Metadata Report for BODC Series Reference Number 907217
Metadata Summary
Problem Reports
Data Access Policy
Narrative Documents
Project Information
Data Activity or Cruise Information
Fixed Station Information
BODC Quality Flags
SeaDataNet Quality Flags
Metadata Summary
Data Description |
|||||||||||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||||||||||
Data Identifiers |
|||||||||||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||||||||||
Time Co-ordinates(UT) |
|||||||||||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||||||||||
Spatial Co-ordinates | |||||||||||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||||||||||
Parameters |
|||||||||||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||||||||||
|
Problem Reports
No Problem Report Found in the Database
Data Access Policy
Open Data
These data have no specific confidentiality restrictions for users. However, users must acknowledge data sources as it is not ethical to publish data without proper attribution. Any publication or other output resulting from usage of the data should include an acknowledgment.
If the Information Provider does not provide a specific attribution statement, or if you are using Information from several Information Providers and multiple attributions are not practical in your product or application, you may consider using the following:
"Contains public sector information licensed under the Open Government Licence v1.0."
Narrative Documents
Aanderaa Recording Current Meter Model 9/11
The RCM 9/11 is a family of single-point Doppler recording current meters with different casing options to allow working at depths of up to 300 (RCM 9 LW), 2000 (RCM 9 IW) or 6000 (RCM 11) metres. The recording unit is 51.3 cm or 59.5 cm high (RCM 9 and RCM 11, respectively) with a diameter of 12.8 cm.
The RCM is most commonly deployed in an in-line mooring configuration. As it operates under a tilt up to 35° from vertical, it has a variety of in-line mooring applications by use of surface buoy or sub surface buoy. The instrument is installed in a mooring frame that allows easy installation and removal of the instrument without disassembly of the mooring line. The instrument can also be used for direct reading of the various parameters. This is conveniently done due to its compact design, low drag force and easy handling. Data can be stored internally and read after retrieval or be read in real time on deck by use of the profiling cable.
Meter comprises:
- A Vane Plate (3681) to stabilise the meter during profiling (stops spin).
- Stainless Steel Mooring Frame made to facilitate easy installation and removal of the instrument by use of two knobs.
- Doppler Current Sensor (Current speed sensor) - Range of speed recorded 0-300 cm s-1 with a 0.3 cm s-1 resolution.
- Hall Effect Compass - Direction recorded with 0.35 ° resolution, 5 ° for 0.15 ° tilt and 7.5 ° for 15-35 ° tilt.
- Thermistor (Temperature sensor) - With selectable wide, low, high and Arctic ranges. Standard range -2.70 to 21.77 °C, accuracy 0.05 °C, resolution 0.1% of selected range, 63% response time (12 sec).
- Inductive Cell Conductivity Sensor (optional) - Range 0 to 75 mS cm-1, standard resolution 0.002 mS cm-1.
- Pressure Sensor (optional) - Silicon piezoresistive bridge, standard range 0 to 3500 kPa, resolution 0.1% of range.
- Turbidity Sensor (optional) - Optical back-scatter sensor, resolution 0.1% of full scale, (RCM 11 depth capacity 2000 m).
- Oxygen Sensor (optional) - Oxygen optode, range 0 to 500 µM, resolution < 1µM, response time 60 sec, depth capacity 6000 m.
- Data storage units DSU 2990 and 2990E are standard data storage devices for Aanderaa data collecting instruments.
A built-in quartz clock allows the time of the first measurement to be recorded in the DSU. The measuring system is made up of a self-balancing bridge with sequential measurement of 10 channels and solid state memory. Channel 1 is a fixed reference reading for control purposes and data identification. Channels 2 and 3 represent measurement of current speed and direction. The direction is found by the use of measurements along two orthogonal axis and linking them to true north by use of an internal compass reading. The instrument can operate continuously or in eight intervals from 1 to 120 minutes. At 60-minute recording interval the operating time is more than two years. The current speed and direction are averaged over the measuring interval. Channels 4, 5 and 6 represent temperature, conductivity and pressure respectively.
Further information can be found in the manufacturer's instrument specification.
RAPID - Cape Farewell current meter data processing notes
This document outlines the procedures undertaken to process and quality assure current meter data collected to the east of Cape Farewell, Greenland, as part of the RAPID programme.
Originator's processing
The raw data are downloaded from the instrument and converted to ASCII format. The data are then converted to PSTAR format.
Calculating calibration coefficients
Manufacturers calibrations are applied to the current speed and direction channels.
