Metadata Report for BODC Series Reference Number 1749271


Metadata Summary

Data Description

Data Category Surface temp/sal
Instrument Type
NameCategories
WETLabs WETStar fluorometer  fluorometers
WETLabs C-Star transmissometer  transmissometers
Sea-Bird SBE 45 MicroTSG thermosalinograph  thermosalinographs; water temperature sensor; salinity sensor
Sea-Bird SBE 38 thermometer  water temperature sensor
Instrument Mounting research vessel
Originating Country United Kingdom
Originator Mr Martin Bridger
Originating Organization National Marine Facilities Sea Systems
Processing Status banked
Project(s) UKOARP_ThemeB
 

Data Identifiers

Originator's Identifier D366_PRODQXF_SURF
BODC Series Reference 1749271
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2011-06-06 08:08
End Time (yyyy-mm-dd hh:mm) 2011-07-09 12:55
Nominal Cycle Interval 60.0 seconds
 

Spatial Co-ordinates

Southernmost Latitude 45.36083 N ( 45° 21.6' N )
Northernmost Latitude 60.00283 N ( 60° 0.2' N )
Westernmost Longitude 12.02200 W ( 12° 1.3' W )
Easternmost Longitude 10.01383 E ( 10° 0.8' E )
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
ATTNDR01 1 per metre Attn_Red_25cm Attenuation (red light wavelength) per unit length of the water body by 25cm path length red light transmissometer
CPHLUMTF 1 Milligrams per cubic metre chl-a_water_NTTFfluor_manufctrcal Concentration of chlorophyll-a {chl-a CAS 479-61-8} per unit volume of the water body [particulate >unknown phase] by through-flow fluorometer plumbed into non-toxic supply and manufacturer's calibration applied
FVLTWS01 1 Volts WsVolt Instrument output (voltage) by linear-response chlorophyll fluorometer
POPTDR01 1 Percent Trans_Red_25cm Transmittance (red light wavelength) per 25cm of the water body by 25cm path length red light transmissometer
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
 

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

UK Ocean Acidification RRS Discovery Cruise D366 Underway Surface Hydrography Data Quality Report

Salinity, conductivity and temperature

No extensive flagging was required. The values fit within the range for the regions the cruise track passed through, for the time of year of the cruise.

Attenuance and transmittance

The transmissometer voltage declines in the second half of the cruise, then jumps back up before declining again. This coincides with the time around the Skaggerak with the low salinity waters. The sudden jumps in the transmissometer and fluorometer time series are due to the cleaning of the instrument on station according to the NMF report. The data have been flagged during periods when the transmissometer and Fluorometer were cleaned. This occured at the following times: 09/06/2014 1337-1347; 15/06/2014 0900-0910 and 30/06/2014 0834-0844. Intermittent flags were applied to obvious spikes in the transmissometer voltage channel. Where the transmittance voltage was 0 (close to the dark voltage output) which occurred during cleaning of the sensor, these were flagged Null instead of suspect in order to apply the manufacturers calibration correctly.

Fluorescence

The voltage was flagged sparingly as it shows natural variation. Cleaning of the instrument occurred at the same times as for the transmissometer, and data were flagged during these periods.


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

SeaBird Digital Oceanographic Thermometer SBE38

The SBE38 is an ultra-stable thermistor that can be integrated as a remote temperature sensor with an SBE21 Thermosalinograph or an SBE 45 Micro TSG, or as a secondary temperature sensor with an SBE 16 plus, 16plus-IM, 16plus V2, 16plus-IM V2 or 19plus V2 SEACAT CTD.

Temperature is determined by applying an AC excitation to reference resistances and an ultra-stable aged thermistor. The reference resistor is a hermetically sealed VISHAY. AC excitation and ratiometric comparison using a common processing channel removes measurement errors due to parasitic thermocouples, offset voltages, leakage currents and gain errors.

The SBE38 can operate in polled sampling, where it takes one sample and transmits the data, or in continuous sampling.

Specifications

Depth rating up to 10500 m
Temperature range -5 to 35°C
Initial accuracy ± 0.001°C
Resolution 0.00025°C
Stability 0.001°C in 6 months
Response time 500 ms
Self-heating error < 200 µK

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

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 .

WETLabs C-Star transmissometer

This instrument is designed to measure beam transmittance by submersion or with an optional flow tube for pumped applications. It can be used in profiles, moorings or as part of an underway system.

