Metadata Report for BODC Series Reference Number 2022980
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 |
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Data Identifiers |
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Time Co-ordinates(UT) |
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Spatial Co-ordinates | |||||||||||||||||||||||||||||||||||||||||||||
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Parameters |
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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
RD Instruments- Ocean Surveyor 75kHz Vessel mounted ADCP.
Long-Range Mode | ||
---|---|---|
Vertical Resolution Cell Size3 | Max. Range (m)1 | Precision (cm/s)2 |
8m | 520 - 650 | 30 |
16m | 560 - 700 | 17 |
High-Precision Mode | ||
Vertical Resolution Cell Size3 | Max. Range (m)1 | Precision (cm/s)2 |
8m | 310 - 430 | 12 |
16m | 350 - 450 | 9 |
1 Ranges at 1 to 5 knots ship speed are typical and vary with situation.
2 Single-ping standard deviation.
3 User's choice of depth cell size is not limited to the typical values specified.
Profile Parameters
- Velocity long-term accuracy (typical): ±1.0%, ±0.5cm/s
- Velocity range: -5 to 9m/s
- # of depth cells: 1 - 128
- Max ping rate: 0.7
Bottom Track
Maximum altitude (precision <2cm/s): 950m
Echo Intensity Profile
Dynamic range: 80dB
Precision: ±1.5dB
Transducer and Hardware
Beam angle: 30°
Configuration: 4-beam phased array
Communications: RS-232 or RS-422 hex-ASCII or binary output at 1200 - 115,200 baud
Output power: 1000W
Standard Sensors
Temperature (mounted on transducer)
- Range: -5° to 45°C
- Precision: ±0.1°C
- Resolution: 0.03°
Environmental
Operating temperature: -5° to 40°C (-5° to 45°C)*
Storage temperature: -30° to 50°C (-30° to 60°C)*
*later instruments have greater range.
Web Page
Further details can be found on the manufacturer's website or in the specification sheet
Processing by BODC of RRS James Clark Ross JR15007 Vessel Mounted ADCP Data
The data arrived at BODC in one .mat file containing data collected from the 75kHz ship mounted ADCP during cruise JR15007. The data were reformatted to BODC's internal NetCDF format. The following table shows the mapping of variables within the Matlab files to appropriate BODC parameter codes:
Originator's Variable | Originator's Units | BODC Parameter Code | BODC Units | Comment |
---|---|---|---|---|
vel.1 | m/s | LCEWAS01 | cm/s | Conversion *100 applied. Eastward values are positive, and values are corrected for ship's velocity. |
vel.2 | m/s | LCNSAS01 | cm/s | Conversion *100 applied. Northward values are positive, and values are corrected for ship's velocity. |
vel.3 | m/s | LRZAAS01 | cm/s | Conversion *100 applied. Values are corrected for ship's velocity. |
depth | metres | DBINAA01 | metres | - |
nav.txy1(3) | degrees | ALATGP01 | degrees | - |
nav.txy1(2) | degrees | ALONGP01 | degrees | - |
The reformatted data were visualised using the in-house EDSERPLO software. Suspect data were marked by adding an appropriate quality control flag, missing data by both setting the data to an appropriate value and setting the quality control flag.
Processing by Originator of RRS James Clark Ross JR15007 Vessel Mounted ADCP Data
The following was taken from the JR15007 cruise report. Data were collected using a Teledyne RDI Ocean Surveyor 75 kHz vessel mounted ADCP. For more detailed information please refer to the cruise report.
Data were acquired using the RD Instruments VmDas software package version 1.42.
ADCP setup
Variable | Setting |
---|---|
Number of Bins | 100 |
Bin size | 16 m |
Blanking distance | 8 m |
Transducer depth | 6.3 m |
Processing mode | Single-ping mode: bottom-tracking and water-tracking |
Maximum range | 800 m |
Post-processing
The data were processed using a series of MATLAB scripts. The ADCP is fed with navigation and attitude date from the Seatex GPS system. The processing route can be summarised as copying the raw files, converting them into a working format, merging navigation data, deriving absolute velocities, and quality control.
Calibration
The VMADCP operated continuously in narrowband mode. Misalignment angle and amplitude factors were estimated using water track calibration over the duration of the cruise (approximately 30 days). The estimated values for both misalignment angle and amplitude factors appeared to be stable through time, consequently only a single value was used for each parameter during the processing (-0.894 misalignment ; 1.011 amplitude).
Calibration parameters estimated using water track for JR15007:
Parameters | Mean | Median | Standard Deviation |
---|---|---|---|
Misalignment angle | 1.010656 | 1.010821 | 0.007754 |
Amplitude factor | -0.8935 | -0.8938 | 0.4452 |
Project Information
A nutrient and carbon pump over mid-ocean ridges (RidgeMix)
RidgeMix is a five year (August 2014 to February 2019) research programme which received funding from the Natural Environment Research Council (NERC). The aim of the programme was to address the problem of how deep nutrients are transported into the surface waters in mid-latitudes, by testing a new view: tides passing over the mid-Atlantic ridge generate enhanced turbulence and mixing, which in turn provides a nutrient supply to the upper thermocline waters. These nutrients are then transported horizontally along density surfaces over the western side of the basin, probably being swept along the Gulf Stream and eventually passing into the winter mixed surface layer. When this surface layer shallows and warms in spring, the nutrients are then available to the phytoplankton.
Fieldwork involved collecting measurements of the turbulence and nutrient concentrations over and adjacent to the Mid-Atlantic Ridge, using a novel long-term moored array of instruments along the ridge, deployed over a five-week research cruise. Sampling was done sufficiently quickly to resolve tidal changes in currents and mixing over the ridge. A second component of the fieldwork will use computer models of circulation in the Atlantic to explore the wider implications of the fieldwork observations, to determine whether or not mixing over the mid-Atlantic ridge really does provide enough nutrients to explain the phytoplankton production in the mid-latitude North Atlantic.
RidgeMix was a collaborative project involving five organisations, of which three were UK based and two were US based. The project was led by the Professor Jonathan Sharples, University of Liverpool, Earth, Ocean and Ecological Sciences. Collaborators were:
Data Activity or Cruise Information
Cruise
Cruise Name | JR15007 |
Departure Date | 2016-05-25 |
Arrival Date | 2016-07-10 |
Principal Scientist(s) | Jonathan Sharples (National Oceanography Centre, Liverpool) |
Ship | RRS James Clark Ross |
Complete Cruise Metadata Report is available here
Fixed Station Information
No Fixed Station Information held for the Series
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 |