Metadata Report for BODC Series Reference Number 247771


Metadata Summary

Data Description

Data Category CTD or STD cast
Instrument Type
NameCategories
Guildline Model 8770 Digital CTD  CTD; water temperature sensor
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 4/88CO154
BODC Series Reference 247771
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 1988-07-13 23:32
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval -
 

Spatial Co-ordinates

Latitude 55.26330 N ( 55° 15.8' N )
Longitude 1.49170 W ( 1° 29.5' W )
Positional Uncertainty Unspecified
Minimum Sensor Depth 1.3 m
Maximum Sensor Depth 28.8 m
Minimum Sensor Height 3.2 m
Maximum Sensor Height 30.7 m
Sea Floor Depth 32.0 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

Guildline 8770 CTD profiling system and 8709 probe

The Guildline 8770 is a portable ocean profiling system comprising a probe (model 8709), control unit and winch. Three versions of the probe are available: standard, Artic and batfish. The differences between the versions lie in numbers and types of connectors, and the existence of a protective cage (not present in the batfish version). The probe has a nominal drop rate of 1 ms -1 and a pressure rating of 1000 dbar.

The probe includes a resistance thermometer temperature sensor, a strain gauge pressure sensor, a conductivity cell, a temperature-compensated polarographic dissolved oxygen sensor and a combination pH sensor incorporating a glass measuring electrode and a calomel reference electrode. The probe digitises all measurements, and phase encodes and transmits the data to the control unit.

Specifications

Parameter Range Accuracy (180 days) Display Resolution Response time
Depth 0 to 1000 dbar

Linearity: ± 0.5%

Hysteresis: ± 0.25%

Zero offset: ± 1%

Sensitivity error: ± 1%

0.1 dbar < 1 msec
Temperature -3 to 38.99°C ± 0.02°C 0.01°C 60 msec
Conductivity ratio 0.001 to 1.6 ± 0.0004 0.0002 60 msec
Salinity (calculated) 0.1 to 40 ppt ± 0.04 ppt 0.01 ppt  
pH

6 to 9

2 to 12

± 0.05

± 0.1

0.01 30 sec to 90% for pH 6 or 10°C change
Dissolved Oxygen (calculated) 0 to 15 ppm ± 0.5 ppm (for 90 days) 0.01 ppm

5 sec to 90% for a change in oxygen only

3 min to 50% for a 10°C change in temperature

10 min to 90% for a 10°C change in temperature

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

RV Corystes 4/1988 CTD Data Documentation

Date July 1988
Area North East Coast
CTD Shallow water unit

Details of Lowerings

Altimeter fitted, Transmissometer fitted, logging at 1 per second (HP 1000).

(a) 4 anchor stations (25 hours) = 100
(b) 9 thorium stations = 9
(c) 10 on CTD section = 10
(Total = 119 profiles)

130 uncorrected, 91 corrected data files (not all vertical profiles; 11 from another source).

Temperature sensor changed during cruise:

S/N 46712 for stations 7 to 113
S/N 49504 for stations 146 to 218
S/N 46712 for stations 239 to 249

All temperature records were noisy - changing the sensor did not improve the data quality. An attempt was made to smooth the data with some success. Salinity calibrations satisfactory, except at anchor station 1. These data were not processed further because of this and there are only 3 anchor stations with corrected data.

Calibration Coefficients

Pressure

For all stations Pressure calibration of June 1988 used:

P(cor) = P(ctd) + dP

where dP = -1.5 db

Temperature

T(cor) = T(ctd) + dT

where dT = a*T(ctd)*T(ctd) + b*T(ctd) + C

For stations 88-113 and 239-249 (Calibration of August 1988):

a = 1.99212x10-4
b = -4.3376x10-3
c = 6.43x10-2

For stations 146-218 (Calibration of August 1988):

a = 1.42696x10-4
b = -7.07368x10-3
c = -1.53x10-2

Salinity

S(cor) = S(ctd) + dS

where:

Stations dS
88-113 (AS2) 0.10
53-80 0.09
146-174 (AS3) 0.22
178-186 0.21
192-218 (AS4) 0.23
239-248 0.08

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 COR4/88
Departure Date 1988-07-07
Arrival Date 1988-07-20
Principal Scientist(s)Steven M Rowlatt (Ministry of Agriculture, Fisheries and Food Burnham Laboratory)
Ship RV Corystes

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