Metadata Report for BODC Series Reference Number 863661


Metadata Summary

Data Description

Data Category Hydrography time series at depth
Instrument Type
NameCategories
Sea-Bird SBE 37-SMP MicroCAT C-T Sensor  water temperature sensor; salinity sensor
Instrument Mounting subsurface mooring
Originating Country United Kingdom
Originator Dr Stuart Cunningham
Originating Organization National Oceanography Centre, Southampton
Processing Status banked
Project(s) Rapid Climate Change Programme
RAPIDMOC
 

Data Identifiers

Originator's Identifier 5EBH4/3900
BODC Series Reference 863661
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2007-11-10 18:00
End Time (yyyy-mm-dd hh:mm) 2008-11-16 16:00
Nominal Cycle Interval 1800.0 seconds
 

Spatial Co-ordinates

Latitude 27.85023 N ( 27° 51.0' N )
Longitude 13.53967 W ( 13° 32.4' W )
Positional Uncertainty 0.0 to 0.01 n.miles
Minimum Sensor Depth 438.0 m
Maximum Sensor Depth 438.0 m
Minimum Sensor Height 603.0 m
Maximum Sensor Height 603.0 m
Sea Floor Depth 1041.0 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 Approximate - Depth is only approximate
 

Parameters

BODC CODE Rank Units Title
AADYAA01 1 Days Date (time from 00:00 01/01/1760 to 00:00 UT on day)
AAFDZZ01 1 Days Time (time between 00:00 UT and timestamp)
ACYCAA01 1 Dimensionless Sequence number
CNDCPR01 1 Siemens per metre Electrical conductivity of the water body by in-situ conductivity cell
PREXMCAT 1 Decibars Pressure (measured variable) exerted by the water body by semi-fixed moored SBE MicroCAT
PSALPR01 1 Dimensionless Practical salinity of the water body by conductivity cell and computation using UNESCO 1983 algorithm
TEMPPR01 1 Degrees Celsius 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-SMP MicroCAT

The SBE 37-SMP MicroCAT is a high accuracy conductivity and temperature recorder (pressure optional) with Serial interface, internal battery, non-volatile FLASH Memory and integral Pump. The Integral Pump runs for 1 second each time the MicroCAT samples, improving the conductivity response and giving improved anti-foul protection.

Designed for moorings and other long-duration, fixed-site deployments, MicroCATs have non-corroding titanium housings rated for operation to 7000 meters 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°C per year). Electrical isolation of the conductivity electronics eliminates any possibility of ground-loop noise.

Specifications

  Temperature
(°C)
Conductivity (S/m) Optional Pressure
Measurement Range -5 to +35 0 to 7 (0 to 70 mS/cm) 0 to full scale range: 20 / 100 / 350 / 600 / 1000 / 2000 / 3500 / 7000 metres
Initial accuracy 0.002 0.0003 0.1% of full scale range
Typical Stability 0.0002 0.0003 0.05% of full scale range
Resolution 0.0001 0.00001 0.002% of full scale range
Data Storage Temperature and conductivity: 6 bytes per sample
Time: 4 bytes per sample
Pressure (optional): 5 bytes per sample
Clock stability 5 seconds per month
Standard Internal Batteries Nominal 10.6 Ampere-hour pack consisting of twelve AA lithium batteries. Provides sufficient capacity for more than 100,000 samples for a typical sampling scheme
Housing Titanium pressure case rated at 7000 metres
Weight (without pressure) In water: 3kg
In air: 5kg

Further information can be found via the following link: Sea-Bird SBE 37-SMP MicroCAT Datasheet

RAPIDMOC Calibration Coefficients: Series 863661

BODC Series identifier 863661
Instrument Serial number 3900
Deployment Cruise RRS Discovery cruise D324
Recovery Cruise RRS Discovery cruise D334

Processing Log

Variable Pre-cruise Post-cruise
Conductivity [mS/cm] NaN 0.0306
Temperature [oC] -0.0019 -0.0027
Pressure [dbar] -2.0000 1.7000

Pre and post cruise coefficients were averaged and applied as constant offsets to the temperature and pressure channels.
Post cruise coefficients were applied as a constant offset to the conductivity channel
Pressure drift removal? n
Conductivity pressure correction redone? n
Skipped conductivity intervals: [0]
Skipped temperature intervals : [0]
Skipped pressure intervals : [0]
Number of additional C points skipped interactively: [0]
Number of additional C points skipped automatically: [0]

RAPIDMOC/MOCHA Sea-Bird MicroCAT data processing document

This document outlines the procedures undertaken to process and quality assure the MicroCAT data collected under the RAPIDMOC and MOCHA projects.

