Metadata Report for BODC Series Reference Number 1044338
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
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Time Co-ordinates(UT) |
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Parameters |
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Problem Reports
No Problem Report Found in the Database
RAPID Cruise D298 Underway Surface Hydrography Data Quality Report
It would appear that the flow through pump was not switched on or funtioning until 10:23 on 27 August 2005. All salinity, fluorescence and transmissometer data logged up to this time, therefore, have been flagged suspect.
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
Falmouth Scientific Inc. OEM CT sensor
The OEM CT sensor is designed to provide high accuracy conductivity and temperature measurements in a package that can be readily integrated into user systems. The CT sensor relies on an inductively coupled conductivity sensor, with a large inside diameter that eliminates the need for pumps. A high grade Platinum Resistance Thermometer is used to measure temperature.
Sensor specifications are given in the table below. Since 2009 this instrument has been manufactured by Teledyne RD Instruments as a Citadel CT-EK Sensor. More information about the instrument can be found on the Teledyne Citadel specification sheet.
Sensor Specifications
| Instrument Parameter | Small CT Cell Conductivity | Large CT Cell Conductivity | Temperature | |
|---|---|---|---|---|
| Range | 0 to 70 mS cm-1 | 0 to 70 mS cm-1 | -2 to 35 degrees C | |
| Accuracy | ±0.020 mS cm-1 | ±0.010 mS cm-1 | ±0.050 degrees C | |
| Stability | ±0.005 mS cm-1 mo-1 | ±0.003 mS cm-1 | ±0.005 degrees C mo-1 | |
| Response | 20 cm @ 1 m s-1 | 15 cm @ 1 m s-1 | 20 seconds internal, 1 second external |
| Power Input | 50 mW @ 6 VDC, voltage range 6 - 14 VDC |
|---|---|
| Logic | 2 0 - 5 VDC control lines |
| Output Impedance | 500 ohms |
WET Labs WETStar Fluorometers
WET Labs WETStar fluorometers are miniature flow-through fluorometers, designed to measure relative concentrations of chlorophyll, CDOM, uranine, rhodamineWT dye, or phycoerythrin pigment in a sample of water. The sample is pumped through a quartz tube, and excited by a light source tuned to the fluorescence characteristics of the object substance. A photodiode detector measures the portion of the excitation energy that is emitted as fluorescence.
Specifications
By model:
| Chlorophyll WETStar | CDOM WETStar | Uranine WETStar | Rhodamine WETStar | Phycoerythrin WETStar | |
|---|---|---|---|---|---|
| Excitation wavelength | 460 nm | 370 nm | 485 nm | 470 nm | 525 nm |
| Emission wavelength | 695 nm | 460 nm | 530 nm | 590 nm | 575 nm |
| Sensitivity | 0.03 µg l-1 | 0.100 ppb QSD | 1 µg l-1 | - | - |
| Range | 0.03-75 µg l-1 | 0-100 ppb; 0-250 ppb | 0-4000 µg l-1 | - | - |
All models:
| Temperature range | 0-30°C |
|---|---|
| Depth rating | 600 m |
| Response time | 0.17 s analogue; 0.125 s digital |
| Output | 0-5 VDC analogue; 0-4095 counts digital |
Further details can be found in the manufacturer's specification sheet, and in the instrument manual.
SeaTech Transmissometer
Introduction
The transmissometer is designed to accurately measure the the amount of light transmitted by a modulated Light Emitting Diode (LED) through a fixed-length in-situ water column to a synchronous detector.
Specifications
- Water path length: 5 cm (for use in turbid waters) to 1 m (for use in clear ocean waters).
- Beam diameter: 15 mm
- Transmitted beam collimation: <3 milliradians
- Receiver acceptance angle (in water): <18 milliradians
- Light source wavelength: usually (but not exclusively) 660 nm (red light)
Notes
The instrument can be interfaced to Aanderaa RCM7 current meters. This is achieved by fitting the transmissometer in a slot cut into a customized RCM4-type vane.
A red LED (660 nm) is used for general applications looking at water column sediment load. However, green or blue LEDs can be fitted for specilised optics applications. The light source used is identified by the BODC parameter code.
Further details can be found in the manufacturer's Manual.
RAPID Cruise D298 Underway Surface Hydrography Instrumentation
Seawater was continually pumped from the hull of the ship at an approximate depth of 5m through the various underway sensors (known as the ship's non-toxic supply). The details of these sensors are shown in the table below.
| Sensor | Serial number | Last calibration date |
|---|---|---|
| FSI OCM housing conductivity sensor | 1376 | Original manufacturer's calibration |
| FSI OTM housing temperature sensor | 1370 | Calibration stored internally |
| FSI OTM remote temperature sensor | 1360 | Calibration stored internally |
| Seatech transmissometer | 112R | Unknown |
| Wetlabs fluorometer | 246 | 5/12/2004 |
An outlet from the non toxic supply, situated in the ship's wet laboratory, was used to collect the calibration samples for the underway sensors.
