Metadata Report for BODC Series Reference Number 1756685
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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Time Co-ordinates(UT) |
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Spatial Co-ordinates | |||||||||||||||||||||||||||||||||||||||||||||||||
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Parameters |
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Problem Reports
BODC have been informed by NMF that during DY052 there was a problem with the Meteorology data source converting digital to analogue.
BODC could see suspect features in the wind channels and so all have been flagged as suspect. (BODC assessment)
RRS Discovery DY052 Meteorology Quality Report
Light sensors
All PAR and TIR channels display consistent negative readings during night time. This most likely results from excessive loss of radiation after sunset, which suggests that day-time data recorded during cloud cover should also be treated with caution. Another explanation would be that outdated calibrations added an offset to the data. All negative PAR and TIR data were flagged. (BODC assessment)
There appeared to be several instances of shading between the original port/starboard PAR and TIR sensor pairs. This issue was solved by creating a new, unique channel for PAR and TIR respectively, composed of the maximum values per data cycle between each pair of sensors. (BODC assessment)
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
Gill Instruments Windsonic Anemometer
The Gill Windsonic is a 2-axis ultrasonic wind sensor that monitors wind speed and direction using four transducers. The time taken for an ultrasonic pulse to travel from the North to the South transducers is measured and compared with the time for a pulse to travel from South to North. Travel times between the East and West transducers are similarly compared. The wind speed and direction are calculated from the differences in the times of flight along each axis. This calculation is independent of environmental factors such as temperature.
Specifications
Ultrasonic output rate | 0.25, 0.5, 1, 2 or 4 Hz |
Operating Temperature | -35 to 70°C |
Operating Humidity | < 5 to 100% RH |
Anemometer start up time | < 5 s |
Wind speed | |
Range | 0 to 60 m s-1 |
Accuracy | ± 2% at 2 m s-1 |
Resolution | 0.01 m s-1 |
Response time | 0.25 s |
Threshold | 0.01 m s-1 |
Wind direction | |
Range | 0 to 359° |
Accuracy | ± 3° at 12 m s-1 |
Resolution | 1° |
Response time | 0.25 s |
Further details can be found in the manufacturer's specification sheet.
Kipp and Zonen Pyranometer Model CM6B
The CM6B pyranometer is intended for routine global solar radiation measurement research on a level surface. The CM6B features a sixty-four thermocouple junction (series connected) sensing element. The sensing element is coated with a highly stable carbon based non-organic coating, which delivers excellent spectral absorption and long term stability characteristics. The sensing element is housed under two concentric fitting Schott K5 glass domes.
Specifications
Dimensions (W x H) | 150.0 mm x 91.5 mm |
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Weight | 850 grams |
Operating Temperature | -40°C to +80°C |
Spectral Range | 305 - 2800 nm (50% points) |
Sensitivity | 9 -15 µV/W/m2 |
Impedance (nominal) | 70 - 100 ohm |
Response Time (95%) | 30 sec |
Non-linearity | < ± 1.2% (<1000 W/m2) |
Temperature dependence of sensitivity | < ± 2% (-10 to +40°C) |
Zero-offset due to temperature changes | < ± 4 W/m2 at 5 K/h temperature change |
RRS Discovery DY052 Meteorology Instrumentation
The meteorological suite of sensors was located on the forecastle deck, at approximately 19 m above sea level. The anemometer orientation was 0° on the bow.
Manufacturer | Model | Serial number | Last manufacturer's calibration date | Comments |
Skye | SKE 510 | 28561 | 30/04/2015 | Port |
Skye | SKE 510 | 28556 | 11/09/2015 | Starboard |
Kipp and Zonen | CM 6B | 973134 | 19/03/2015 | Port |
Kipp and Zonen | CM 6B | 962276 | 13/11/2014 | Starboard |
Gill | Windsonic | 10280018 | - | No calibration required |
Vaisala | Humidity and Temperature Probe HMP155 | K0950056 | 10/06/2015 | No calibration required |
Vaisala | PTB110 Barometer Air pres | L0650612 | 06/02/2015 | No calibration required |
Skye Instruments PAR Energy Sensor Model SKE 510
The SKE 510 is suitable for measuring photosynthetically active radiation (PAR) from natural or artificial light sources. The sensor is fully waterproof and guaranteed submersible to 4m depth, and indoor versions are also available.
