Metadata Report for BODC Series Reference Number 1134702


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) RAPIDMOC
RAPID-WATCH
 

Data Identifiers

Originator's Identifier MAR2_8/5778
BODC Series Reference 1134702
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2011-09-25 21:00
End Time (yyyy-mm-dd hh:mm) 2012-11-07 17:30
Nominal Cycle Interval 1800.0 seconds
 

Spatial Co-ordinates

Latitude 24.17750 N ( 24° 10.6' N )
Longitude 49.76300 W ( 49° 45.8' W )
Positional Uncertainty Unspecified
Minimum Sensor Depth 4274.0 m
Maximum Sensor Depth 4274.0 m
Minimum Sensor Height 942.0 m
Maximum Sensor Height 942.0 m
Sea Floor Depth 5216.0 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 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
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

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 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
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

Instrument serial number 5778
Mooring identifier: MAR2#8

Processing log

Variable Pre-cruise Post-cruise
Conductivity [mS/cm] NaN 0.0015
Temperature [°C] 0.0028 0.0009
Pressure [dbar] 12.2000 12.1000

General conductivity trend applied? n
Average temperature applied? y
Average pressure applied? y
Pressure drift removal? y
Equation of pressure drift fit: yfit = a1*(1-exp(-a2*(x-x(1)))) + a3*(x-x(1)) + a4
Coefficients of pressure drift fit: a1 = 3.961754, a2 = 0.071523, a3 = -0.000367, a4 = 4341.206121
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: [8]

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

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)


RAPID- Will the Atlantic Thermohaline Circulation Halt? (RAPID-WATCH)

RAPID-WATCH (2007-2014) is a continuation programme of the Natural Environment Research Council's (NERC) Rapid Climate Change (RAPID) programme. It aims to deliver a robust and scientifically credible assessment of the risk to the climate of UK and Europe arising from a rapid change in the Atlantic Meridional Overturning Circulation (MOC). The programme will also assess the need for a long-term observing system that could detect major MOC changes, narrow uncertainty in projections of future change, and possibly be the start of an 'early warning' prediction system.

The effort to design a system to continuously monitor the strength and structure of the North Atlantic MOC is being matched by comparative funding from the US National Science Foundation (NSF) for the existing collaborations started during RAPID for the observational arrays.

Scientific Objectives

This work will be carried out in collaboration with the Hadley Centre in the UK and through international partnerships.

Mooring Arrays

The RAPID-WATCH arrays are the existing 26°N MOC observing system array (RAPIDMOC) and the WAVE array that monitors the Deep Western Boundary Current. The data from these arrays will work towards meeting the first scientific objective.

The RAPIDMOC array consists of moorings focused in three geographical regions (sub-arrays) along 26.5° N: Eastern Boundary, Mid-Atlantic Ridge and Western Boundary. The Western Boundary sub-array has moorings managed by both the UK and US scientists. The other sub-arrays are solely led by the UK scientists. The lead PI is Dr Stuart Cunningham of the National Oceanography Centre, Southampton, UK.

The WAVE array consists of one line of moorings off Halifax, Nova Scotia. The line will be serviced in partnership with the Bedford Institute of Oceanography (BIO), Halifax, Canada. The lead PI is Dr Chris Hughes of the Proudman Oceanographic Laboratory, Liverpool, UK.

All arrays will be serviced (recovered and redeployed) either on an annual or biennial basis using Research Vessels from the UK, US and Canada.

Modelling Projects

The second scientific objective will be addressed through numerical modelling studies designed to answer four questions:


Data Activity or Cruise Information

Data Activity

Start Date (yyyy-mm-dd) 2011-09-25
End Date (yyyy-mm-dd) 2012-11-07
Organization Undertaking ActivityNational Oceanography Centre, Southampton
Country of OrganizationUnited Kingdom
Originator's Data Activity IdentifierMAR2#8
Platform Categorysubsurface mooring

RAPID Moored Instrument Rig MAR2#8

This rig was deployed as part of the Mid-Atlantic Ridge (MAR) array of the RAPIDMOC project.

Deployment cruise RRS James Cook cruise JC064
Recovery cruise RRS Discovery cruise D382

The rig was anchored by a 1000 kg dead weight and kept erect by groups of glass spheres distributed along the mooring.

