Metadata Report for BODC Series Reference Number 325414


Metadata Summary

Data Description

Data Category CTD or STD cast
Instrument Type CTD/STD cast
Instrument Mounting research vessel
Originating Country United Kingdom
Originator -
Originating Organization Ministry of Agriculture, Fisheries and Food Lowestoft Fisheries Laboratory (now Centre for Environment, Fisheries and Aquaculture Science Lowestoft Laboratory)
Processing Status banked
Project(s) -
 

Data Identifiers

Originator's Identifier AR7/90/1
BODC Series Reference 325414
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 1990-07-11 04:20
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval -
 

Spatial Co-ordinates

Latitude 65.14930 N ( 65° 9.0' N )
Longitude 30.84570 W ( 30° 50.7' W )
Positional Uncertainty Unspecified
Minimum Sensor Depth 3.5 m
Maximum Sensor Depth 1519.8 m
Minimum Sensor Height 13.2 m
Maximum Sensor Height 1529.5 m
Sea Floor Depth 1533.0 m
Sensor Distribution Variable common depth - All sensors are grouped effectively at the same depth, but this depth varies significantly during the series
Sensor Depth Datum Instantaneous - Depth measured below water line or instantaneous water body surface
Sea Floor Depth Datum Instantaneous - Depth measured below water line or instantaneous water body surface
 

Parameters

BODC CODE Rank Units Short Title Title
PRESPR01 1 Decibars Pres_Z Pressure (spatial co-ordinate) exerted by the water body by profiling pressure sensor and corrected to read zero at sea level
PSALPR01 1 Dimensionless P_sal Practical salinity of the water body by conductivity cell and computation using UNESCO 1983 algorithm
TEMPST01 1 Degrees Celsius WC_temp_CTD Temperature of the water body by CTD or STD
 

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

Centre for Environment, Fisheries and Aquaculture Science (Cefas) data access conditions

The Centre for Environment, Fisheries and Aquaculture Science (Cefas) is an Executive Agency of the Department of Environment, Food and Rural Affairs (Defra), formerly the Ministry of Agriculture, Fisheries and Food (MAFF). It was also known previously as the Directorate of Fisheries Research (DFR). This data policy refers to data collected by the organisation under all titles.


Narrative Documents

RV Aranda Cruise 7/1990 CTD Data Documentation

Calibrations

CTD profiles were corrected using calibration coefficients derived from cruise Aranda 7/1990. A summary of the results is presented herein.

Temperature

CTD temperature was corrected by applying the coefficients derived from the laboratory calibration of 21 June 1990:

T(cor) = T(ctd) + dT

where:

dT = c + b*T(ctd) + a*T(ctd)*T(ctd)
a = -0.32614x10 -4
b = -0.613104x10 -3
c = 0.925468x10 -3

Pressure

CTD pressure was corrected by applying the coefficients derived from the laboratory calibration of 21 June 1990:

P(cor) = P(ctd) + dP

where:

dP = a*T(cor) + b*P(ctd) + c
a = 0.10425532
b = 0.36670552x10 -2
c = 0.541245580

Conductivity Ratio

CTD conductivity was corrected by converting water sample salinity to in situ conductivity (from the UNESCO algorithm) and comparing it to CTD conductivity values. The water sample salinity was measured using Guildline bench salinometer. A least squares regression was performed on the corrected data to derive the calibration coefficients a, b and c and the corrected conductivity ratio is:

CR(cor) = CR(ctd) x CR

where:

CR = a*T(cor) + b*P(cor) + c
a = 0.102667575x10 -3
b = -0.238495919x10 -7
c = 0.993272182

The derived P, T and CR calibration coefficients were used to correct the CTD profiles of the cruise.

Data Quality

Station details are shown in the table below. The root mean square (rms) difference between the corrected CTD salinity and water sample salinity was 0.004 for 6 observations. This was found to be acceptable, in view of the errors inherent in the CTD and bench salinometer. Only stations 1 and 2 were used in determining the calibration coefficients.

Station Latitude Longitude Date Time Depth
1 65° 08.96' N 30°50.74' W 11 July 04.20 1533m
2 64° 46.04' N 30°33.16' W 11 July 14.57 2192m
3 64° 17.35' N 33°42.39' W 13 July 14.33 1966m

In correcting the CTD profiles at stations 1, 2 and 3, odd values of CR were deleted from the top 100 m.

The profile of station 3 was very noisy in the first 400 m and, consequently, these were deleted.

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


No Project Information held for the Series

Data Activity or Cruise Information

Cruise

Cruise Name AR1/90
Departure Date 1990-07-09
Arrival Date 1990-07-18
Principal Scientist(s)Edward M Gmitrowicz (Ministry of Agriculture, Fisheries and Food Lowestoft Fisheries Laboratory)
Ship Aranda

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

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