The instrument uses a blue-enhanced planar diffused silicon detector to measure energy (in W m-2) over the 400-700 nm waveband. It has a cosine-corrected head and a square spectral response. The sensor can operate over a temperature range of -35 to 70 °C and a humidity range of 0-100% RH.
Specifications
Sensitivity (current) | 1.5µA or 100 W m-2 |
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Sensitivity (voltage) | 1mV or 100 W m-2 |
Working Range | 0-5000 W m-2 |
Linearity error | 0.2% |
Absolute calibration error | typ. less than 3% 5% max |
Response time - voltage output | 10 ns |
Cosine error | 3% |
Azimuth error | less than 1% |
Temperature co-efficient | ±0.1% per °C |
Internal resistance - voltage output | c. 300 ohms |
Longterm stability | ±2% |
Material | Dupont 'Delrin' |
Dimensions | 34 mm diameter 38mm height |
Cable | 2 core screened 7 - 2 - 2C |
Sensor Passband | 400 - 700 nm |
Detector | Silicon photocell |
Filters | Glass type and/or metal interference |
Vaisala PTB110 barometer
An industrial, analog barometer which uses a silicon capacitive sensor (BAROCAP). The sensor produces either frequency or voltage output and is mountable on a (35 mm wide) DIN rail.
Operating ranges (1 hPa = 1 mbar)
Pressure ranges | 500 ... 1100 hPa 600 ... 1100 hPa 800 ... 1100 hPa 800 ... 1060 hPa 600 ... 1060 hPa |
Temperature range | -40 ... +60 °C (-40 ... +140 °F) |
Humidity range | non-condensing |
General
Output voltage | 0 ... 2.5 VDC 0 ... 5 VDC |
Output frequency | 500 ... 1100 Hz |
Resolution | 0.1 hPa |
Accuracy
Linearity* | ±0.25 hPa |
Hysteresis* | ±0.03 hPa |
Repeatability* | ±0.03 hPa |
Pressure calibration uncertainty** | ±0.15 hPa |
Accuracy at +20 °C*** | ±0.3 hPa |
Total accuracy at: | |
+15 ... +25 °C (+59 ... +77 °F) 0 ... +40 °C (+32 ... +104 °F) -20 ... +45 °C (-4 ... +113 °F) -40 ... +60 °C (-40 ... +140 °F) | ±0.3 hPa ±0.6 hPa ±1.0 hPa ±1.5 hPa |
* Defined as ±2 standard deviation limits of end-point non-linearity, hysteresis error or repeatability error.
** Defined as ±2 standard deviation limits of inaccuracy of the working standard including traceability to NIST.
*** Defined as the root sum of the squares (RSS) of end-point non-linearity, hysteresis error, repeatability error and calibration uncertainty at room temperature when using voltage output.
More detailed information can be found in the manufacturer's data sheet and user's guide.
Vaisala Temperature and Relative Humidity HMP Sensors
A family of sensors and instruments (sensors plus integral displays or loggers) for the measurement of air temperature and relative humidity. All are based on a probe containing a patent (HUMICAP) capacitive thin polymer film capacitanece humidity sensor and a Pt100 platinum resistance thermometer. The probes are available with a wide range of packaging, cabling and interface options all of which have designations of the form HMPnn or HMPnnn such as HMP45 and HMP230. Vaisala sensors are incorporated into weather stations and marketed by Campbell Scientific.
All versions operate at up to 100% humidity. Operating temperature ranges vary between models, allowing users to select the version best suited to their requirements.