Two models are available, a 25 cm pathlength, which can be built in aluminum or co-polymer, and a 10 cm pathlength with a plastic housing. Both have an analog output, but a digital model is also available.

This instrument has been updated to provide a high resolution RS232 data output, while maintaining the same design and characteristics.

Specifications

Pathlength 10 or 25 cm
Wavelength 370, 470, 530 or 660 nm
Bandwidth

~ 20 nm for wavelengths of 470, 530 and 660 nm

~ 10 to 12 nm for a wavelength of 370 nm

Temperature error 0.02 % full scale °C -1
Temperature range 0 to 30°C
Rated depth

600 m (plastic housing)

6000 m (aluminum housing)

Further details are available in the manufacturer's specification sheet or user guide .

SeaBird MicroTSG Thermosalinograph SBE 45

The SBE45 MicroTSG is an externally powered instrument designed for shipboard measurement of temperature and conductivity of pumped near-surface water samples. The instrument can also compute salinity and sound velocity internally.

The MicroTSG comprises a platinum-electrode glass conductivity cell and a stable, pressure-protected thermistor temperature sensor. It also contains an RS-232 port for appending the output of a remote temperature sensor, allowing for direct measurement of sea surface temperature.

The instrument can operate in Polled, Autonomous and Serial Line Sync sampling modes:

Specifications

  Conductivity Temperature Salinity
Range 0 to 7 Sm -1 -5 to 35°C  
Initial accuracy 0.0003 Sm -1 0.002°C 0.005 (typical)
Resolution 0.00001 Sm -1 0.0001°C 0.0002 (typical)
Typical stability (per month) 0.0003 Sm -1 0.0002°C 0.003 (typical)

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

UK Ocean Acidification RRS Discovery Cruise D366 Underway Surface Hydrography Instrumentation

The instruments used to collect the surface hydrography datasets are displayed in the table below.

Sensor Serial number Calibration date
Sea-Bird SBE38 0490 04/10/2010
Sea-Bird SBE45 0230 16/07/2010
Seatech C-star CST-1132PR 04/06/2010
Wetlabs WetStar WS3S-248 15/12/2010

UK Ocean Acidification RRS Discovery Cruise D366 Underway Surface Hydrography Data Processing Document

Originator's Data Processing

During the cruise there was a dual logging system in place on the RRS Discovery. Data from the various instruments were logged to the RVS Level-C system and also as NetCDF (binary) through the Ifremer Techsas data logging system.

Files delivered to BODC

Filename Data type Start Calendar Day Start Time Finish Calendar Day Finish Time Interval
seabird RVS Level-C raw 2011-06-06 08:08:48 2011-07-09 12:55:52 1 sec
surfmet RVS Level-C raw 2011-06-06 08:08:47 2011-07-09 12:55:53 1 sec

BODC Data Processing

Reformatting

The RVS files were transferred into internal BODC format by merging the files into a single binary file using time as the primary linking key. The time span of the file was from 06/06/2011 08:08:50 to 09/07/2011 12:55:50, with a sampling interval of 60 seconds.

The surface hydrography data were transferred to BODC format from the surfmet and seabird data files.

The originator's variables were mapped to appropriate BODC parameter codes as follows:

surfmet

Channels Description Units BODC Parameter Code Units Conversion Factor
temp_h TSG housing temperature - not for transfer - loaded from seabird file with salinity - -
temp_m Remote temperature at non-toxic inlet - not for transfer - loaded from seabird file with salinity - -
cond TSG conductivity - not for transfer - loaded from seabird file with salinity - -
fluo Raw fluorometer voltage V FVLTWS01 V *1
trans Raw transmissometer voltage V TVLTDR01 - channel not transferred V *1

seabird

Channels Description Units BODC Parameter Code Units Conversion Factor
temp_h TSG housing temperature Degrees Celsius TMESSG01 - channel not transferred Degrees Celsius *1
cond TSG conductivity S m -1 CNDCSG01 - channel not transferred S m -1 *1
salin Salinity PSU PSALSU01 - uncalibrated dimensionless *1
sndspeed Velocity of sound in water m s -1 SVELSG01 - channel not transferred m s -1 *1
temp_r Remote temperature at non-toxic inlet Degrees Celsius TEMPHU01 - uncalibrated Degrees Celsius *1

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.

