Metadata Report for BODC Series Reference Number 1044338


Metadata Summary

Data Description

Data Category Surface temp/sal
Instrument Type
NameCategories
SeaTech transmissometer  transmissometers
WETLabs WETStar fluorometer  fluorometers
Falmouth Scientific Instruments OEM conductivity-temperature sensor  water temperature sensor; salinity sensor
Instrument Mounting research vessel
Originating Country United Kingdom
Originator Dr Sheldon Bacon
Originating Organization National Oceanography Centre, Southampton
Processing Status banked
Project(s) Rapid Climate Change Programme
RAPID-Bacon
 

Data Identifiers

Originator's Identifier D298_PRODQXF_SURF
BODC Series Reference 1044338
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2005-08-25 02:07
End Time (yyyy-mm-dd hh:mm) 2005-09-21 00:01
Nominal Cycle Interval 120.0 seconds
 

Spatial Co-ordinates

Start Latitude 55.76650 N ( 55° 46.0' N )
End Latitude 57.86390 N ( 57° 51.8' N )
Start Longitude 4.86310 W ( 4° 51.8' W )
End Longitude 36.23510 W ( 36° 14.1' W )
Positional Uncertainty 0.0 to 0.01 n.miles
Minimum Sensor Depth 5.0 m
Maximum Sensor Depth 5.0 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
FVLTWS01 1 Volts WsVolt Instrument output (voltage) by linear-response chlorophyll fluorometer
PSALSG01 1 Dimensionless P_sal_TSG_calib Practical salinity of the water body by thermosalinograph and computation using UNESCO 1983 algorithm and calibration against independent measurements
TEMPHG01 1 Degrees Celsius CalTSGHullTmp Temperature of the water body by thermosalinograph hull sensor and verification against independent measurements
TVLTDR01 1 Volts TrVoltRed25 Instrument output (voltage) by 25cm path length red light transmissometer
 

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

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

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 S cal = 0.5771 + (0.9795 x S TSG ) where S TSG is the uncalibrated data and S cal 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

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:

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