Further details can be found in the manufacturer's specification sheets for the HMP 45 series, HMP 70 series and HMP 230 series.
RRS Discovery DY052 Meteorology processing procedures
Originator's Data Processing
SurfMet
Ship speed, position and heading from the bst navigation file were merged onto the wind data in the surfmet stream. The absolute wind speed is calculated and vector averaged with mtruew_01.m. As with bestnav processing, this is re-run for the entire cruise each time the data are updated. The output files from this processing are:
data/met/surfmet/met_dy052_true.nc data/met/surfmet/met_dy052_trueav.nc
The latter file is reduced to 1-minute averages, with correct vector averaging when required. In order to avoid ambiguity, variable units are explicit in whether wind directions are towards or from the direction in question. Although the header originally reported the speed in knots, comparison against the on-board live streams showed that the units were in fact m/s.
SurfLight
PA irradiance and thermal-IR data are found in the surlight stream, which also contains surface pressure. These streams were ingested and stored, but no further processing was undertaken.
The daily Mstar Met files provided to BODC were used for BODC processing. Data were additionally logged into the RVS Level-C format files and TECHSAS which have been archived at BODC. Relative wind speed and direction were loaded from the TECHSAS source files.
For more detailed information on the Originator's underway data processing, please see the cruise report, p56-62.
Files delivered to BODC
Filename | Content description | Format | Interval | Start date/time (UTC) | End date/time (UTC) | Comments |
met_dy052_trueav.nc | relative wind speed, relative wind direction | Mstar | 60 seconds. | 05/06/2016 09:00:00 | 23/06/2016 20:03:00 | |
met_light_dy052_01.nc | Air pressure, PAR, TIR | Mstar | 1 second. | 05/06/2016 09:00:01 | 23/06/2016 20:03:16 | |
met_dy052_01.nc | Humidity, air temperature | Mstar | 1 second. | 05/06/2016 09:00:01 | 23/06/2016 20:03:16 | |
*-*-MET-DY-SM_DY1.SURFMETv2 | relative wind speed, relative wind direction | Mstar | ~1 second. | 05/06/2016 14:13:50 | 23/06/2016 20:03:16 |
BODC Data Processing
The data were reformatted to BODC internal format using standard banking procedures. Data were averaged at 60 second intervals. The following table shows how variables within the file were mapped to appropriate BODC parameter codes:
met_dy052_trueav.nc
Originator's variable | Originator's units | Description | BODC Code | BODC Units | Unit conversion | Comments |
ship_u | m/s | Ship eastward velocity | Not transferred. Derived by BODC. | |||
ship_v | m/s | Ship northward velocity | Not transferred. Derived by BODC. | |||
ship_spd | m/s | Ship's speed | Not transferred | |||
ship_dir | degrees | ship direction | Not transferred. Transferred from bestnav. | |||
ship_hdg | degrees | ship heading | Not transferred. Transferred from bestnav. | |||
truwind_u | m/s | true wind eastward velocity | Not transferred | |||
truwind_v | m/s | true wind northward velocity | Not transferred | |||
trwind_dir | degrees | True wind direction | EWDASS01 | degrees | none | Not transferred. Derived by BODC. |
truwind_spd | m/s | True wind speed | EWSBSS01 | m/s | none | Not transferred. Derived by BODC. |
relwind_u | m/s | Relative east component wind velocity | Not transferred. | |||
relwind_v | m/s | Relative north component wind velocity | Not transferred. | |||
relwind_spd | m/s | relative wind speed | Not transferred. Sourced from TECHSAS. | |||
relwind_direarth | degrees_to relative to earth | degrees_to relative to earth | Not transferred. | |||
relwind_dirship | degrees relative to ship 0 = towards bow | degrees relative to ship 0 = towards bow | Not transferred. Sourced from TECHSAS. | |||
lat | degree_north | degree_north | Not transferred. Transferred from bestnav. | |||
long | degree_east | degree_east | Not transferred. Transferred from bestnav. | |||
