Metadata Report for BODC Series Reference Number 1223397


Metadata Summary

Data Description

Data Category Hydrography time series at depth
Instrument Type
NameCategories
Sea-Bird SBE 37-SM MicroCAT C-T Sensor  water temperature sensor; salinity sensor
Instrument Mounting subsurface mooring
Originating Country United Kingdom
Originator Mr Povl Abrahamsen
Originating Organization British Antarctic Survey
Processing Status banked
Project(s) -
 

Data Identifiers

Originator's Identifier OP1_1113_6_SBE37_7386_2170M
BODC Series Reference 1223397
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2011-03-26 14:45
End Time (yyyy-mm-dd hh:mm) 2013-04-01 11:45
Nominal Cycle Interval 900.0 seconds
 

Spatial Co-ordinates

Latitude 60.62847 S ( 60° 37.7' S )
Longitude 42.08758 W ( 42° 5.3' W )
Positional Uncertainty 0.0 to 0.01 n.miles
Minimum Sensor Depth 2170.0 m
Maximum Sensor Depth 2170.0 m
Minimum Sensor Height 1482.0 m
Maximum Sensor Height 1482.0 m
Sea Floor Depth 3652.0 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 Approximate - Depth is only approximate
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
CNDCPR01 1 Siemens per metre InSituCond Electrical conductivity of the water body by in-situ conductivity cell
PREXMCAT 1 Decibars Pres_MCat Pressure (measured variable) exerted by the water body by semi-fixed moored SBE MicroCAT
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

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

Sea-Bird SBE 37-SM MicroCAT

The SBE 37-SM MicroCAT is a high accuracy conductivity and temperature recorder (pressure optional). Designed for moorings and other long-duration, fixed-site deployments, MicroCATs have non-corroding titanium housings rated for operation to 7000 metres or pressure sensor full scale-range. Communication with the MicroCAT is over an internal, 3-wire, RS-232C link. The MicroCAT's aged and pressure-protected thermistor has a long history of exceptional accuracy and stability (typical drift is less than 0.002° per year). Electrical isolation of the conductivity electronics eliminates any possibility of ground-loop noise.

Specifications

  Temperature
(°C)
Conductivity (S m -1 ) Optional Pressure
Measurement Range -5 to +35 0 to 7 (0 to 70 mS cm -1 ) 0 to full scale range: 20 / 100 / 350 / 1000 / 2000 / 3500 / 7000 metres
Initial accuracy 0.002 0.0003 0.1% of full scale range
Typical Stability 0.0002 per month 0.0003 per month 0.05% of full scale range per year
Resolution 0.0001 0.00001 0.002% of full scale range
Sensor Calibration +1 to +32 0 to 6; physical calibration over range 2.6 to 6 S m -1 , plus zero conductivity (air) Ambient pressure to full scale range in 5 steps
Memory 8 Mbyte non-volatile FLASH memory
Data Storage Converted temperature and conductivity: 6 bytes per sample (3 bytes each)
Time: 4 bytes per sample
Pressure (optional): 5 bytes per sample
Real-Time Clock 32,768 Hz TCXO accurate to ±1 minutes year -1
Standard Internal Batteries Nominal 10.6 Ampere-hour pack consisting of 12 AA lithium batteries. Provides sufficient capacity for more than 630,000 samples for a typical sampling scheme
Housing Titanium pressure case rated at 7000 metres
Weight (without pressure) In water: 2.3 kg
In air: 3.8 kg

Further information can be found via the following link: SBE 37-SM MicroCAT Datasheet

Data Processing Notes

Data submitted to BODC were transferred using standardised procedures and originator's parameters were matched to the BODC parameter vocabulary. Unit conversions were applied when originator's units did not match the ones specified on the dictionary.

Once data were transferred, several checks were performed on the file's header and data cycles. These include:

Data were inspected visually for anomalous values, spikes, jumps, effects of mooring "knock-down" and quality flags applied where appropriate. 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:

Originator's Data processing

Sampling strategy

Sampling was carried out as part of the BAS LTMS (British Antarctic Survey Long Term Monitoring and Survey). The project involved the deployment of moorings CI1, CI2, OP1, OP2, OP3, OP4, OP5 and OP6 in the Southern Ocean, situated north of Coronation Island and the Orkney Passage in the Weddell and Scotia Sea.

