Metadata Report for BODC Series Reference Number 1222911


Metadata Summary

Data Description

Data Category Meteorology -unspecified
Instrument Type
NameCategories
Kipp and Zonen CM10 pyranometer  radiometers
Vector Instruments air temperature sensor  meteorological packages
Vector Instruments cup anemometer  anemometers
Vector Instruments wind vane  anemometers
Trimble 4000DS Global Positioning System receiver  Differential Global Positioning System receivers
Didcot DRP-1 PAR sensor  radiometers
Instrument Mounting research vessel
Originating Country United Kingdom
Originator Prof Jim Aiken
Originating Organization Plymouth Marine Laboratory
Processing Status banked
Project(s) Atlantic Meridional Transect (AMT)
 

Data Identifiers

Originator's Identifier AMT6_MET
BODC Series Reference 1222911
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 1998-05-15 12:00
End Time (yyyy-mm-dd hh:mm) 1998-06-16 08:41
Nominal Cycle Interval 30.0 seconds
 

Spatial Co-ordinates

Start Latitude 33.63250 S ( 33° 37.9' S )
End Latitude 53.58640 N ( 53° 35.2' N )
Start Longitude 18.01410 E ( 18° 0.8' E )
End Longitude 0.02860 E ( 0° 1.7' E )
Positional Uncertainty 0.0 to 0.01 n.miles
Minimum Sensor Depth -13.5 m
Maximum Sensor Depth -13.5 m
Minimum Sensor Height -
Maximum Sensor Height -
Sea Floor Depth -
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 -
 

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)
ALATGP01 1 Degrees Lat_GPS Latitude north (WGS84) by unspecified GPS system
ALONGP01 1 Degrees Lon_GPS Longitude east (WGS84) by unspecified GPS system
CDTASS01 1 Degrees Celsius AirTemp Temperature of the atmosphere by dry bulb thermometer
CSLRZZ01 1 Watts per square metre SolarRad Downwelling vector irradiance as energy (solar wavelengths) in the atmosphere by pyranometer
DWIRRXSD 1 Watts per square metre SurfVPAR Downwelling vector irradiance as energy (PAR wavelengths) in the atmosphere by cosine-collector radiometer
ERWDSS01 1 Degrees RelWindDirFrom_IS Wind direction (relative to moving platform) in the atmosphere by in-situ anemometer
ERWSSS01 1 Metres per second RelWindSpd Wind speed (relative to moving platform) in the atmosphere by in-situ anemometer
EWDASS01 1 Degrees True WindDirFrom Wind from direction in the atmosphere by in-situ anemometer
EWSKSS01 1 Knots (nautical miles per hour) WindSpd Wind speed in the atmosphere by in-situ anemometer
 

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

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/m 2 ) 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 (Al 2 O 3 ) 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.
Spectral range 310 - 2800 nm (50% points)
340 - 2200 nm (95% points)
Irradiance 0 - 1400 W/m 2 (max. 4000 W/m 2 )
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:

RRS James Clark Ross AMT6 (JR32) Meteorological Data Processing Procedures

Originator's Data Processing

Raw data were logged as ADC counts on the ship's computers. They were converted into engineering units using initial manufacturers' calibrations.

The data were submitted to BODC in RVS internal format for post-cruise processing and data banking.

BODC Data Processing

Reformatting

Underway data files were merged into a single binary merge file using time as the primary linking key. The time span of the file was from 15/05/1998 12:00:30 to 16/06/1998 08:41:30, with a sampling interval of 30 seconds.

Screening

Each data channel was inspected on a graphics workstation and any spikes or periods of dubious data were flagged. The power of the workstation software was used to carry out comparative screening checks between channels by overlaying data channels. A map of the cruise track was simultaneously displayed in order to take account of the oceanographic context.

Data processing, correction and calibration

Relative wind speed and direction were logged from the meteorological package during the cruise. The ship's speed and heading channels were used with the relative wind data to produce absolute wind speed and direction.


Project Information

The Atlantic Meridional Transect (AMT) - Phase 1 (1995-2000)

Who was involved in the project?

The Atlantic Meridional Transect (AMT) programme was designed by and implemented as a collaboration between Plymouth Marine Laboratory (PML) and Southampton Oceanography Centre (SOC). The programme was hosted by Plymouth Marine Laboratory and involved additional researchers from UK and international universities throughout its duration.

What was the project about?

When AMT began in 1995 the programme provided a platform for international scientific collaboration, including the calibration and validation of SeaWiFs measurements and products. The programme provided an exceptional opportunity for nationally and internationally driven collaborative research and provided a platform for excellent multi-disciplinary oceanographic research. As an in situ observation system, the data collected by the AMT consortium informed on changes in biodiversity and function of the Atlantic ecosystem during this period of rapid change to our climate and biosphere.

The scientific aims were to assess:

When was the project active?

The first phase of the AMT programme ran from 1995 to 2000 and consisted of a total of 12 cruises. A second phase of funding allowed the project to continue for the period 2002 to 2006 with a further 6 cruises.

Brief summary of the project fieldwork/data

The AMT programme undertook biological, chemical and physical oceanographic research during the annual return passage of the RRS James Clark Ross between the UK and the Falkland Islands or the RRS Discovery between the UK and Cape Town, a distance of up to 13,500 km. This transect crossed a range of ecosystems from sub-polar to tropical and from euphotic shelf seas and upwelling systems to oligotrophic mid-ocean gyres. The transect route was covered north-south in September/October and south-north in April/May of each year.

The measurements of hydrographic and bio-optical properties, plankton community structure and primary production completed on the first 12 transects (1995-2000) represent the most coherent set of repeated biogeochemical observations over ocean basin scales. This unique dataset has led to several important discoveries concerning the identification of oceanic provinces, validation of ocean colour algorithms, distributions of picoplankton, identifying new regional sinks of pCO2 and variability in rates of primary production and respiration.

Who funded the project?

The programme was funded by the Natural Environment Research Council (NERC) and further support was received from the National Aeronautics and Space Administration (NASA) with equipment and funding from the Sea-viewing Wild Field-of-view Sensor (SeaWiFS) project.


Data Activity or Cruise Information

Cruise

Instrument Name Model Serial Number Parameter(s)
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
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