Two sets of calibration coefficients were employed in the calibration of the pressure, temperature and conductivity data. The first set was obtained either from the manufacturer's calibration coefficients or from the calibration laboratory at the National Oceanography Centre, Southampton (NOCS), hereinafter called laboratory calibrations. The second set, called in-situ calibrations, was obtained by a comparison with CTD data taken on cruise D309. The current meters were strapped to the CTD frame and a full depth CTD cast performed. CTD data obtained during the cast bottle stops were compared to that from the current meter and coefficients derived by fitting a cubic polynomial to the data of the form:
y = A + Bx + Cx2 + Dx3
where A,B,C,D are the coefficients, x is the uncalibrated data and y is the calibrated data.
Both sets of calibration coefficients were employed in converting raw data to physical measurements. Where available, the in-situ temperature and conductivity coefficients were deemed superior as they provided a homogeneous data set.
Data processing
During the conversion from ASCII to PSTAR format the data are calibrated and corrected for magnetic variation. Current velocity components are then derived. Salinity is calculated using the in-situ temperature and conductivity data where available. The pressure for the salinity calculation is chosen on a per instrument basis and is whichever of the two calibration sets that most closely agree with the planned instrument depth/pressure.
The Aanderaa RCM7/8 instruments recorded data throughout each hour (20 samples at 3 minute intervals). Therefore the timestamp of the measurement was selected to be the mid-hour mark. The Aanderaa RCM11 instruments record a burst of measurements just before each hour and each half hour and these were the times assigned to the data measurements.
Quality control
Data were visually inspected for out-lying data and instrument electrical spikes removed.
BODC processing
Data are received after quality checks have been made and calibrations have been applied. The data files are submitted in PSTAR format as one file per instrument.
Once the submitted data files are safely archived, the data undergo standard reformatting and banking procedures:
- The data files are reformatted into a common format, a NetCDF subset.
- Standard parameter codes are assigned that accurately describe the data (see parameter rationalisation and mapping section below).
- Unit conversions are applied, if necessary, so that units are standardised (see parameter rationalisation and mapping section below).
- The data are screened visually and any spikes or instrument malfunctions can be clearly labelled with quality control flags.
- Comprehensive documentation is prepared describing the collection, processing and quality of each data series.
- Detailed metadata and documents are loaded to the database and linked to each series so that the information is readily available to future users.
The following is a summary of what calibrations (laboratory and in-situ) were supplied in which series.
Parameters | Series identifier |
---|---|
Laboratory and in-situ calibrated channels | 906980, 906921*, 906933, 907045, 906957*, 906969*, 906970*, 906982*, 906994*, 907008*, 907021*, 907033*, 907057*, 907069, 907070*, 907082, 907101*, 907113, 907125*, 907137*, 907149*, 907162, 907174 |
In-situ calibrated channels only | 906980, 906945, 907094 |
Laboratory calibrated channels only | 907150, 907186, 907198, 907205, 907217 |
*Only contained laboratory calibrated temperature and pressure.
Parameter rationalisation and mapping
The originator expressed a preference for in-situ over laboratory calibrated channels, so where both in-situ and laboratory calibrated channels were present, the laboratory calibrated channels were dropped from the series. Where in-situ calibrated channels were not available, the laboratory calibrated channels were retained.
The following describes the parameters contained in the series and their mapping to BODC parameter codes. Some parameters e.g. current velocities, were not supplied in every file. Where not supplied and applicable, these channels were calculated by BODC. See parameter derivation section below.
Identifier | Unit | Definition | BODC parameter code | Units | Unit conversion | Comments |
---|---|---|---|---|---|---|
time | seconds | Time in seconds from start of year | AADYAA01/AAFDZZ01 | days | - | - |
pres1/press1/press | db | Pressure from lab calibrations | PRCLCCL1 | db | - | Laboratory calibration. |
pres2/press2 | db | Pressure from in-situ calibrations | PRCLCCI1 | db | - | In-situ calibration. |
cond1 | mmho/cm | Conductivity | CNCLCCL1 | S/m | /10 | Laboratory calibration. |
cond2 | mmho/cm | Conductivity | CNCLCCI1 | S/m | /10 | In-situ calibration. |
temp1/temp | °C | Temperature (IPTS-90) | TMCLCCL1 | °C | - | Laboratory calibration. |
temp2 | °C | Temperature (IPTS-90) | TMCLCCI1 | °C | - | In-situ calibration. |
dir/dirn/dirmag | degrees | True direction | LCDAEL01 | degrees | - | Transferred |
dirnorm | degrees | Direction on plane tilted 32 degrees east from true north | - | - | - | Not transferred |
speed/spd | cm/s | Current speed | LCSAEL01 | cm/s | - | Transferred |
east | cm/s | Eastward current velocity | LCEWEL01 | cm/s | - | If present, transferred |
north | cm/s | Northward current velocity | LCNSEL01 | cm/s | - | If present, transferred |
v122 | cm/s | Eastward current velocity on plane tilted 32 degrees east from true north | - | - | - | Not transferred |
v022 | cm/s | Northward current velocity on plane tilted 32 degrees east from true north | - | - | - | Not transferred |
sal83 | psu | Salinity calculated using in-situ calibrated pressure, temperature and conductivity and UNESCO 1983. | PSCLCCI1 | dimensionless | - | If present, transferred |
potemp | °C | Potential temperature (IPTS-90) | - | - | - | Not transferred |
sal183 | psu | Salinity | - | - | - | Not transferred |
Parameter derivation
The following describes the parameters derived by BODC and their mapping to BODC parameter codes. These parameters were only derived by BODC if they were not supplied by the originators.