SBE 37 and SBE39 instruments were deployed on all mooring sites from 2005 onwards. Data have been collected at variable intervals: 5 minutes interval on CI moorings, 7.5 minute interval on the instruments deployed on OP2 in 2007 and 15 minute intervals since then. Gaps in the series may be caused by either instruments not being recovered, or data not being collected due to instrument malfunction.

Data processing

Little information is known with regards to the exact details of the calibrations carried out on the mooring data. Data processing, visualisation and calibration were carried out through the use of scripts for Matlab version R2014b produced and ran by the originator.

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

Data Activity

Start Date (yyyy-mm-dd) 2011-03-26
End Date (yyyy-mm-dd) 2013-04-01
Organization Undertaking ActivityBritish Antarctic Survey
Country of OrganizationUnited Kingdom
Originator's Data Activity IdentifierOP1
Platform Categorysubsurface mooring

Orkney Passage mooring 1 (OP1)

The mooring was deployed at the following positions:

Organisation Undertaking Activity British Antarctic Survey, Cambridge
Country of Organisation United Kingdom
Originator's Data Activity Identifier OP1
Platform Category Subsurface mooring
Latitude (+ve N) -60.6285
Longitude (+ve E) -42.0876
Water Depth (m) 3664

The mooring was deployed on the Orkney Passage on cruise JR20110319 (JR252) on 26 March 2011 and recovery was done on cruise JR20130317 (JR272B, JR273A, JR281, UKD-4) on 01 April 2013.

The table below lists the instruments deployed on this mooring:

Instrument type Serial Number Data start (UT) Data end (UT) Instrument depth (m)
Aquadopp 5993 2011-03-26 14:45:00 2013-04-01 11:45:00 1826
Sea Bird SBE39 4413 2011-03-26 14:45:00 2013-04-01 11:45:00 1826
Aquadopp 6180 2011-03-26 14:44:59 2013-04-01 11:44:59 2170
Sea Bird SBE37 7386 2011-03-26 14:45:01 2013-04-01 11:45:01 2170
Sea Bird SBE39 4713 2011-03-26 14:45:00 2013-04-01 11:45:00 2590
Aquadopp 6236 2011-03-26 14:44:59 2013-04-01 11:44:58 2944
Sea Bird SBE37 7385 2011-03-26 14:45:01 2013-04-01 11:45:01 2944
Aquadopp 6198 2011-03-26 14:45:00 2013-04-01 11:45:00 3607
Sea Bird SBE37 7387 2011-03-26 14:45:01 2013-04-01 11:45:01 3633

Other Series linked to this Data Activity - 1223361 1223404 1362742 1362766 1362754 1223373 1362730 1223385

Cruise

Cruise Name JR20110319 (JR252, JR254C)
Departure Date 2011-03-19
Arrival Date 2011-04-06
Principal Scientist(s)Povl Abrahamsen (British Antarctic Survey)
Ship RRS James Clark Ross

Complete Cruise Metadata Report is available here


Fixed Station Information

Fixed Station Information

Station NameOrkney Passage OP1
CategoryOffshore location
Latitude60° 39.16' S
Longitude42° 4.78' W
Water depth below MSL3700.0 m

Orkney Passage OP1 site

Site OP1 is part of the Orkney Passage mooring array which is an activity covered by the Long Term Monitoring and Survey British Antarctic Survey's (BAS) programme.The data collection is the result of an ongoing collaboration between BAS and the Lamont-Doherty Earth Observatory (LDEO).

This site was previously occupied in 2007 by an LDEO mooring (M4) and from 2011 onwards it became BAS's responsibility and was assigned its current name. The recovery/deployment history, including position details is presented below:

Deployed Recovered
Year Cruise Year Cruise Latitude (+ve N) Longitude (+ve E) Water Depth (m)
2011 JR20110319 (JR252, JR254C) 2013 JR20130317 (JR272B, JR273A, JR281, UKD-4) -60.6526 -42.0796 3700
2013 JR20130317 (JR272B, JR273A, JR281, UKD-4) 2015 JR20150309 (JR272D, JR310) -60.6285 -42.0876 3664
2015 JR20150309 (JR272D, JR310)     -60.625 -42.096 3644

Other Series linked to this Fixed Station for this cruise - 1223361 1223373 1223385 1223404 1362730 1362742 1362754 1362766


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