RAPID Cruise D298 Underway Meteorology, Surface Hydrography and Navigation Series
Cruise Details
| Dates | 23 August - 25 September 2005 |
|---|---|
| Principal Scientific Officer | Dr Sheldon Bacon (NOC,S) |
| Cruise Report | Bacon, S. and et al., 2006. RRS Discovery Cruise 298, 23 Aug-25 Sep 2005. Cape Farewell and Eirik Ridge (CFER-1). Southampton, UK, National Oceanography Centre Southampton, 113pp. (National Oceanography Centre Southampton Cruise Report, 10). |
D298 was conducted in the vicinty of Cape Farewell, southern Greenland, during early autumn 2005. The main priority of the cruise was to complete a number of mooring operations, but this work was combined with additional hydrographic survey work, sediment coring and sub-bottom profiling.
Data Processing Procedures
Underway sea surface hydrography, meteorology and ship's navigation data are merged into common files using time (UTC) as the primary linking key. Any additional data calibrations are applied as appropriate and are discussed in the individual instrument sections.
Data were transferred to BODC's in-house NetCDF format, QXF, through the BODC Underway Data System (BUDS). During transfer data were time averaged to 120 second intervals. The transfer process also includes the flagging of data which fall outside of the range of acceptable values for each parameter.
Each data channel is visually inspected on a graphics workstation and any spikes or periods of dubious data are flagged as suspect. The capabilities of the workstation screening software allows all possible comparative screening checks between channels. The system also has the facililty 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 D298 Underway Surface Hydrography Processing
Originator's processing
Conductivity, salinity, sea surface temperature, fluorescence and transmissivity were logged from water gathered from the non-toxic pumped sea water supply from the hull of the ship at a depth of approximately 5 metres. Data were transferred from the raw RVS format to PSTAR format using unix command scripts and compiled into 2 minute averages.
BODC processing
Salinity
Salinity data were calibrated at BODC, with discrete TSG samples collected during the cruise, using the linear correction provided by the data originator.
The linear correction applied was Scal = 0.5771 + (0.9795 x STSG) where STSG is the uncalibrated data and Scal is the calibrated data.
Temperature
The hull temperature data were calibrated at BODC using near surface CTD temperature data. Note, the CTD measurements have not been verified against an independent source. The offset (CTD temperature - underway temperature) was examined to see if it varied with time or temperature. 16 outliers, with high standard deviations, were identified and discarded. No significant correlation was established between offset and CTD temperature or time. Therefore a correction was applied to the temperature of the form;
Calibrated underway temperature = underway temperature - 0.036523
Transmittance
Transmittance data were logged as raw voltages, and no calibrations were applied by BODC
Fluorescence
Fluorescence data were logged as raw voltages, and no calibrations were applied by BODC.
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.
RAPID - Cape Farewell and Eirik Ridge: Interannual to Millennial Thermohaline Circulation Variability
This project was funded under the NERC Rapid Climate Change Programme, grant number NER/T/S/2002/00453. Dr. Sheldon Bacon (Southampton Oceanography Centre) was the Principal Investigator, with co-Investigators from the University of Southampton, Prof. D. A. Stow and Dr. E. J. Rohling. The project started in December 2003 and ended in November 2008.
The project used a combination of hydrography and palaeoceanography measurements to determine the spectrum of variability of the Deep Western Boundary Current, on timescales from days to millennia. The project focused on deglacial to Holocene variability; in particular, seeking to characterise the onset and endings of three cold periods: the Younger Dryas (YD; 12.5-11.5 ka BP), the ~8.2 ka event, and the Little Ice Age (LIA; 16th-19th century AD).
The objectives of the project included:
- Defining the THC response to Holocene climate variability by a highly resolved investigation of palaeoceanographic/climate proxies in sediment cores
- Developing high-resolution sediment proxies for bottom current speed
- Absolute calibration of sediment proxies for bottom current speed
- Defining the relationship between drift construction and the bottom current regime
- Improved definition of present-day ocean circulation and climate
Most of the fieldwork was carried out on 2 cruises in the Cape Farewell and Irminger Sea vicinity:
| Cruise | Start | End | Comments |
|---|---|---|---|
| D298 | 2008-08-23 | 2005-09-05 | Work included mooring deployments, sediment coring, sampling for isotopes and CTD casts |
| D309-310 | 2006-08-18 | 2006-09-05 | Work included mooring turn-arounds and CTD casts. |
Data Activity or Cruise Information
Cruise
| Cruise Name | D298 |
| Departure Date | 2005-08-23 |
| Arrival Date | 2005-09-25 |
| Principal Scientist(s) | Sheldon Bacon (National Oceanography Centre, Southampton) |
| 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 |
|---|---|
| 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 |
| B | nominal value |
| Q | value below limit of quantification |
