOffshore location
Latitude56° 27.14' N
Longitude8° 58.27' W
Water depth below MSL145.0 m

LOIS (SES) Mooring and CTD Site S140

Site S140 was a fixed station where moorings were deployed during the Land-Ocean Interaction Study (LOIS) Shelf Edge Study (SES). It was also one of fourteen CTD sites on repeat section S, across the Hebridean Slope, occupied by cruises between March 1995 and September 1996.

Instrument Deployment History

The following tables summarise the instruments deployed at this site for which data may be available.

1995

Mar Apr May Jun Jul Aug Sep Oct Nov Dec
CM a a       b b c c d
Met a a       b b b b b
BPR a a b b b c c d d e
ADCP     a a a b b c c d
TChn     a a a b c d d  
Tr     a a a b c d e e
Fl     a a a b c d e e
NA           a a      
WR             a a a  
OCS     a a a b        

1996

Jan Feb Mar Apr May Jun Jul Aug
CM d d e e f f f g
Met       c c c c  
BPR e e f f g g g h
ADCP d d e e f f f g
TChn         e e e f
Tr     f f g g g h
Fl     f f g g g h
NA         b b b  
OCS       c c c    

Each different letter in the tables above corresponds to an individual instrument record.

Glossary

Notes

  1. Transmissometers may have been fitted to some of the current meters.
  2. Only periods for which useful data were returned are shown.

Other Series linked to this Fixed Station for this cruise - 439029 444437 477210 477399

Other Cruises linked to this Fixed Station (with the number of series) - CD91B (3) CD93A (9) CH120 (4) CH121A (8) CH121C (8) CH123A (6) CH125A (6) CH126A (11)


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