Metadata Report for BODC Series Reference Number 962609


Metadata Summary

Data Description

Data Category Currents -subsurface Eulerian
Instrument Type
NameCategories
Aanderaa Seaguard Recording Current Meter  current meters
Instrument Mounting subsurface mooring
Originating Country France
Originator Dr Valerie Quiniou-Ramus
Originating Organization Total S.A.
Processing Status QC in progress
Project(s) SIMORC
 

Data Identifiers

Originator's Identifier CANYON_SG_CURR&TEMP&SAL
BODC Series Reference 962609
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2009-01-16 15:10
End Time (yyyy-mm-dd hh:mm) 2009-07-26 06:40
Nominal Cycle Interval 600.0 seconds
 

Spatial Co-ordinates

Latitude 7.40010 S ( 7° 24.0' S )
Longitude 11.25930 E ( 11° 15.6' E )
Positional Uncertainty 0.01 to 0.05 n.miles
Minimum Sensor Depth 1784.0 m
Maximum Sensor Depth 1784.0 m
Minimum Sensor Height 4.0 m
Maximum Sensor Height 4.0 m
Sea Floor Depth 1788.0 m
Sensor Distribution Fixed common depth - All sensors are grouped effectively at the same depth which is effectively fixed 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
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)
ACYCAA01 1 Dimensionless Record_No Sequence number
LCDAEL01 1 Degrees True CurrDir Current direction (Eulerian) in the water body by in-situ current meter and correction to true North
LCSAEL01 1 Centimetres per second CurrSpd_CM Current speed (Eulerian) in the water body by in-situ current meter
PSALPR01 1 Dimensionless P_sal Practical salinity of the water body by conductivity cell and computation using UNESCO 1983 algorithm
TEMPPR01 1 Degrees Celsius Temp Temperature of the water body
 

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

SIMORC data access conditions

The data collated and held at BODC on behalf of the SIMORC project are restricted. However, the data will be available to download from the Official SIMORC Website, as part of the project protocol. The data set will initially include data from the oil companies TOTAL, Shell and BP.


Narrative Documents

Aanderaa SEAGUARD Recording Current Meter

A multi-frequency Doppler current sensor for measuring horizontal current speed and direction. The shallow water (SW), intermediate water (IW) and deep water (DW) models can be deployed to 300 m, 2000 m and 6000 m, respectively. The instrument has a maximum sampling rate of 0.5 Hz, a velocity range of 0 - 300 cm/s, and incorporates an electronic compass and a tilt sensor. A number of additional oceanographic sensors may also be attached.

Further details can be found in 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.

BODC Processing

Data were received by BODC in ASCII format files (Fugro format). They were reformatted to QXF format using BODC transfer function 400. The following table shows how the variables within the files were mapped to the appropriate BODC parameter codes:

Original parameter name Original Units Description BODC Parameter Code BODC Units Comments
Time DD-MON-YY hh:mm:ss Date and time (GMT) AADYAA01 + AAFDZZ01 Day number and day fraction (GMT)  
Curr_Speed m/s Speed LCSAEL01 cm/sec *100
Curr_Direction degrees True Direction LCDAEL01 degrees True  
Temp degrees Celsius Sea temperature TEMPPR01 degrees Celsius  
Salinity PSU Salinity PSALPR01 PSU  

Following transfer to QXF, the data were screened using BODC's in-house visualisation software, EDSERPLO.


Project Information

System of Industry Metocean data for the Offshore and Research Communities (SIMORC)

The EU-funded SIMORC project is a collaborative effort between MARIS (Netherlands), BODC (UK), the International Association of Oil and Gas Producers (OGP) and IOC-IODE to provide a harmonised and quality controlled metocean data set from data collected by oil and gas producers, accessible through the SIMORC protocol.


Data Activity or Cruise Information

Data Activity

Start Date (yyyy-mm-dd) 2009-01-16
End Date (yyyy-mm-dd) 2009-07-26
Organization Undertaking ActivityTotal S.A.
Country of OrganizationFrance
Originator's Data Activity IdentifierCanyon
Platform Categorysubsurface mooring

SIMORC Total Canyon Current Meter and ADCP mooring.

The survey at this site was made up of a single mooring.

This mooring was deployed in a water depth of 1795 metres. (Nominal position of 7.40007°S 11.259305°E):

Meter No. Instrument Depth (m) Instrument Type Total Time Period Comments
7020 1787.5 RDI 75 Hz ADCP 17-JAN-2009 TO 25-JUL-2009 Upward-looking.
104 1791.3 Aanderaa Seaguard RCM 17-JAN-2009 TO 25-JUL-2009  

Other Series linked to this Data Activity - 1052443 962437

Cruise

Cruise Name Seabulk Luanda 2009
Departure Date 2009-01-14
Arrival Date 2009-01-19
Principal Scientist(s)
Ship Seabulk Luanda

Complete Cruise Metadata Report is available here


Fixed Station Information

Fixed Station Information

Station NameCanyon, Angola Block 32
CategoryOffshore location
Latitude7° 24.00' S
Longitude11° 15.56' E
Water depth below MSL1795.0 m

Total - Angola Block 32 - Canyon

Latitude Longitude Water depth (m)
7.400007°S 11.259305°E 1795

This fixed station is in Block 32, offshore Angola. A mooring was deployed at this site in January 2009 to cover a 12-month period of measurements of currents through the water column. Prior to the mooring deployment, a CTD dip was undertaken to check the actual water depth.

Other Series linked to this Fixed Station for this cruise - 962437 963404 963416

Other Cruises linked to this Fixed Station (with the number of series) - Petrogas1 (1)


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