distrun | km | distance travelled | DSRNCV01 | km | none | Not transferred. Derived by BODC. |
time | seconds since 01/01/2016 | Measure timestamp | Not transferred |
met_light_dy052_01.nc
Originator's variable | Originator's units | Description | BODC Code | BODC Units | Unit conversion | Comments |
ptir | Volt x 105 | Port total irradiance | CVLTRP01 | Volts | /100000 | |
stir | Volt x 105 | Starboard total irradiance | CVLTRS01 | Volts | /100000 | |
ppar | Volt x 105 | Port side PAR sensor | DVLTRPSD | Volts | /100000 | |
spar | Volt x 105 | Port side starboard sensor | DVLTRSSD | Volts | /100000 | |
pres | mbar | Atmospheric pressure | CAPHTU01 | millibar | none | |
time | seconds since 01/01/2016 | Measure timestamp | Not transferred |
met_dy052_01.nc
Originator's variable | Originator's units | Description | BODC Code | BODC Units | Unit conversion | Comments |
Direct | degree | True wind direction | Not transferred. | |||
speed | m/s | True wind speed | Not transferred. | |||
airtemp | degree celsius | Air temperature | CDTAZZ01 | degrees celsius | none | |
humid | % | Relative air humidity | CRELZZ01 | % | none | |
time | seconds since 01/01/2016 | Measure timestamp | Not transferred |
yyyymmdd-050010-MET-DY-SM_DY1.SURFMETv2
Originator's variable | Originator's units | Description | BODC Code | BODC Units | Unit conversion | Comments |
direct | degrees | Apparent wind direction | ERWDSS01 | degrees | none | |
speed | m/s | Apparent wind speed | ERWSSS01 | m/s | none | |
airtemp | degree celsius | Air temperature | Not transferred. | |||
humid | % | Relative air humidity | Not transferred. | |||
time | days since 1899-12-30 00:00:00 UTC | Acquisition time | Not transferred |
All data expressed at measurement altitude.
Screening
All the reformatted data were visualised using the in-house EDSERPLO software. Suspect data were marked by adding an appropriate quality control flag.
Calibrations
Field Calibrations
No field calibrations were applied to the data at BODC.
Manufacturers Calibrations
PAR/TIR
The following manufacturer's calibrations were applied to the PAR and TIR light sensors using:
y (W m -2 ) = (a x 10 6 )/b
where 'a' is the raw data in volts and 'b' is the calibration offset (µV per W m -2 ) as shown below.
Sensor | Serial no | location | offset (µV per W m -2 ) |
PAR | 28561 | Port | 10.05 |
PAR | 28556 | Starboard | 9.783 |
TIR | 962276 | Starboard | 10.14 |
TIR | 973134 | Port | 10.97 |
Subsequently, the maximum values between the port-side and starboard-side sensor pairs were extracted into single new PAR and TIR data channels to eliminate the effects of shading. These resulted in the BODC derived parameters DWIRRXMX and CSLRR1XS.
Absolute wind speed and direction
Relative wind speed and direction were corrected for the ship's heading and speed using the POS MV gyro heading, ship velocities (calculated at BODC from the main positional channels) and an anemometer orientation of 0° on the bow, thus obtaining the BODC derived absolute wind speed and direction parameters, with codes EWSBSS01 and EWDASS01 respectively.
Air pressure
A manufacturer's calibration was not applied to the barometer because there was no significant offset reported on the certified calibration certificate.
Air temperature and humidity
Manufacturer's calibrations were not applied to the temperature and humidity probe because there were no significant offsets reported on the certified calibration certificate.
Project Information
No Project Information held for the Series
Data Activity or Cruise Information
Cruise
Cruise Name | DY052 |
Departure Date | 2016-06-07 |
Arrival Date | 2016-06-24 |
Principal Scientist(s) | Stefan F Gary (Scottish Association for Marine Science) |
Ship | RRS Discovery |
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 |
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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 |
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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 |