BODC parameter code | Units | Variables | Definition | Units | Equation | Comments |
---|---|---|---|---|---|---|
PSCLCCL1 | dimensionless | PRCLCCL1 TMCLCCL1 CNCLCCL1 | Pressure Temperature Conductivity | decibars °C S/m | UNESCO 1983 polynomial for salinity | Salinity calculated from laboratory calibrated pressure, temperature and conductivity |
PSCLCCI1 | dimensionless | PRCLCCI1 TMCLCCI1 CNCLCCI1 | Pressure Temperature Conductivity | decibars °C S/m | UNESCO 1983 polynomial for salinity | Salinity calculated from in-situ calibrated pressure, temperature and conductivity |
LCEWEL01 | cm/s | LCSAEL01 LCDAEL01 | Current speed and true direction | cm/s degrees | speed*sin(direction) | Eastward current velocity |
LCNSEL01 | cm/s | LCSAEL01 LCDAEL01 | Current speed and true direction | cm/s degrees | speed*cos(direction) | Northward current velocity |
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
- To establish a pre-operational prototype system to continuously observe the strength and structure of the Atlantic Meridional Overturning Circulation (MOC).
- To support long-term direct observations of water, heat, salt, and ice transports at critical locations in the northern North Atlantic, to quantify the atmospheric and other (e.g. river run-off, ice sheet discharge) forcing of these transports, and to perform process studies of ocean mixing at northern high latitudes.
- To construct well-calibrated and time-resolved palaeo data records of past climate change, including error estimates, with a particular emphasis on the quantification of the timing and magnitude of rapid change at annual to centennial time-scales.
- To develop and use high-resolution physical models to synthesise observational data.
- To apply a hierarchy of modelling approaches to understand the processes that connect changes in ocean convection and its atmospheric forcing to the large-scale transports relevant to the modulation of climate.
- To understand, using model experimentation and data (palaeo and present day), the atmosphere's response to large changes in Atlantic northward heat transport, in particular changes in storm tracks, storm frequency, storm strengths, and energy and moisture transports.
- To use both instrumental and palaeo data for the quantitative testing of models' abilities to reproduce climate variability and rapid changes on annual to centennial time-scales. To explore the extent to which these data can provide direct information about the thermohaline circulation (THC) and other possible rapid changes in the climate system and their impact.
- To quantify the probability and magnitude of potential future rapid climate change, and the uncertainties in these estimates.
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.
RAPID - Cape Farewell and Eirik Ridge: Interannual to Millennial Thermohaline Circulation Variability
This project was funded under the NERC Rapid Climate Change Programme, grant number NER/T/S/2002/00453. Dr. Sheldon Bacon (Southampton Oceanography Centre) was the Principal Investigator, with co-Investigators from the University of Southampton, Prof. D. A. Stow and Dr. E. J. Rohling. The project started in December 2003 and ended in November 2008.
The project used a combination of hydrography and palaeoceanography measurements to determine the spectrum of variability of the Deep Western Boundary Current, on timescales from days to millennia. The project focused on deglacial to Holocene variability; in particular, seeking to characterise the onset and endings of three cold periods: the Younger Dryas (YD; 12.5-11.5 ka BP), the ~8.2 ka event, and the Little Ice Age (LIA; 16th-19th century AD).
