Metadata Report for BODC Series Reference Number 1051095

• 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 D277 Underway Meteorology Data Quality Report

Solar Radiation (TIR)

Data from the port sensor are of good quality with no flagging necessary. The starboard sensor proved more problematic with areas of noisy data mostly occuring during the night throughout the cruise. A fault in this sensor was reported as the cause of the noise. The decision was made not to merge port and starboard sensor data due to this fault.

Relative humidity

There are frequent data spikes throughout the channel. These have been flagged suspect.

Wind speed and direction

There is still a residual of ship's heading and velocity apparent in the absolute wind speed and direction channels (especially the latter). Suspect data, where values were deemed to have been influenced by changes in the ship's heading/velocity, have been flagged accordingly.

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

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

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 D277 Underway Meteorology Instrumentation

Meterological data were collected with a Vaisala QLI50 sensor collector (s/n: R381005) using the following suite of instruments;

RAPID Cruise D277 Underway Meteorology Processing

Originator's Processing

Meterological measurements were sent along with thermosalinograph (TSG) system measurements to the ship's central logging system. Onboard processing was carried out on a daily basis and involved running a sequence of executable programs. The initial stage transferred the underway data from raw RVS format to PSTAR format. Subsequent processing included the merging of different data streams, with an additional executable being run to determine the true wind speed and direction, taking account of the ship's motion and velocity. Finally, Julian Day time variable data were calculated and the resulting data examined by plotting on a daily and weekly basis.

The data were supplied to BODC as 2 minute averages in PSTAR format.

BODC processing

The data files received were transferred from PSTAR format into BODC's in-house NetCDF format to allow use of the in-house visualisation tool (EDSERPLO). The transfer process also includes the flagging of data which fall outside of the range of acceptable values for each parameter. Ship's navigation data were merged with underway sea surface hydrography using time as the primary linking key.

Each data channel was visually inspected and any spikes or periods of dubious data flagged as suspect. The capabilities of the screening software allows all possible comparative screening checks between channels.

Photosynthetically Active Radiation (PAR)

It was discovered at BODC that the port 'PAR' sensor was in fact a solarimeter, which measures radiation of a different wavelength range to a true PAR sensor (and has been excluded from this series). This meant that port and starboard sensor data could not be merged due to the different sensor types used. In addition, the starboard sensor output remains uncalibrated as sensor serial number was unknown.

Solar Radiation (TIR)

Port and starboard sensor data were not merged as the record returned from the starboard TIR sensor was somewhat noisy, especially at night.

Wind speed and direction

BODC received logged values of true wind speed and direction, with corrections applied to account for the ship's heading and velocity.

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.

Monitoring the Meridional Overturning Circulation at 26.5N (RAPIDMOC)

Scientific Rationale

There is a northward transport of heat throughout the Atlantic, reaching a maximum of 1.3PW (25% of the global heat flux) around 24.5°N. The heat transport is a balance of the northward flux of a warm Gulf Stream, and a southward flux of cooler thermocline and cold North Atlantic Deep Water that is known as the meridional overturning circulation (MOC). As a consequence of the MOC northwest Europe enjoys a mild climate for its latitude: however abrupt rearrangement of the Atlantic Circulation has been shown in climate models and in palaeoclimate records to be responsible for a cooling of European climate of between 5-10°C. A principal objective of the RAPID programme is the development of a pre-operational prototype system that will continuously observe the strength and structure of the MOC. An initiative has been formed to fulfill this objective and consists of three interlinked projects:

• A mooring array spanning the Atlantic at 26.5°N to measure the southward branch of the MOC (Hirschi et al., 2003 and Baehr et al., 2004).
• Additional moorings deployed in the western boundary along 26.5°N (by Prof. Bill Johns, University of Miami) to resolve transport in the Deep Western Boundary Current (Bryden et al., 2005). These moorings allow surface-to-bottom density profiles along the western boundary, Mid-Atlantic Ridge, and eastern boundary to be observed. As a result, the transatlantic pressure gradient can be continuously measured.
• Monitoring of the northward branch of the MOC using submarine telephone cables in the Florida Straits (Baringer et al., 2001) led by Dr Molly Baringer (NOAA/AOML/PHOD).

The entire monitoring array system created by the three projects will be recovered and redeployed annually until 2008 under RAPID funding. From 2008 until 2014 the array will continue to be serviced annually under RAPID-WATCH funding.

The array will be focussed on three regions, the Eastern Boundary (EB), the Mid Atlantic Ridge (MAR) and the Western Boundary (WB). The geographical extent of these regions are as follows:

• Eastern Boundary (EB) array defined as a box with the south-east corner at 23.5°N, 25.5°W and the north-west corner at 29.0°N, 12.0°W
• Mid Atlantic Ridge (MAR) array defined as a box with the south-east corner at 23.0°N, 52.1°W and the north-west corner at 26.5°N, 40.0°W
• Western Boundary (WB) array defined as a box with the south-east corner at 26.0°N, 77.5°W and the north-west corner at 27.5°N, 69.5°W

References

Baehr, J., Hirschi, J., Beismann, J.O. and Marotzke, J. (2004) Monitoring the meridional overturning circulation in the North Atlantic: A model-based array design study. Journal of Marine Research, Volume 62, No 3, pp 283-312.

Baringer, M.O'N. and Larsen, J.C. (2001) Sixteen years of Florida Current transport at 27N Geophysical Research Letters, Volume 28, No 16, pp3179-3182

Bryden, H.L., Johns, W.E. and Saunders, P.M. (2005) Deep Western Boundary Current East of Abaco: Mean structure and transport. Journal of Marine Research, Volume 63, No 1, pp 35-57.

Hirschi, J., Baehr, J., Marotzke J., Stark J., Cunningham S.A. and Beismann J.O. (2003) A monitoring design for the Atlantic meridional overturning circulation. Geophysical Research Letters, Volume 30, No 7, article number 1413 (DOI 10.1029/2002GL016776)

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: