Metadata Report for BODC Series Reference Number 1222911
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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Problem Reports
No Problem Report Found in the Database
RRS James Clark Ross AMT6 (JR32) Meteorological Data Processing Procedures
Data quality report
Users should be cautious when using ship-borne wind measurements. Although the relative wind data have been corrected for ship's heading and speed, they are still sensitive to shielding effects. Users can consult the ship's E-W and N-S speed alongside the wind speed and direction.
According to the AMT5 cruise report, the Kipp and Zonen CM-10 pyranometer was installed on the first stage island of the JCR foremast. The instrument was not mounted on gimbals and suffered from shading by the foremast. The data may also be affected by reflection that may occur from the white paint of the mast structure. This effect is difficult to correct for (AMT5 cruise report p17) and may affect the data for this cruise.
Data Access Policy
Public domain 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.
The recommended acknowledgment is
"This study uses data from the data source/organisation/programme, provided by the British Oceanographic Data Centre and funded by the funding body."
Narrative Documents
Kipp and Zonen CM10/CM11/CM14 pyranometer
General Information
The CM10 is the first release of Kipp and Zonen's secondary standard pyranometer, without sun screen and levelling feet. Later this became standard and the instrument was called CM11.
The pyranometer CM 11 is designed for measuring the irradiance (radiant flux,Watt/m2) on a plane surface, which results from the direct solar radiation and from the diffuse radiation incident from the hemisphere above. Because the CM 11 exhibits no tilt dependence it can measure solar radiation on surfaces inclined as well. In the inverted position reflected solar radiation can be measured.
The albedometer CM14 is based on two CM11 sensors and is suitable for the measurement of net global radiation and/or albedo over surfaces of different nature.
Physical Properties
The pyranometer CM 11 is provided with a thermal detector. This type of detector responds to the total power absorbed and theoretically it is non-selective as to the spectral distribution of the radiation. This implies that the naked thermal detector is also sensitive to long wave infrared radiation (thermal radiation λ > 3000 nm) from the environment. (e.g. the inner dome) The radiant energy is absorbed by a black painted disk. The heat generated flows through a thermal resistance to the heat sink (the pyranometer body). The temperature difference across the thermal resistance of the disk is converted into a voltage. The rise of temperature is easily affected by wind, rain and thermal radiation losses to the environment ('cold' sky). Therefore the detector is shielded by two glass domes. Glass domes allow equal transmitting of the direct solar component for every position of the sun on the celestial sphere. The spectral range of the pyranometer is limited by the transmission of the glass. A desiccator in the body prevents dew on the inner side of the domes, which can cool down considerably, at clear windless nights.
Construction
The sensing element of the pyranometer CM 11 is a black painted ceramic (Al2O3) disk. 100 thermocouples forming a thermopile are imprinted on it using thick film techniques. Only the border of the disk is in good thermal contact with the pyranometer body (heat sink), and along this border the 100 cold junctions are located. The 100 hot junctions are near the centre in a rotational symmetric arrangement. This fact plus a proper levelling of the sensor related to the spirit level results in a low azimuth error.
Specifications
Operating Temperatures | A thermistor is applied in the electric circuit to keep the sensitivity constant at least for temperatures between -10 °C and + 40 °C. |
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Spectral range | 310 - 2800 nm (50% points) 340 - 2200 nm (95% points) |
Irradiance | 0 - 1400 W/m2 (max. 4000 W/m2) |
Non-stability | <±0.5% sensitivity change per year |
Spectral selectivity | ±2% (0.35 µm to 1.5 µm) |
The specified directional response includes (as relative errors) | |
Cosine response | max. ±1% deviation from ideal at 60° solar zenith angle in any azimuth direction. |
max. ±3% deviation from ideal at 80° solar zenith angle in any azimuth direction. | |
Weight | 830 g |
Dimensions | W x H 150 x 95 mm |
Accuracy
Unfortunately the sensitivity is cross-correlated to a number of parameters as temperature, level of irradiance, vector of incidence, etc. The upper limiting values of the resulting sensitivity variations are listed in the specifications. It classifies the pyranometer CM11 as a 'secondary standard' according to the classification of the World Meteorological Organization. Normally, the supplied sensitivity figure is used to calculate the irradiances. If the conditions differ from calibration conditions, errors in the calculated irradiances must be expected. For a secondary standard instrument the WMO expects maximum errors in the hourly radiation totals of 3%. In the daily total an error of 2% is expected, because some response variations cancel out each other if the integration period is long. These errors can be reduced further if the actual sensitivity of the pyranometer is used by the conversion of voltage to irradiance. The actual sensitivity can be calculated when it is a well-known function of simply measured parameters (sometimes called transfer function or sensitivity function). This is especially convenient in connection with a programmable data acquisition system. For the CM11 the effect of each parameter on the sensitivity can be shown separately, because the parameters show less interaction.
More information on the CM10/CM11/CM14 may be found in the Kipp and Zonen CM11/14 manual.
Vector Instruments air temperature sensor
Instrument used to measure air temperature. The model is unknown.
Vector Instruments cup anemometer
Instrument used to measure wind speed. The model is unknown. It is assumed to consist of a 3-cup rotor, a precision ball-race mounted shaft and internal modules and components to provide electrical output signals. The outline and mechanical design of Vector Instruments cup anemometers, common to the A100 series, has remained largely unchanged since the introduction of the original Porton Anemometer in 1972.
Vector Instruments wind vane
Instrument used to measure wind direction. The model is unknown. It is assumed to consist of a free-rotating fin that is mounted on a shaft and internal modules and components to provide electrical output signals.
Didcot DRP-1 PAR sensor
Instrument used to measure the photosynthetically active radiation spectral range of solar radiation. It is assumed to have a spectral response of 400-700nm. It could have any type of collector (flat plate cosine collector, spherical or hemispherical).
Trimble 4000DS Global Positioning System receiver
The Trimble 4000DS Differential Surveyor is similar to the 4000RS (a Maxwell-based receiver that is oriented toward precision positioning applications. It is intended for use as a DGPS base station, generating RTCM-104 corrections). The 4000Ds can apply RTCM-104 corrections to the satellite data it receives in order to generate accurate position fixes in real time.
RRS James Clark Ross AMT6 (JR32) Meteorological Instrumentation
The instrumentation has been collated from various sources as historic notation of instrumentation was not well maintained. Care may be required if making assumptions based on the instruments used.
The following instruments used for meteorological measurements:
Instrument Name | Model | Serial Number | Parameter(s) |
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Kipp & Zonen CM10 Pyranometer | CM10 | N/A | Solar Irradiance |
Vector Instruments air temperature sensor | Unknown | N/A | Temperature of the atmosphere |
Vector Instruments cup anemometer | Unknown | N/A | Relative Wind Speed |
Vector Instruments wind vane | Unknown | N/A | Relative Wind Direction |
Trimble 4000DS Global Positioning System Receiver | 4000DS | N/A | Latitude and Longitude |
Didcot DRP-1 PAR Sensor | DRP-1 | N/A | Photosynthetically Active Radiation |
Cruise Name | JR19980514 (AMT6, JR32) |
Departure Date | 1998-05-14 |
Arrival Date | 1998-06-16 |
Principal Scientist(s) | James Aiken (Plymouth Marine Laboratory) |
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 |
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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 |
National Oceanography Centre
Joseph Proudman Building
6 Brownlow Street
Liverpool
L3 5DA
United Kingdom
National Oceanography Centre
European Way
Southampton
SO14 3ZH
United Kingdom