Metadata Report for BODC Series Reference Number 1161066


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 Dr Miguel Morales Maqueda
Originating Organization Proudman Oceanographic Laboratory (now National Oceanography Centre, Liverpool)
Processing Status banked
Project(s) RAPID-WAVE
RAPID-WATCH
 

Data Identifiers

Originator's Identifier RS1LM#2/2165
BODC Series Reference 1161066
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2009-10-02 14:20
End Time (yyyy-mm-dd hh:mm) 2010-12-16 13:00
Nominal Cycle Interval 300.0 seconds
 

Spatial Co-ordinates

Latitude 42.85371 N ( 42° 51.2' N )
Longitude 61.63199 W ( 61° 37.9' W )
Positional Uncertainty Unspecified
Minimum Sensor Depth 1000.0 m
Maximum Sensor Depth 1000.0 m
Minimum Sensor Height 100.0 m
Maximum Sensor Height 100.0 m
Sea Floor Depth 1100.0 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-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

RAPID WAVE Sea-Bird MicroCAT data processing document

This document outlines the procedures undertaken to process and quality assure the MicroCAT data collected under the RAPID WAVE project.

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

The pressure (when applicable) and temperature-conductivity data were calibrated according to the following prescription: For each instrument, two calibration casts were performed. One previous to instrument deployment and one after recovery. Regression coefficients derived from these casts were used to calibrate the pressure, temperature and conductivity from the MicroCATs. A calibration cast consists in clamping one or more MicroCATs to the CTD rosette and carrying out simultaneous measurements with both the MicroCATs and the on-board calibrated CTD instrument package. Measurements taken during the upward part of the cast by stationing the rosette at a particular depth for an interval of between 10 and 15 minutes are used to obtain linear calibration coefficients for temperature, conductivity and, if applicable, pressure. Because the reference CTD takes samples at 24 Hz, while the MicroCATs sample at between 15 and 30 second intervals, the MicroCAT measurements are interpolated linearly in time to obtain as many samples as the reference CTD. As the reference CTD does not have measurements of the time of day, the synchronisation between the measurements of the CTD and the MicroCAT instruments is approximate. However, this calibration procedure is possible because the plateaus of pressure are easily detectable by eye. The calibration coefficients derived from the pre-deployment and post-recovery casts can then be combined to provide calibration coefficients that vary linearly in time over the period when the instrument was moored.

Calibration procedure and salinity computation

The 10-15 minute plateaus were determined and for each plateau correlation coefficient R and regression coefficients A and B were computed:

CTD = A * MC + B

This procedure was applied to each of the three properties: T, C and P (where available). Although care was taken to ensure that no data points outside the plateaus were employed in the analysis, some scatter plots revealed obvious outliers. They were removed as follows:

In the cases where R was less than 0.75, the data point, which was the farthest from the linear trend, was rejected. The correlation coefficient and the coefficients of the linear approximation were then re-computed. The iterative process continued until the correlation coefficient became at least 0.75. Next, the despiked plateaus were concatenated and new values of A and B were determined from the data merged in such manner. These values of A and B were then applied to the entire record from the corresponding instrument as:

MC_calibrated = A * MC_raw + B

Next, outliers were eyeballed and removed. These happened to be only in conductivity records: the temperature and pressure data were clean. The calibrated records of T, C and P (where P was measured) were then used for the computation of salinity, using the UNESCO 1983 algorithm of Fofonoff and Millard (1983) as implemented by the CSIRO seawater Matlab package version 3.2. Despite the fact that the conductivity had been despiked and the series of T and P were spikeless, there were some salinity spikes after the computation. They were identified by eye and removed.

BODC were not supplied with the calibration coefficient values, however, these can be calculated using the raw and corresponding calibrated data values. Raw data can be obtained from BODC if this is required by the user.