The objectives of the project included:
- Defining the THC response to Holocene climate variability by a highly resolved investigation of palaeoceanographic/climate proxies in sediment cores
- Developing high-resolution sediment proxies for bottom current speed
- Absolute calibration of sediment proxies for bottom current speed
- Defining the relationship between drift construction and the bottom current regime
- Improved definition of present-day ocean circulation and climate
Most of the fieldwork was carried out on 2 cruises in the Cape Farewell and Irminger Sea vicinity:
Cruise | Start | End | Comments |
---|---|---|---|
D298 | 2008-08-23 | 2005-09-05 | Work included mooring deployments, sediment coring, sampling for isotopes and CTD casts |
D309-310 | 2006-08-18 | 2006-09-05 | Work included mooring turn-arounds and CTD casts. |
Data Activity or Cruise Information
Data Activity
Start Date (yyyy-mm-dd) | 2006-08-29 |
End Date (yyyy-mm-dd) | 2008-09-11 |
Organization Undertaking Activity | National Oceanography Centre, Southampton |
Country of Organization | United Kingdom |
Originator's Data Activity Identifier | SB_LM_H#2 |
Platform Category | subsurface mooring |
RAPID Moored Instrument Rig SB_LM_H#2
This rig was deployed as part of the current meter array to the east of Cape Farewell, Greenland, a component of the RAPID programme.
Deployment cruise | RRS Discovery cruise D309-310 |
---|---|
Recovery cruise | RRS Discovery cruise D332 |
The rig was anchored by 700 kg of chain clumps. Buoyancy was provided by 17 inch glass spheres attached to the mooring line in groups over the height of the mooring.
Instruments deployed on the rig
Depth | Instrument |
---|---|
2135 m | Aanderaa RCM11 current meter (#527) |
2255 m | Aanderaa RCM8 current meter (#12293) |
2375 m | Aanderaa RCM11 current meter (#522) |
Related Data Activity activities are detailed in Appendix 1
Cruise
Cruise Name | D309-310 |
Departure Date | 2006-08-18 |
Arrival Date | 2006-09-05 |
Principal Scientist(s) | Sheldon Bacon (National Oceanography Centre, Southampton) |
Ship | RRS Discovery |
Complete Cruise Metadata Report is available here
Fixed Station Information
Fixed Station Information
Station Name | SB_LM_H |
Category | Offshore location |
Latitude | 59° 26.64' N |
Longitude | 41° 9.24' W |
Water depth below MSL | 2421.0 m |
RAPID Mooring Site SB_LM_H
This fixed station forms part of the moored current meter array located to the east of Cape Farewell, Greenland, deployed as part of the RAPID programme.
Period of collection | September 2005 - September 2008 |
---|
Site occupations
Mooring identifier | Deployment date | Recovery date | Parameters measured |
---|---|---|---|
SB_LM_H#1 | 05 Sep 2005 | 23 Aug 2006 | Temperature, conductivity, salinity, pressure and currents |
SB_LM_H#2 | 29 Aug 2006 | 11 Sep 2008 | Temperature, conductivity, salinity, pressure and currents |
Related Fixed Station activities are detailed in Appendix 2
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 |
B | nominal value |
Q | value below limit of quantification |
Appendix 1: SB_LM_H#2
Related series for this Data Activity are presented in the table below. Further information can be found by following the appropriate links.
If you are interested in these series, please be aware we offer a multiple file download service. Should your credentials be insufficient for automatic download, the service also offers a referral to our Enquiries Officer who may be able to negotiate access.
Series Identifier | Data Category | Start date/time | Start position | Cruise |
---|---|---|---|---|
907174 | Currents -subsurface Eulerian | 2006-08-29 14:00:00 | 59.43883 N, 41.15583 W | RRS Discovery D309-310 |
907205 | Currents -subsurface Eulerian | 2006-08-29 14:00:00 | 59.43883 N, 41.15583 W | RRS Discovery D309-310 |
Appendix 2: SB_LM_H
Related series for this Fixed Station are presented in the table below. Further information can be found by following the appropriate links.
If you are interested in these series, please be aware we offer a multiple file download service. Should your credentials be insufficient for automatic download, the service also offers a referral to our Enquiries Officer who may be able to negotiate access.
Series Identifier | Data Category | Start date/time | Start position | Cruise |
---|---|---|---|---|
907137 | Currents -subsurface Eulerian | 2005-09-05 14:30:00 | 59.4495 N, 41.1515 W | RRS Discovery D298 |
907149 | Currents -subsurface Eulerian | 2005-09-05 14:30:00 | 59.4495 N, 41.1515 W | RRS Discovery D298 |
907150 | Currents -subsurface Eulerian | 2005-09-05 14:30:00 | 59.4495 N, 41.1515 W | RRS Discovery D298 |
907174 | Currents -subsurface Eulerian | 2006-08-29 14:00:00 | 59.43883 N, 41.15583 W | RRS Discovery D309-310 |
907205 | Currents -subsurface Eulerian | 2006-08-29 14:00:00 | 59.43883 N, 41.15583 W | RRS Discovery D309-310 |