Originator's processing

The raw data are downloaded from the instrument and converted to ASCII format. All processing is performed in Matlab.

Calculating calibration coefficients

Prior to deployment and on recovery, a CTD dip is performed with the MicroCATs strapped onto the CTD frame. This allows calibration of the MicroCAT data by comparing the MicroCAT data with the CTD data. As the MicroCATs adjustment is much slower than the CTD, data are only compared during bottle stops and after the sensors have adjusted. Bottle stops on these calibration dips last no less than 5 minutes.

Any discrepancy between the MicroCAT clock and the CTD clock is calculated and corrected if necessary.

An average offset (MicroCAT - CTD) is calculated for temperature, conductivity and pressure during the stable period of each bottle stop and interpolated onto the instrument deployment depths. For temperature and conductivity, an average of the offsets derived during the bottle stops is calculated for a specified pressure range where the data are stable (deep water). For pressure, the average offset interpolated to the deployment depth is used. If the calibration dip is shallower than the deployment depth, the offset is extrapolated to the deployment depth.

All the offsets are visually checked and adjusted if necessary.

Applying calibrations

The data are calibrated using the pre and post deployment calibration coefficients. The calibration can be applied as either

If required, a conductivity pressure correction can be applied. This is used if the pressure channel shows spurious data in a particular time interval. A drift in the pressure data can also be removed.

To aid the quality of the calibration, data from CTD casts performed near mooring locations on previous cruises are used as a reference and are visually compared with the MicroCAT data.

Quality control

All variables in specified time intervals can be set to dummy values if the data are suspect and it is also possible to apply an offset to a subsection of a particular channel, if required. Interactive despiking can be carried out on the temperature and conductivity data, if present, by selecting data based on a T-S plot. Automatic despiking can also be performed using the option to exclude data outside the 6σ area.

The last stage of the processing is to grid the data onto a pressure field and visually check against historical data. This enables the calibrations to be checked and adjusted if necessary. On occasion, comparison of the time series with historical data and series from nearby instruments highlights the need for removal of a drift from one or more data channels. This is accomplished by removing a linear trend from the appropriate channel(s) and may affect the entire series or a subsection thereof. If a trend has been removed it will be noted in the 'RAPIDMOC Calibration Coefficients' section of the documentation.

BODC processing

Data are received after quality checks have been made and calibrations have been applied. The data files are submitted in ASCII format as one file per instrument.

Once the submitted data files are safely archived, the data undergo reformatting and banking procedures:

Parameter mapping

The following describes the parameters contained in the originator's files and their mapping to BODC parameter codes:

Identifier Unit Definition BODC parameter code Units Unit conversion Comments
YY year Year AADYAA01 days - Combined with MM and DD to form a date and transferred
MM month Month AADYAA01 days - Combined with MM and DD to form a date and transferred
DD day Day AADYAA01 days - Combined with MM and DD to form a date and transferred
HH hour Decimal hours AAFDZZ01 days /24 Transferred
P decibar Pressure PREXMCAT decibars - Transferred
T °C Temperature (IPTS-90) TEMPPR01 °C - Transferred
C mS/cm Conductivity CNDCPR01 S/m /10 Transferred

Parameter derivation

The following describes the parameters derived by BODC and their mapping to BODC parameter codes:

BODC parameter code Units Variables Definition Units Equation Comments
PSALPR01 dimensionless PREXMCAT
TEMPPR01
CNDCPR01
Pressure
Temperature
Conductivity
decibars
°C
S/m
UNESCO 1983 polynomial for salinity -

Project Information

Rapid Climate Change (RAPID) Programme

Rapid Climate Change (RAPID) is a £20 million, six-year (2001-2007) programme of the Natural Environment Research Council (NERC). The programme aims to improve our ability to quantify the probability and magnitude of future rapid change in climate, with a main (but not exclusive) focus on the role of the Atlantic Ocean's Thermohaline Circulation.

Scientific Objectives

Projects

Overall 38 projects have been funded by the RAPID programme. These include 4 which focus on Monitoring the Meridional Overturning Circulation (MOC), and 5 international projects jointly funded by the Netherlands Organisation for Scientific Research, the Research Council of Norway and NERC.