BODC processing

The data files were submitted in ASCII format as one file per instrument. Once the submitted data files are safely archived, the data undergo standard reformatting and banking procedures:

Parameter mapping

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

Originator's variable Originator's units BODC parameter code BODC parameter definition BODC units Unit conversion Comments
Temperature (edited and calibrated) deg C TEMPPR01 Temperature of the water body deg C - -
Conductivity (edited and calibrated) Siemens/metre CNDCPR01 Electrical conductivity of the water body by in-situ conductivity cell Siemens/metre - -
Salinity PSU PSALPR01 Practical salinity of the water body by conductivity cell and computation using UNESCO 1983 algorithm - - See salinity computation (above)
Pressure (edited and calibrated) decibars PREXMCAT Pressure (measured variable) exerted by the water body by semi-fixed moored SBE MicroCAT decibars - Only included in the final data file if MicroCAT was equipped with a pressure sensor
Temperature from the MicroCAT deg C - - - - Not transferred
Conductivity from the MicroCAT Siemens/metre - - - - Not transferred
De-spiked salinity PSU - - - - Not transferred
Pressure from the MicroCAT decibars - - - - Not transferred
Estimated pressure decibars - - - - Not transferred
Calibrated estimated pressure decibars - - - - Not transferred
Flag where temperature, conductivity or pressure data were edited - - - - - Not transferred
Flag for spiked salinity - - - - - Used to populate the flag channel of PSALPR01

Project Information

RAPID Western Atlantic Variability Experiment (WAVE)

Introduction

The RAPID WAVE project began in 2004 as an observational component of the U.K Natural Environment Research Council's RAPID Climate Change Programme in the western North Atlantic Ocean. In 2008, funding to continue RAPID WAVE was secured through the continuation programme, RAPID-WATCH, which is due to end in 2014.

The RAPID WAVE team brings together scientists at the National Oceanography Centre in Liverpool. Between 2004 and 2010, the RAPID WAVE team also contributed to the Line W mooring array, joining colleagues from the U.S. Line W is a U.S-led initiative used to monitor the North Atlantic Ocean's deep western boundary current whilst being funded through the U.S National Science Foundation and has been active since October 2001. It brings together scientists from Woods Hole Oceanographic Institution (WHOI) and Lamont-Doherty Earth Observatory (LDEO). Users of these data are referred to the Line W Project Website for more information.

In 2007, further collaboration was established with scientists at the Bedford Institute of Oceanography (BIO). This arrangement was formalised and continues under RAPID-WATCH. Smaller scale collaboration with scientists at the Instituto Espanol de Oceanografia (IEO) during RAPID-WATCH saw additional RAPID WAVE observational work in the eastern North Atlantic Ocean. This work commenced in 2009 as part of the RAPID WAVE RAPIDO campaign.

Scientific Rationale

The primary aim of the RAPID WAVE project is to develop an observing system that will identify the propagation of overturning signals, from high to low latitudes, along the western margin of the North Atlantic. It specifically aims to monitor temporal changes in the Deep Western Boundary Current and reveal how coherent the changes are along the slope. Ultimately it is envisaged that this will enable scientists to develop a better understanding of larger-scale overturning circulation in the Atlantic, and its wider impacts on climate.

Fieldwork

The fieldwork aspect of the project was to deploy arrays of Bottom Pressure Recorders (BPRs) and CTD moorings along specified satellite altimeter groundtracks off the eastern continental slope of Canada and the United States. In 2004, fieldwork focused on three array lines. Line A was established heading south west from the Grand Banks, whilst the Line B array ran south east on the continental slope of Nova Scotia. The third line, Line W, was an established hydrographic array on the continental slope of New England, serviced by Woods Hole Oceanographic Institute (WHOI), to which RAPID WAVE contributed BPR instrumentation.

The original intention was that each array would be serviced by a cruise every two years. However, following a very poor return rate of instrumentation during the first servicing cruise of Lines A and B in 2006, this plan was modified significantly, and the decision made to abandon work on Line A. In 2007, additional logistical support from Canada's Bedford Institute of Oceanography (BIO) enabled Line B to be serviced again after just one year of deployment, with a much improved recovery record.