Manufacturer's Calibratons

Transmissometer

The table below shows the Manufactuers calibration applied to the transmissometer voltage channel.

Channel Manufactuers Calibration equation Coefficient Values
Transmittance (POPTDR01) Light transmission (%) = 100 x (TVLTDR01 - Vdark) / (Vref - Vdark) Vdark = 0.059 V, Vref = 4.685 V
Attenuance (ATTNDR01) Attenuance (m -1 ) = (-1/path length) x ln(decimal transmittance) path length = 0.25 m, decimal transmittance (Tr) = light transmission (%) / 100.

Fluorometer

Channel Manufactuers Calibration equation Coefficient Values
Fluorescence (CPHLUMTF) Chl. a (µg l -3 ) = Scale Factor x (FVLTWS01 - Clean Water Offset) Scale Factor = 15.1 µg l -1 V -1 , Clean Water Offset = 0.065 V

Sample Calibrations

Temperature

The hull temperature sensor data were calibrated against the CTD temperature sensors during the cruise. The data from the hull sensor at the CTD start time were compared with the temperature from the externally mounted CTD temperature at 5 decibars. The temperature offsets (CTD - Hull) were plotted against date/time and CTD sensor temperature and 19 outliers were identified. The relationships in the offset between sensors were then compared to the date/time and the CTD sensor temperature in separate linear regressions. There was not a significant linear dependence between CTD temperature sample value and residual so the mean offset was applied. (R2 = 0.0028; n = 56; F = 0.6993; p = 0.89088 (intercept) and p = 0.6993(slope).

Applying the mean offset between the externally mounted CTD temperature sensor and the hull mounted temperature sensor, the calibrated temperature channel data were generated.

Channel Calibration equation
Hull Temperature TEMPHG01 = TEMPHU01 - 0.01591

Salinity

The SBE45 salinity data were calibrated against bench salinometer data from samples collected from the underway system during the cruise. The data from the SBE45 TSG at the discrete sampling times were compared with the bench salinometer measurements. The salinity offsets (bench - TSG) were plotted against date/time and bench salinity then 17 outliers were identified. The relationships in the offset between TSG and bench salinometer were then compared to bench salinity using a linear regression. Two distinct regions were identified and separate calibrations were applied to both. For calibration 1, the regression of offset against bench salinity was not significant (R2 = 0.0025; n = 48; F = 0.7354; p = 0.701 (intercept) and p =0.735(slope). The regression of offset against linear time was also insignificant, so the mean offset was applied to data from the start of the file till 19/06/2011 16:11.

For calibration 2, the regression of offset against bench salinity was not significant (R2 = 0.0333; n = 57; F = 0.174; p = 0.100 (intercept) and p =0.174(slope). The regression of offset against linear time was significant, so the linear calibration was applied to data from 19/06/2011 16:11 to 09/07/2011 07:25.

Applying the equations from the bench salinometer regressions, the calibrated salinity channel data were generated using the BODC BUDS calibration routine.

Channel Calibration equation Calibration time frame
Salinity calibration 1 PSALSG01 = PSALSU01 - 0.0049 06/06/2011 07:58 to 19/06/2011 16:11
Salinity calibration 2 offset at start = -0.0049; offset at end = 0.0443 19/06/2011 16:11 to 09/07/2011 07:25

Project Information

UKOARP Theme B: Ocean acidification impacts on sea surface biology, biogeochemistry and climate

The overall aim of this theme is to obtain a quantitative understanding of the impact of ocean acidification (OA) on the surface ocean biology and ecosystem and on the role of the surface ocean within the overall Earth System.

The aims of the theme are:

The main consortium activities will consist of in-situ measurements on three dedicated cruises, as well as on-deck bioassay experiments probing the response of the in-situ community to elevated CO2. Most of the planned work will be carried out on the three cruises to locations with strong gradients in seawater carbon chemistry and pH; the Arctic Ocean, around the British Isles and the Southern Ocean.

Weblink: http://www.oceanacidification.org.uk/research_programme/surface_ocean.aspx


Data Activity or Cruise Information

Cruise

Cruise Name D366 (D367)
Departure Date 2011-06-06
Arrival Date 2011-07-09
Principal Scientist(s)Eric Pieter Achterberg (University of Southampton School of Ocean and Earth Science)
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