Instruments deployed on the rig

Depth Instrument
1116m Sea-Bird SBE37 SMP MicroCAT (#3931)
1408m Sea-Bird SBE37 SMP MicroCAT (#3911)
1608m Sea-Bird SBE37 SMP MicroCAT (#6115)
1822m Sea-Bird SBE37 SMP MicroCAT (#6116)
2275m Sea-Bird SBE37 SMP MicroCAT (#6117)
2775m Sea-Bird SBE37 SMP MicroCAT (#3928)
3271m Sea-Bird SBE37 SMP MicroCAT (#5243)
3772m Sea-Bird SBE37 SMP MicroCAT (#5239)
4274m Sea-Bird SBE37 SMP MicroCAT (#5778)
4763m Sea-Bird SBE37 SMP MicroCAT (#6119)
5150m InterOcean S4AD current meter (#35612571)
5170m Sea-Bird SBE37 SMP MicroCAT (#6120)

Other Series linked to this Data Activity - 1134658 1134610 1134634 1134695 1134726 1134622 1134646 1134683 1134714 1134671

Cruise

Cruise Name JC064
Departure Date 2011-09-10
Arrival Date 2011-10-09
Principal Scientist(s)Stuart A Cunningham (National Oceanography Centre, Southampton)
Ship RRS James Cook

Complete Cruise Metadata Report is available here


Fixed Station Information

Fixed Station Information

Station NameMid-Atlantic Ridge Array
CategoryOffshore area
Latitude24° 45.00' N
Longitude45° 30.00' W
Water depth below MSL

RAPIDMOC Mid-Atlantic Ridge (MAR) Array

The Mid-Atlantic Ridge Array defines a box in which moorings are deployed either side of the Mid-Atlantic Ridge in the North Atlantic as part of the RAPIDMOC project. The box region has latitudinal limits of 23° N to 26.5° N and longitudinal limits of 40° W to 52.1° W. Moorings have occupied this region since 2004 and are typically deployed for 12 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 4 BPR (4), CM (5), MCTD (20), MMP (1)
2005 CD170 6 BPR (4), CM (6), MCTD (24)
2006 D304 5 BPR (3), CM (3), MCTD (32)
2007 D324 6 BPR (4), CM (3), MCTD (33)
2008 D334 6 BPR (4), CM (3), MCTD (39)
2009 D344 6 BPR (6), CM (3), MCTD (40)
2010 D359 6 BPR (6), CM (5), MCTD (40)
2011 JC064 6 BPR (6), CM (5), MCTD (40)
2012 D382 6 BPR (6), CM (5), MCTD (34)
2014 JC103 6 BPR (6), CM (1), MCTD (34)

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 DIS, MET, NAV, SADCP, SURF -
D279 Hydrographic section CTD, DIS, LADCP, MET, NAV, SADCP, SURF 19
CD170 Array service CTD, DIS, MET, NAV, SADCP, SURF 5
D304 Array service CTD, DIS, MET, NAV, SADCP, SURF 1
D324 Array service CTD, DIS, MET, NAV, SADCP, SURF 3
D334 Array service CTD, DIS, MET, NAV, SADCP, SURF 5
D344 Array service CTD, DIS, MET, NAV, SADCP, SURF 5
D346 Hydrographic section CTD, DIS, LADCP, MET, NAV, SADCP, SURF 21
D359 Array service CTD, DIS, MET, NAV, SADCP, SURF 5
JC064 Array service CTD, DIS, MET, NAV, SADCP, SURF 6
D382 Array service CTD, DIS, MET, NAV, SADCP, SURF 3
JC103 Array service CTD, DIS, MET, NAV, SADCP, SURF 4

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 - 1112859 1112860 1112872 1112884 1112896 1112903 1134425 1134437 1134449 1134450 1134462 1134474 1134486 1134498 1134505 1134517 1134529 1134530 1134542 1134554 1134566 1134578 1134591 1134609 1134610 1134622 1134634 1134646 1134658 1134671 1134683 1134695 1134714 1134726 1134738 1134751 1134763 1134775 1134787 1134799 1264225 1264237 1264249 1264250

Other Cruises linked to this Fixed Station (with the number of series) - CD170 (33) D277 (24) D304 (31) D324 (40) D334 (32) D344 (42) D346 (21) D359 (49) D382 (32) JC103 (4)


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