The transition from RAPID to RAPID-WATCH funding marked significant changes to the RAPID WAVE observational system. Line B was abandoned and a joint array with BIO, known as the RAPID Scotia Line, to the south west was developed. This line receives annual servicing by BIO, with cruise participation from the RAPID WAVE team.

The servicing of RAPID WAVE BPRs on Line W remained a biennial activity during the RAPID and RAPID-WATCH programmes.

A small number of BPR deployments have also taken place off the coast of Spain as part of the RAPIDO element of RAPID WAVE.

Instrumentation

Types of instruments and measurements:

Contacts

Collaborator Organisation Project
Prof. Chris M. Hughes National Oceanography Centre, U.K RAPID WAVE
Dr. Miguel Angel Morales Maqueda National Oceanography Centre, U.K RAPID WAVE
Dr. Shane Elipot National Oceanography Centre, U.K RAPID WAVE
Dr. John M. Toole Woods Hole Oceanographic Institution, U.S Line W
Dr. Igor Yashayaev Bedford Institute of Oceanography, Canada -

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) 2009-10-02
End Date (yyyy-mm-dd) 2010-12-16
Organization Undertaking ActivityProudman Oceanographic Laboratory (now National Oceanography Centre, Liverpool)
Country of OrganizationUnited Kingdom
Originator's Data Activity IdentifierRS1LM#2
Platform Categorysubsurface mooring

RAPID Moored Instrument Rig RS1LM#2

This rig was deployed as part of the Halifax/Line RS array of the RAPID WAVE project.

Deployment cruise CCGS Hudson Cruise HUD09048 Leg1
Recovery cruise CCGS Hudson Cruise HUD10049

The rig was anchored by a cast iron sinker and kept erect by groups of buoyancy spheres attached along the mooring.

Instruments deployed on the rig

All nominal depths have been sourced from the deployment cruise report.

Depth Instrument
1000 m Sea-Bird SBE37 SM MicroCAT (#2165)
1050 m RDI Workhorse ADCP (#11432)
1099 m RBR BPR DR-1050 (#14581)
1099 m Sea-Bird SBE53 BPR (#24)

Other Series linked to this Data Activity - 1192919 1176305

Cruise

Cruise Name HUD09048 Leg1
Departure Date 2009-09-26
Arrival Date 2009-10-03
Principal Scientist(s)Edward Horne (Bedford Institute of Oceanography)
Ship CCGS Hudson

Complete Cruise Metadata Report is available here


Fixed Station Information

Fixed Station Information

Station NameRAPID WAVE Site RS1
CategoryOffshore location
Latitude42° 50.96' N
Longitude61° 37.86' W
Water depth below MSL1116.0 m

RAPID Mooring Site RS1

This fixed station forms part of the RAPID Scotia mooring array located on the Scotian Shelf, Nova Scotia. The RAPID Scotia array is deployed as part of the RAPID WAVE project under the RAPID-WATCH programme. This array acts as an extension to the existing Halifax Line, maintained by Bedford Institute of Oceanography (BIO), Canada.

Period of collection October 2008 - present

Site occupations

Mooring identifier Mooring type Deployment date Recovery date Parameters measured
RS1LM#1 Line Mooring 03 Oct 2008    28 Sep 2009 Temperature, conductivity, salinity, pressure, bottom pressure and currents
RS1LM#2 Line Mooring 02 Oct 2009 16 Dec 2010 Temperature, conductivity, salinity, pressure, bottom pressure and currents
RS1LM#3 Line Mooring 19 Dec 2010    24 Sep 2011 Temperature, conductivity, salinity, pressure, bottom pressure, oxygen and currents
RS1LM#4 Line Mooring 29 Sep 2011    05 Apr 2013 Temperature, conductivity, salinity, pressure, bottom pressure and currents

Other Series linked to this Fixed Station for this cruise - 1176305 1192919

Other Cruises linked to this Fixed Station (with the number of series) - HUD08037 Leg1 (3) HUD10049 (4) HUD11043 Leg1 (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