The RAPID effort to design a system to continuously monitor the strength and structure of the North Atlantic Meridional Overturning Circulation is being matched by comparative funding from the US National Science Foundation (NSF) for collaborative projects reviewed jointly with the NERC proposals. Three projects were funded by NSF.

A proportion of RAPID funding as been made available for Small and Medium Sized Enterprises (SMEs) as part of NERC's Small Business Research Initiative (SBRI). The SBRI aims to stimulate innovation in the economy by encouraging more high-tech small firms to start up or to develop new research capacities. As a result 4 projects have been funded.


Monitoring the Meridional Overturning Circulation at 26.5N (RAPIDMOC)

Scientific Rationale

There is a northward transport of heat throughout the Atlantic, reaching a maximum of 1.3PW (25% of the global heat flux) around 24.5°N. The heat transport is a balance of the northward flux of a warm Gulf Stream, and a southward flux of cooler thermocline and cold North Atlantic Deep Water that is known as the meridional overturning circulation (MOC). As a consequence of the MOC northwest Europe enjoys a mild climate for its latitude: however abrupt rearrangement of the Atlantic Circulation has been shown in climate models and in palaeoclimate records to be responsible for a cooling of European climate of between 5-10°C. A principal objective of the RAPID programme is the development of a pre-operational prototype system that will continuously observe the strength and structure of the MOC. An initiative has been formed to fulfill this objective and consists of three interlinked projects:

The entire monitoring array system created by the three projects will be recovered and redeployed annually until 2008 under RAPID funding. From 2008 until 2014 the array will continue to be serviced annually under RAPID-WATCH funding.

The array will be focussed on three regions, the Eastern Boundary (EB), the Mid Atlantic Ridge (MAR) and the Western Boundary (WB). The geographical extent of these regions are as follows:

References

Baehr, J., Hirschi, J., Beismann, J.O. and Marotzke, J. (2004) Monitoring the meridional overturning circulation in the North Atlantic: A model-based array design study. Journal of Marine Research, Volume 62, No 3, pp 283-312.

Baringer, M.O'N. and Larsen, J.C. (2001) Sixteen years of Florida Current transport at 27N Geophysical Research Letters, Volume 28, No 16, pp3179-3182

Bryden, H.L., Johns, W.E. and Saunders, P.M. (2005) Deep Western Boundary Current East of Abaco: Mean structure and transport. Journal of Marine Research, Volume 63, No 1, pp 35-57.

Hirschi, J., Baehr, J., Marotzke J., Stark J., Cunningham S.A. and Beismann J.O. (2003) A monitoring design for the Atlantic meridional overturning circulation. Geophysical Research Letters, Volume 30, No 7, article number 1413 (DOI 10.1029/2002GL016776)


Data Activity or Cruise Information

Data Activity

Start Date (yyyy-mm-dd) 2007-11-07
End Date (yyyy-mm-dd) 2008-11-19
Organization Undertaking ActivityNational Oceanography Centre, Southampton
Country of OrganizationUnited Kingdom
Originator's Data Activity IdentifierEBH4#5
Platform Categorysubsurface mooring

RAPID Moored Instrument Rig EBH4#5

This rig was deployed as part of the Eastern Boundary (EB) array of the RAPIDMOC project.

Deployment Cruise RRS Discovery cruise D324
Recovery Cruise RRS Discovery cruise D334

This rig was anchored by a 600 kg anchor and was kept erect by groups of sub-surface floats attached along the mooring.

Instruments deployed on the rig

Depth Instrument
362 m Sea-Bird SBE37 SMP MicroCAT (#3892)
438 m Sea-Bird SBE37 SMP MicroCAT (#3900)
539 m Sea-Bird SBE37 SMP MicroCAT (#3901)
642 m Sea-Bird SBE37 SMP MicroCAT (#3903)
745 m Sea-Bird SBE37 SMP MicroCAT (#3904)
844 m Sea-Bird SBE37 SMP MicroCAT (#3912)

Other Series linked to this Data Activity - 863673 863685 863648 863697 863704

Cruise

Cruise Name D324
Departure Date 2007-10-06
Arrival Date 2007-11-09
Principal Scientist(s)Stuart A Cunningham (National Oceanography Centre, Southampton)
Ship RRS Discovery

Complete Cruise Metadata Report is available here


Fixed Station Information

Fixed Station Information

Station NameEastern Boundary Array
CategoryOffshore area
Latitude25° 51.60' N
Longitude18° 43.98' W
Water depth below MSL

RAPIDMOC Eastern Boundary (EB) Array

The Eastern Boundary Array defines a box in which moorings are deployed at the eastern side of the North Atlantic as part of the RAPIDMOC project. The box region has latitudinal limits of 23.5° N to 29° N and longitudinal limits of 12° W to 25.5° W. Moorings have occupied this region since 2004 and are typically deployed for 6 to 18 months.

