Search the data

Metadata Report for BODC Series Reference Number 1623015


Metadata Summary

Data Description

Data Category Currents -subsurface Eulerian
Instrument Type
NameCategories
Aanderaa RCM 7/8 Recording Current Meter  current meters
Instrument Mounting mooring
Originating Country United Kingdom
Originator Prof Raymond Pollard
Originating Organization Southampton Oceanography Centre (now National Oceanography Centre, Southampton)
Processing Status QC in progress
Online delivery of data Download not available
Project(s) CROZEX
 

Data Identifiers

Originator's Identifier M3RCM050
BODC Series Reference 1623015
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2004-11-13 08:30
End Time (yyyy-mm-dd hh:mm) 2005-01-09 07:58
Nominal Cycle Interval 10.0 seconds
 

Spatial Co-ordinates

Latitude 46.05780 S ( 46° 3.5' S )
Longitude 51.72613 E ( 51° 43.6' E )
Positional Uncertainty Unspecified
Minimum Sensor or Sampling Depth 505.0 m
Maximum Sensor or Sampling Depth 505.0 m
Minimum Sensor or Sampling Height 1535.0 m
Maximum Sensor or Sampling Height 1535.0 m
Sea Floor Depth 2040.0 m
Sea Floor Depth Source CRREP
Sensor or Sampling Distribution Fixed common depth - All sensors are grouped effectively at the same depth which is effectively fixed for the duration of the series
Sensor or Sampling Depth Datum Instantaneous - Depth measured below water line or instantaneous water body surface
Sea Floor Depth Datum Approximate - Depth is only approximate
 

Parameters

No Parameters for BODC Reference Number = 1623015

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 Quality Report

There are no data for 58 minutes between 04 November 2004 23:10:00 hours and 05 January 2005 00:08 hours.


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

Aanderaa Recording Current Meter Model 7/8

Manufacturer's specifications: recording unit height 49.5cm (RCM8 52.0cm), diameter 12.8cm, vane size 48.5x50.0cm. Meter is designed for depths down to 2000m (RCM8 6000m). It incorporates a spindle which is shackled to the mooring line. The meter is attached to the spindle through a gimbal mounting which permits a maximum 27° deviation of the spindle from the vertical, the meter still remaining horizontal.

Meter comprises :

  1. Paddle wheel rotor magnetically coupled to an electronic counter

  2. Vane, which aligns instrument with current flow, has a balance weight ensuring static balance and tail fins to ensure dynamic balance in flows up to 250cm/s.

  3. Magnetic compass (needle is clamped to potentiometer ring) - direction recorded with 0.35° resolution, 5° accuracy for speeds 5 to 100cm/s, 7.5° accuracy for remaining speeds within 2.5 to 200cm/s range.

  4. Quartz clock, accuracy better than 2 sec/day within temperature range 0 to 20°C.

  5. Thermistor (temperature sensor), standard range -2.46 to 21.48°C (max on high range 36.04°C), accuracy 0.05°C, resolution 0.1 per cent of range, 63 per cent response time 12sec.

  6. Inductive cell conductivity sensor (optional), range 0 to 70mmho/cm standard resolution 0.1 per cent of range.

  7. Silicon piezoresistive bridge, standard range 0 to 3000 psi (RCM8 to 9000 psi), resolution 0.1% of range.

  8. Self balancing potentiometer which converts the output from each sensor into a 10 bit binary number for storage on magnetic tape.

  9. Associated electronics.

A built-in clock triggers the instrument at preset intervals and up to six channels are sampled in sequence. Channel 1 is a fixed reference reading for control purposes and data identification. Channels 2, 3 and 4 represent measurement of temperature, conductivity and pressure. Channels 5 and 6 represent the VECTOR AVERAGED current speed and direction since the previous triggering of the instrument. The number of rotor revolutions and the direction is sampled every 12 seconds and broken into North and East components. Successive components are added and recorded as speed and direction. For recording intervals longer than 10 minutes, speed and direction are sampled 1/50th of recording interval.

It has become common practice in some laboratories to deploy these meters as temperature and conductivity loggers without current measuring capabilities.

The following link will provide the manufacturer specifications:

Manufacturer specifications

BODC Processing

The data were received in Pstar format and converted into BODC internal format following BODC's standard procedures. The following table shows how the variables within the Pstar file were mapped to appropriate BODC parameter codes:

Originator's Parameter Name Units Description BODC Parameter Code Units Comments
time Julian day and hhmmss Date and time - - -
dayofNov Decimal days Date and time - - -
crsetemp - Unknown - - -
cond mS cm-1 Conductivity CNDCZZ01 S m-1 Units converted from mS cm-1 to S m-1 by dividing by 10.
temp °C Temperature TEMPPR01 °C -
dirn Degrees Current direction LCDAZZ01 Degrees -
speed cm s-1 Current speed LCSAEL01 cm s-1 -
east cm s-1 Eastward current velocity LCEWEL01 cm s-1 -
north cm s-1 Northward current velocity LCNSEL01 cm s-1 -
depth m Instrument depth ADEPPS01 m -
press dbar Pressure PRSTPR01 dbar -
salin Dimensionless Salinity PSALPR01 Dimensionless -
potemp °C Potential temperature POTMCV01 °C -

All reformatted data were visualised using the in-house Edserplo software. Suspect and missing data were marked by adding an appropriate quality control flag.

