Metadata Report for BODC Series Reference Number 750956
No Problem Report Found in the Database
Data Quality Report
|Series ref. number||Cycle||Flag||Comments|
|750956||920 - 936||M||Anomolous data spike|
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."
Lockheed Martin Sippican T-5 XBT Probe
The Expendable Bathythermograph system uses a sea water ground. As soon as an electrode within the nose of the expendable probe makes contact with the water, the circuit is complete and temperature or sound velocity data can be telemetered to the ship-board data processing equipment. The T-5 XBT Probe can be used within a maximum depth of 1830 m, with a rated ship speed of 6 knots and has a vertical resolution of 65 cm.
Manufacturer specifications can be found here
The data arrived at BODC in one ASCII format file representing the cast taken during JR20071129. This was reformatted to the internal QXF format using BODC established procedures. The following table shows how the variables within the ASCII files were mapped to appropriate BODC parameter codes:
|Originator's Variable||Units||Description||BODC Parameter Code||Units||Comments|
|Depth||m||Depth of instrument||DEPHCV01||m|
|Sound Velocity||ms-1||Velocity of sound through water column||SVELVP01||ms-1|
|Temperature||°C||Temperature of water||TEMPET01||°C|
The reformatted data were visualised using the in-house EDSERPLO software. Suspect data were marked by adding an appropriate quality control flag, missing data by both setting the data to an appropriate value and setting the quality control flag.
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:
- Irregularities such as unfeasible values
- Inconsistencies between related information, for example:
- Times for instrument deployment and for start/end of data series
- Length of record and the number of data cycles/cycle interval
- Parameters expected and the parameters actually present in the data cycles
- Originator's comments on meter/mooring performance and data quality
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:
- Spurious data at the start or end of the record.
- Obvious spikes occurring in periods free from meteorological disturbance.
- A sequence of constant values in consecutive data cycles.
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:
- Maximum and minimum values of parameters (spikes excluded).
- The occurrence of meteorological events.
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.
XBT Unit and Auxiliary Sensors
|Terminal Depth||1830 m|
|Depth Coeff. 1||0.0|
|Depth Coeff. 2||6.828|
|Depth Coeff. 3||-0.00182|
|Depth Coeff. 4||0.0|
|Pressure Pt Correction||100.0%|
No Project Information held for the Series
|Cruise Name||JR20071212 (JR196 Leg2)|
|Principal Scientist(s)||Miguel Angel Morales Maqueda (Proudman Oceanographic Laboratory)|
|Ship||RRS James Clark Ross|
Complete Cruise Metadata Report is available here
No Fixed Station Information held for the Series
|<||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.)|
|E||End of CTD Down/Up Cast|
|G||Non-taxonomic biological characteristic uncertainty|
|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|
|O||Improbable value - user quality control|
|0||no quality control|
|2||probably good value|
|3||probably bad value|
|6||value below detection|
|7||value in excess|
|A||value phenomenon uncertain|
|Q||value below limit of quantification|