Moored data summary

A description of the data types can be found at the bottom of this document.

Year Cruise ID Number of moorings Data types (number of instruments)
2004 D277, PO319 11 BPR (7), CM (10), MCTD (32)
2005 CD170,CD177 15 ADCP (1), BPR (4), CM (4), MCTD (71), IES (2), MMP (1)
2006 D304, PO343, PO345 24 BPR (6), CM (4), MCTD (78), MMP (1)
2007 D324 13 BPR (3), MCTD (53), IES (2)
2008 D334 14 BPR (3), CM (2), MCTD (44), IES (1)
2009 D344 14 BPR (4), CM (2), MCTD (44)
2011 D359, JC064 22 BPR (12), CM (18), MCTD (80), IES (1)
2012 D382 9 BPR (6), CM (10), MCTD (50)

Cruise data summary

During the cruises to service the moored array, a variety of data types are collected. The table below is a summary of these data. The number of CTD profiles performed on these cruises within the box region defined above is also included. Trans-Atlantic hydrographic CTD sections have also been performed since 2004 and are included in the table.

Cruise ID Cruise description Data types Number of CTD profiles performed within the box region
D277 Initial array deployment MET, NAV, SADCP, SURF -
D279 Hydrographic section CTD, DIS, LADCP, MET, NAV, SADCP, SURF 21
CD170 Array service BATH, CTD, DIS, MET, NAV, SADCP, SURF 4
CD177 Array service BATH, CTD, DIS, MET, NAV, SADCP, SURF 6
D304 Array service CTD, DIS, MET, NAV, SADCP, SURF 8
PO343 Array service CTD, DIS, MET, NAV, SADCP, SURF 5
PO345 Array service CTD, DIS, MET, NAV, SADCP, SURF 4
D324 Array service CTD, DIS, MET, NAV, SADCP, SURF 5
D334 Array service CTD, DIS, MET, NAV, SADCP, SURF 15
D344 Array service CTD, DIS, MET, NAV, SADCP, SURF 5
D346 Hydrographic section CTD, DIS, LADCP, MET, NAV, SADCP, SURF 22
D359 Array service CTD, DIS, MET, NAV, SADCP, SURF 4
JC064 Array service CTD, DIS, MET, NAV, SADCP, SURF 5
D382 Array service CTD, DIS, MET, NAV, SADCP, SURF 5

Data type ID and description

Data type ID Description
ADCP Acoustic Doppler Current Profiler
BATH Bathymetry
BPR Bottom Pressure Recorder
CM Current Meter
CTD Conductivity-Temperature-Depth profiler
DIS Discrete water bottle samples
IES Inverted Echo Sounder
LADCP Lowered Acoustic Doppler Current Profiler
MET Meteorology
MCTD Moored Conductivity-Temperature-Depth sensor
MMP McLane Moored Profiler - profiling CTD and current meter
NAV Navigation
SADCP Shipborne Acoustic Doppler Current Profiler
SURF Sea surface data

Other Series linked to this Fixed Station for this cruise - 768756 768768 768781 768836 768848 863206 863218 863231 863243 863255 863267 863279 863280 863292 863311 863323 863335 863347 863359 863360 863372 863384 863396 863403 863415 863427 863439 863440 863452 863464 863476 863488 863507 863519 863520 863532 863544 863556 863568 863581 863593 863600 863612 863624 863636 863648 863673 863685 863697 863704 863716 863728 863741 863753 863765 864117 864129 946161 946173 946197

Other Cruises linked to this Fixed Station (with the number of series) - CD170 (52) CD177 (31) D277 (39) D304 (57) D324 (60) D334 (44) D344 (48) D346 (22) D359 (44) D382 (5) JC064 (46) PO343 (10) PO345 (30)


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