Originator's Data Processing

Sampling Strategy

Data from a Aanderaa RCM 8 current meter were collected on a mooring deployed during the Crozex cruise D285. The mooring was deployed at site M3 north of the Crozet Islands. On arrival at M3 the ship ran south along a ridge on which the mooring was set. The ridge had been chosen from a detailed French chart and a swath bathymetry survey, and the latter proved accurate to pinpoint the ridge crest, as verified by a second pass from west to east.

Data Processing

All instruments were downloaded onboard and preliminary plots made. The data were converted into Pstar format, a binary format used by NOC physical oceanographers to process, plot and archive a range of oceanographic data. No further details about the data processing were provided.


Project Information

CROZet natural iron bloom EXport experiment (CROZEX)

The multidisciplinary CROZet natural iron bloom EXport experiment (CROZEX) was a major component of the Natural Environment Research Council (NERC) funded core strategic project Biophysical Interactions and Controls over Export Production (BICEP). The project is the first planned natural iron fertilisation experiment to have been conducted in the Southern Ocean.

The overall objective of CROZEX was to examine, from surface to sediment, the structure, causes and consequences of a naturally occurring phytoplankton bloom in the Southern Ocean. The Crozet Plateau was chosen as the study area. This area typically exhibits two phytoplankton blooms a year, a primary bloom in that peaks in October and a secondary bloom in December or January. Specific aims with respect to these were to:

  • Determine what limits the primary bloom
  • Determine the cause of the secondary bloom

The project was run by the George Deacon Division (GDD), now Ocean Biogeochemistry and Ecosystems (OBE) at the National Oceanography Centre Southampton (NOCS). Participants from five other university departments also contributed to the project.

The project ran from November 2004 to January 2008 with marine data collection between 3rd November 2004 and 21st January 2005. There were 2 cruises to the Crozet Islands Plateau, which are summarised in Table 1.

Table 1: Details of the RRS Discovery CROZEX cruises.

Cruise No. Dates
D285 3rd November 2004 - 10th December 2004
D286 13th December 2004 - 21st January 2005

The two cruises aimed to survey two areas at different phases of the bloom cycle described above. A control area to the south of the Crozet Islands, which is classified as High Nutrient Low Chorophyll (HNLC), where the blooms do not occur and a second area in the region of the blooms to the north of the Crozet Islands.

Sampling was undertaken at ten major stations (see Pollard et al., 2007) numbered M1 to M10. The following observations/sampling were conducted at each station where possible:

  • Several CTD casts sampling:
    • Iron (using a titanium rig)
    • 234Th
    • Physical parameters (temperature, salinity etc)
    • Oxygen
    • CO2
    • Nutrients using a stainless steel rig including a Lowered Acoustic Doppler Current Profiller (LADCP)
  • At each thorium cast there was an associated Stand Alone Pump System (SAPS) deployment
  • At some stations, a drifting PELAGRA trap was deployed for the duration of the work
  • Megacoring was undertaken at M5 and M6
  • Gravity coring was undertaken at M5, M6 and M10
  • Longhurst Hardy Plankton Recorder (LPHR) tows were undertaken at a few major stations

For each of the major stations (M1 to M10), the following were determined:

  • Primary productivity
  • New Production
  • Phytoplankton community composition
  • Bacterial activity
  • Iron
  • Nutrient drawdown
  • Thorium export

Sampling between major stations included:

  • SeaSoar runs instrumented with:
    • CTD
    • Optical Plankton Counter (OPC)
    • Fast Repetition Rate fluorimeter (FRRf)
  • Physics CTD casts on several lines
  • Argo float deployments
  • Zooplankton nets at nearly every CTD and major station
  • Underway and on-station CO2 measurements
  • Underway nutrients and radium sampling
  • 5 to 6 day ship-board iron-addition incubation experiments
  • Checks against near-real-time satellite and model data
  • Mooring deployments based on the satellite imagery in support of the CROZET (Benthic CROZEX) project.

The CROZEX cruises included 6 extra days in support of the CROZET (Benthic CROZEX) project, whose main cruise took place one year after the CROZEX cruises. The CROZET work undertaken during the CROZEX cruises was primarily the moored sediment trap deployments, although some of the coring work is applicable to both projects.

CROZEX produced significant findings in several disciplines, including confirmation that iron from Crozet fertilised the bloom and that phytoplankton production rates and most export flux estimates were much larger in the bloom area than the HNLC area (Pollard et al. 2007). Many of the project results are presented in a special CROZEX issue of Deep-Sea Research II (volume 54, 2007).

References

Pollard R., Sanders R., Lucas M. and Statham P., 2007. The Crozet natural iron bloom and export experiment (CROZEX). Deep-Sea Research II, 54, 1905-1914.


Data Activity or Cruise Information

Data Activity

Start Date (yyyy-mm-dd) 2004-11-13
End Date (yyyy-mm-dd) 2005-01-09
Organization Undertaking ActivitySouthampton Oceanography Centre (now National Oceanography Centre, Southampton)
Country of OrganizationUnited Kingdom
Originator's Data Activity IdentifierMooring_M3
Platform Categorysubsurface mooring

No Document Information Held for the Series

Cruise

Cruise Name D285
Departure Date 2004-11-03
Arrival Date 2004-12-10
Principal Scientist(s)Raymond T Pollard (Southampton Oceanography Centre)
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
Q value below limit of quantification