Metadata Report for BODC Series Reference Number 648465


Metadata Summary

Data Description

Data Category Currents -subsurface Eulerian
Instrument Type Acoustic doppler current profiler
Instrument Mounting lowered unmanned submersible
Originating Country United Kingdom
Originator -
Originating Organization Southampton Oceanography Centre (now National Oceanography Centre, Southampton)
Processing Status QC in progress
Project(s) Marine Productivity
 

Data Identifiers

Originator's Identifier B14206
BODC Series Reference 648465
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2001-11-10 21:15
End Time (yyyy-mm-dd hh:mm) 2001-11-10 23:18
Nominal Cycle Interval 2.0 seconds
 

Spatial Co-ordinates

Latitude 55.32793 N ( 55° 19.7' N )
Longitude 33.45419 W ( 33° 27.3' W )
Positional Uncertainty 0.0 to 0.01 n.miles
Minimum Sensor Depth 9.88 m
Maximum Sensor Depth 2464.11 m
Minimum Sensor Height -
Maximum Sensor Height -
Sea Floor Depth -
Sensor Distribution Variable common depth - All sensors are grouped effectively at the same depth, but this depth varies significantly during the series
Sensor Depth Datum Instantaneous - Depth measured below water line or instantaneous water body surface
Sea Floor Depth Datum -
 

Parameters

BODC CODE Rank Units Short Title Title
DISTTRAN 0 Metres Tran_dist Distance (from transducer along measurement axis)
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
PRESPR01 1 Decibars Pres_Z Pressure (spatial co-ordinate) exerted by the water body by profiling pressure sensor and corrected to read zero at sea level
ACBSA600 2 Decibels Sv_600kHz Acoustic backscatter (absolute) in the water body by 600kHz broadband acoustic doppler current profiler (ADCP) and calibration using protocols of Deines (1999)
 

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


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

RRS Discovery 258 600khz Lowered ADCP (LADCP)- Absolute backscatter

Deployment and originators processing

The 600 kHz Workhorse LADCP was new to SOC on this cruise. The instrument proved accessible only via the RDI Workhorse application. The main interest in the 600 kHz ADCP for the cruise was the backscatter calculation. Velocity calculations produced no sensible on-board results for the configuration selected and required further investigation. However, after a range correction (see cruise report for details), the calibrated backscatter data seem to correlate with biology in the water column. The instrument setup for the majority of casts is listed in the following table. Deviations are stations 14213, 14214, 14223, 14231 and 14244 where the bin length was 800cm and 14239 where the bin length was 400cm.

Frequency of instrument (kHz) 600
Number of bins: 30
Beam angle 20.0
Number of pings per ensemble 1
Bin length (cm) 200
Blank before transmit (cm) 88

Absolute backscatter coefficient was calculated by the method of Deines (1990). The coefficients used are listed in the table below.

Coefficient  
Alpha 0.153
C -141.4
PdbW 15.4
Rayliegh distance 2.9

Occasionally there were problems with time stamps. The profiles marked suspect in the table below are where there was disagreement between the ADCP depth and CTD depth.

Station No. Status Comments
14191 Processed  
14199 Processed  
14200 Processed  
14205 Processed  
14206 Processed  
14211 Processed  
14212 Processed  
14213 Processed  
14214 Processed  
14215 Processed  
14223 Processed  
14231 Processed  
14239 Processed  
14244 Processed  
14245 Processed  
14249 Failed  
14254 Time problem  
14259 Processed Suspect profile
14263 Processed  
14267 Processed  
14275 Failed  
14283 Processed  
14287 Processed Suspect profile
14288 Processed  
14289 Processed  
14294 Processed  
14295 Processed  

BODC processing

A total of 24 station files where submitted to BODC. The Data were supplied in Matlab binary format. The following variables were transferred to BODC QXF format. A large number of additional variables, including CTD and navigation data, were also present in the files. These were not transferred.

Description Units Originators variable
Pressure Decibars d.z
Absolute backscatter (MVBS) Decibels d.mvbs
Distance from transducer Metres d.zd

Screening and Data quality

The data have been visually screened for obvious problems using the BODC XERPLO software. No significant problems were detected.

References

RDI, (1990). Calculating Absolute Backscatter. Technical bulletin ADCP-90-04, R D Instruments, San Diego, CA, USA.


Project Information

Marine Productivity programme (MarProd)

The Marine Productivity programme (MarProd) was a Thematic Programme of the Natural Environment Research Council. It was funded for a period of five years starting in 2000. Its main goal was "to develop coupled modelling and observation systems for the pelagic ecosystem, with emphasis on physical factors affecting zooplankton dynamics" with the following specific objectives:

The programme was composed of two phases: Phase 1 projects (2000-2002) focused on the use of historical datasets and existing biological models, complemented by laboratory experiments and remote-sensing analyses to gain a better understanding of the dynamics of zooplankton populations in shelf seas. The main, field-based Phase 2 of the programme (2001-2005) focused on the open ocean. The fieldwork phase took place between November 2001 and December 2002 and consisted of four surveys in the northern North Atlantic in early winter 2001 and 2002, and in spring and summer 2002.

MarProd was a major UK contribution to the international Global Ocean Ecosystem Dynamics project (GLOBEC).


Data Activity or Cruise Information

Cruise

Cruise Name D258
Departure Date 2001-11-01
Arrival Date 2001-12-18
Principal Scientist(s)Raymond T Pollard (Southampton Oceanography Centre), Steven J Hay (Fisheries Research Services Aberdeen Marine Laboratory)
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