Metadata Report for BODC Series Reference Number 788327

• 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

Problem Reports

No Problem Report Found in the Database

RAPID Cruise CD160 Underway Meteorology - Data Quality Report

It should be noted that data logging was suspended between 13/08/2004 and 18/08/2004 whilst the ship was in port for engine repairs.

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

Vaisala Analog Barometers Models PTB100 (A), (B) and PTB101 (B), (C)

The PTB 100 series analog barometers are designed both for accurate barometric measurements at room temperature and for general environmental pressure monitoring over a wide temperature range. The long-term stability of the barometer minimizes the need for field adjustment in many applications.

Physical Specifications

The barometers use the BAROCAP^* silicon capacitive absolute pressure sensor developed by Vaisala for barometric pressure measurements. The BAROCAP^* sensor combines the elasticity characteristics and mechanical stability of a single-crystal silicon with the proven capacitive detection principle.

Sensor Specifications

^* BAROCAP is a registered trademark of Vaisala

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.

Vaisala WA15 Wind Set

The WAA151 combines a WAA151 anemometer and a WAV151 wind vane, to measure wind speed and direction.

WAA151 Anemometer

The anemometer has three lightweight conical cups in the cup wheel. A wind-rotated chopper disc, attached to the cup wheel's shaft, cuts an infrared light beam 14 times per revolution, generating a pulse output from a phototransistor. The output rate can be regarded as directly proportional to the wind speed. However, for the best accuracy, a transfer function is used to compensate starting inertia and slight over-speeding:

U_f = 0.328 + 0.101 x R, where U_f = wind speed and R = output pulse rate

A thermostatically controlled heating element in the shaft tunnel prevents the bearings from freezing in cold environments.

WAV151 Wind Vane

The WAV151 is a counter-balanced optelectronic wind vane. Infrared LEDs and phototransistors are mounted in six orbits around a 6 bit Gray coded disc. Turned by the vane, the disc determines the code received by the phototransistors.

Specifications

Further details can be found in the manufacturer's specification document.

Didcot Cosine Photosynthetically Available Radiation (PAR) sensors

The silicon cell, blue glass filter and diffuser are bond together using optically clear adhesive, the complete assembly is mounted into the black anodised body and sealed using the same adhesive. The body has a raised rim to provide to provide low angle cosine correction and holes within the rim to provide drainage for surface water which would otherwise affect the instrument's accuracy. Model DRP-5 has an integral clamp to mount on a vertical mast tube, model DRP-5B has round base with three leveling screws and is intended to stand on a flat surface and model DRP-4 has a built in integrator to record total PAR received over a period of time.

Technical Information

RAPID Cruise CD160 Meteorology Instrumentation Details

RAPID Cruise CD160 Sea Surface Hydrography, Meteorology and Navigation

Cruise details

A full copy of the Metadata report can be found here: CD160

Data Aquisition and Onboard Processing

Meterological data were collected with a Vaisala QLI50 sensor collector (s/n: R381006) and sent, along with TSG system measurements, to the ship's central logging system. ASCII files were generated for each 24 hour period of the cruise and loaded into Matlab for further processing. Large spikes in conductivity and temperature were removed, and surface salinity calculated from conductivity and housing temperature data. An additional routine was run to determine the true wind speed and direction, taking account of the ship's motion. The data were subsequently averaged (2 minute resolution) with latitude and longitude interpolated to the SurfMet timestamps. Finally, one file was produced, containing the averaged data for the whole cruise.

BODC underway data processing

All underway sea surface hydrography, meteorology and ship's navigation data were merged into a common QXF file using time (GMT) as the primary linking key. Navigation was checked for improbable speeds and gaps, wind speed and direction were corrected for ship's motion and heading and any additional data calibrations were applied as appropriate.

The QXF file then underwent a further step. This involved using Matlab transfer 378 to split the underway QXF file into three separate QXF files. One contained data for sea surface hydrography, one for meteorological data and the final QXF file held the navigation data.

Each data channel was visually inspected on a graphics workstation and any spikes or periods of dubious data were flagged as suspect. The capabilities of the workstation screening software allows all possible comparative screening checks between channels (e.g. to ensure corrected wind data have not been influenced by changes in ship's heading). The system also has the facility of simultaneously displaying the data and the ship's position on a map to enable data screening to take oceanographic climatology into account.

RAPID Cruise CD160 Underway Meteorology Series Processing

• Photosynthetically Active Radiation (PAR)

  Manufacturer's calibration equations were rearranged and used to convert the PAR sensor data (port and starboard) from volts to watts per squared metre. The equations, taken from the sensor calibration sheets, were as follows:

  1) PAR (port): 14.81 mV = 1 kWm^-2

  2) PAR (starboard): 13.74 mV = 1 kWm^-2

  Port and starboard data were subsequently merged into one channel. This process selects the highest value from each sensor, for each timestamp, and discards the lower value, where sensor shading may have occurred. The merged PAR data were screened alongside merged TIR for comparison.

  Although the merged channel is all that is provided with this data, both port and starboard channels are available on request.

• Solar Radiation (TIR)

  Manufacturer's calibration equations were rearranged and used to convert the TIR sensor data (port and starboard) from volts to watts per squared metre. The equations, taken from the sensor calibration sheets, were as follows:

  3) TIR (port): 10.26 µV = 1 kWm^-2

  4) TIR (starboard): 9.78 µV = 1 kWm^-2

  Port and starboard data were subsequently merged into one channel. This process selects the highest value from each sensor, for each timestamp, and discards the lower value, where sensor shading may have occurred. The merged TIR data were screened alongside merged PAR for comparison.

  Although the merged channel is all that is provided with this data, both port and starboard channels are available on request.

• Atmospheric pressure

  The original instrument (s/n S3440009) recorded data between 04/08/2008 and 14/08/2004, but subsequently failed when the ship returned to port for repairs. The replacement Vaisala PTB 100A sensor (s/n S3440012) was used for the period 18/08/2004 to 24/08/2004.

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.

Data Activity or Cruise Information

Cruise

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:

SeaDataNet Quality Control Flags

The following single character qualifying flags may be associated with one or more individual parameters with a data cycle: