Metadata Report for BODC Series Reference Number 1199795


Metadata Summary

Data Description

Data Category Multiple data types -ship
Instrument Type
NameCategories
WETLabs WETStar fluorometer  fluorometers
Sea-Bird SBE 45 MicroTSG thermosalinograph  thermosalinographs; water temperature sensor; salinity sensor
WETLabs ECO-VSF Optical Backscatter Meter  optical backscatter sensors
WETLabs ac-9 Absorption and Attenuation meter  transmissometers
Instrument Mounting research vessel
Originating Country United States
Originator Dr Barney Balch
Originating Organization Bigelow Laboratory for Ocean Sciences
Processing Status banked
Project(s) Atlantic Meridional Transect Phase2(AMT)
 

Data Identifiers

Originator's Identifier AMT17.XLS
BODC Series Reference 1199795
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2005-10-16 15:59
End Time (yyyy-mm-dd hh:mm) 2005-11-26 04:34
Nominal Cycle Interval 360.0 seconds
 

Spatial Co-ordinates

Start Latitude 51.98930 N ( 51° 59.4' N )
End Latitude 35.53330 S ( 35° 32.0' S )
Start Longitude 5.87550 W ( 5° 52.5' W )
End Longitude 18.61050 E ( 18° 36.6' 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
LAMBIN01 0 Nanometres Wavelength Wavelength of electromagnetic radiation measurement
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)
ACYCAA01 1 Dimensionless Record_No Sequence number
ALATGP01 1 Degrees Lat_GPS Latitude north (WGS84) by unspecified GPS system
ALONGP01 1 Degrees Lon_GPS Longitude east (WGS84) by unspecified GPS system
BS532VSF 1 per metre attn_backscat_532nm Attenuation due to backscatter (532nm wavelength) in the water body by scattering photometer and calibration to read zero in clear water with computation from volume scatter data
CPHLUT01 1 Milligrams per cubic metre chl-a_water_NTTFfluor_sampcal 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 calibration against sample data
PSALSU01 1 Dimensionless P_sal_TSG_uncalib Practical salinity of the water body by thermosalinograph and computation using UNESCO 1983 algorithm and NO calibration against independent measurements
TEMPSU01 1 Degrees Celsius UncalTSGTmp Temperature of the water body by thermosalinograph and NO verification against independent measurements
ABSPXAC9 2 per metre absorb_cwoffset_2D Absorbance of electromagnetic radiation (unspecified single wavelength) {light absorbance} by the water body by transmissometer and calibration to read zero in clear water
ABSULT01 2 per metre absorb_lt0_2um Absorbance of electromagnetic radiation (unspecified single wavelength) {light absorbance} per unit length of the water body [dissolved plus reactive particulate <0.2um phase] by transmissometer and calibration to read zero in clear water
ATTNXAC9 2 per metre attn_cwoffset_2D Attenuation (unspecified single wavelength) per unit length of the water body by transmissometer and calibration to read zero in clear water
 

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

AMT Bio-Optics Data Quality - Flow-through measurements

The data were screened using the BODC in-house software, Edserplo.

All parameters had 'N' flags applied during transfer for any null data. 'M' flags were automatically assigned during transfer to values outside the minimum and maximum permissable values. Data were occasionally manually flagged with 'M' during screening when the data scientist considered the data to be suspect. This included solitary spikes and periods when the instrument might be adjusting to conditions after failure, redeployment or period of null data.

The light parameters (ATTNXAC9, ABSULT01 and ABSPXAC9) regularly have periods of null data.


Data Access Policy

Academic domain data

These data have no specific confidentiality restrictions for academic users. However, users must acknowledge data sources as it is not ethical to publish data without proper attribution. Any publication or other output resulting from usage of the data should include an acknowledgment.

The recommended acknowledgment is:

"This study uses data from data source/organisation/programme, provided by the British Oceanographic Data Centre and funded by the funding body."


Narrative Documents

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 .

AMT Bio-Optics Instrumentation - Flow-through measurements

Instrument Serial number Parameter
WET Labs ECO-VSF 061g Total optical backscattering at 532 nm
WET Labs WETStar fluorometer 1048p Chlorophyll fluorescence
WET Labs ac-9 Spectrophotometer 194 Absorption and attenuation
SeaBird SBE45 4530785-0102 Temperature and Salinity

WETLabs ECO-VSF Optical Backscatter Meter

The ECO-VSF is a scattering meter designed to measure the angular distribution of scattered radiation of the backward hemisphere. The instrument measures optical scattering at three angles (100°, 125° and 150°), providing the shape of the Volume Scattering Function (VSF) throughout the backscattering region. Interpolation and extrapolation are used to determine scattering at intermediate angles. It also provides the total backscatter coefficient between 90° and 180° by integration and extrapolation.

The ECO-VSF comes in five versions, with a variety of power options, sampling strategies and anti-fouling capabilities:

The specifications below are common to all versions.

Specifications

Wavelength 470, 532 or 660 nm
Sensitivity 1.24x10 -5
Typical range ~ 0.0012-5 m -1
Linearity 99 % R 2
Temperature range 0-30°
Depth rating 600 m (standard)
Sample rate up to 8 Hz
Pressure sensor optional
Temperature sensor optional

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

WETLabs ac-9 and ac-s Spectral Absorption and Attenuation Meters

The WETLabs ac-9 and ac-s meters measure the spectral transmittance and spectral absorption of water, allowing determination of absorption and beam attenuation coefficients. The instruments incorporate a flow-through system and a dual path configuration that permits concurrent measurement of both coefficients along a 25 cm path. The ac-9 provides measurements at nine wavelengths in the range 412-715 nm, whereas the ac-s provides measurements at >80 wavelengths from 400-730 nm.

Specifications

Parameters ac-9 ac-s
Temperature range 0-30 ° 0-30 °
Rated depth 500 or 5000 m 500 m
Spectral range 412-715 nm 400-730 nm
Band-pass 10 nm per channel 15 nm per channel
Pathlength 25 cm (optional 10 cm) 25 cm (optional 10 cm)
Beam cross-section 8 mm dia. (nominal) 8 mm dia. (nominal)
Linearity >=99 % R 2 >=99 % R 2
Wavelength output 9 80-90 in 4 nm steps
Accuracy ±0.01 m -1 ±0.01 m -1
Dynamic range 0.001-10 m -1 0.001-10 m -1

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

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 .

AMT Bio-Optics - Flow-through Processing Document

Data Acquisition and Analysis

This system operates semi-continuously with water from the ship's non-toxic sea water supply Every 4-12 minutes temperature and salinity are measured (with a SeaBird sensor), chlorophyll fluorescence (WET Labs WETStar), total backscattering at 532 nm (bbtot; WET Labs ECO-VSF), acidified backscattering (bbacid; backscattering of the seawater suspension after the pH has been lowered to dissolve calcite and aragonite), and acid-labile backscattering (bb'; the difference between the bbtot and bbacid). The chlorophyll data were calibrated against sample data.

BODC Data Processing Procedures

Data were submitted to BODC as a .out file, which was then saved to the archive following BODC procedure. Date were submitted in a .out text file containing temperature, salinity and fluorescence from sea surface water from the ship's non-toxic water supply. Light absorption and attenuation were also supplied at 9 different wavelengths along with the backscattering and acid labile backscattering. Additional metadata was supplied including: cruise, latitude, longitude, date and time. The MicroSAS radiance parameters were also submitted in the same file but banked separately to the NODB.

The data were converted from the comma delimited SeaBass format into BODC internal format using a standard BODC transfer.

Parameter codes defined in BODC parameter dictionary were assigned to the variables as shown in the table below. No unit conversions were necessary as the data submitted was already units from the BODC parameter dictiionary.

Parameter Mapping Table

Originator's Parameter Description Units BODC Parameter Code Description Units Comments
lat Latitude, as mentioned on the originator's file degrees ALATGP01 Latitude north (WGS84) by unspecified GPS system Global Positioning System (receiver type unspecified) degrees N/A
lon Longitude, as mentioned on the originator's file degrees ALONGP01 Longitude east (WGS84) by unspecified GPS system Global Positioning System (receiver type unspecified) degrees N/A
bbp532 Backscattering coefficient of particles(*) m -1 BS532VSF Attenuance due to backscatter (532nm wavelength) in the water body by scattering photometer and calibration to read zero in clear water with computation from volume scatter data m -1 N/A
agp Absorption Coefficient of Gelbstoff + particles(*) m -1 ABSPXAC9 Light absorbance (unspecified single wavelength) by the water body by transmissometer and calibration to read zero in clear water m -1 N/A
ag Absorption Coefficient of Gelbstoff(*) m -1 ABSULT01 Light absorbance (unspecified single wavelength) per unit length of the water body dissolved plus reactive particulate <0.2 µm by transmissometer and calibration to read zero in clear water m -1 N/A
cgp Absorption Coefficient of Gelbstoff + particles(*) m -1 ATTNXAC9 Attenuance (unspecified single wavelength) per unit length of the water body by transmissometer and calibration to read zero in clear water m -1 N/A
wavelength Wavelength(*) nm LAMBIN01 Wavelength of electromagnetic radiation measurement nm N/A
Sal Salinity - PSALSU01 Practical salinity of the water body by thermosalinograph and computation using UNESCO 1983 algorithm and NO calibration against independent measurements - N/A
Temp Water temperature degrees Celsius TEMPSU01 Temperature of the water body by thermosalinograph and NO verification against independent measurements degrees Celsius N/A
Chl Fluorometrically/spectrophotometrically-derived chlorophyll a(*) mg m -3 CPHLUT01 Concentration of chlorophyll-a {chl-a} per unit volume of the water body [particulate >unknown phase] by through-flow fluorometer plumbed into non-toxic supply and calibration against sample data. mg m -3 N/A

Screening

Once transferred the reformatted data were imported into the BODC in-house visualisation software, Edserplo. Data were appropriately flagged and double checked for any anomalous results. Further details are given in the data quality report.


Project Information

The Atlantic Meridional Transect - Phase 2 (2002-2006)

Who was involved in the project?

The Atlantic Meridional Transect Phase 2 was designed by and implemented by a number of UK research centres and universities. The programme was hosted by Plymouth Marine Laboratory in collaboration with the National Oceanography Centre, Southampton. The universities involved were:

What was the project about?

AMT began in 1995, with scientific aims to assess mesoscale to basin scale phytoplankton processes, the functional interpretation of bio-optical signatures and the seasonal, regional and latitudinal variations in mesozooplankton dynamics. In 2002, when the programme restarted, the scientific aims were broadened to address a suite of cross-disciplinary questions concerning ocean plankton ecology and biogeochemistry and the links to atmospheric processes.

The objectives included the determination of:

The data were collected with the aim of being distributed for use in the development of models to describe the interactions between the global climate system and ocean biogeochemistry.

When was the project active?

The second phase of funding allowed the project to continue for the period 2002 to 2006 and consisted of six research cruises. The first phase of the AMT programme ran from 1995 to 2000.

Brief summary of the project fieldwork/data

The fieldwork on the first three cruises was carried out along transects from the UK to the Falkland Islands in September and from the Falkland Islands to the UK in April. The last three cruises followed a cruise track between the UK and South Africa, only deviating from the traditional transect in the southern hemisphere. During this phase the research cruises sampled further into the centre of the North and South Atlantic Ocean and also along the north-west coast of Africa where upwelled nutrient rich water is known to provide a significant source of climatically important gases.

Who funded the project?

Natural Environment Research Council (NERC)


Data Activity or Cruise Information

Cruise

Cruise Name D299 (AMT17)
Departure Date 2005-10-15
Arrival Date 2005-11-28
Principal Scientist(s)Patrick M Holligan (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