Metadata Report for BODC Series Reference Number 701698


Metadata Summary

Data Description

Data Category Hydrography time series at depth
Instrument Type
NameCategories
Aanderaa RCM 7/8 Recording Current Meter  current meters
Instrument Mounting moored surface buoy
Originating Country United Kingdom
Originator Mr John Howarth
Originating Organization Proudman Oceanographic Laboratory (now National Oceanography Centre, Liverpool)
Processing Status banked
Project(s) Coastal Observatory
 

Data Identifiers

Originator's Identifier POL926B/AACM9631
BODC Series Reference 701698
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2005-05-12 08:35
End Time (yyyy-mm-dd hh:mm) 2005-06-16 08:25
Nominal Cycle Interval 600.0 seconds
 

Spatial Co-ordinates

Latitude 53.45217 N ( 53° 27.1' N )
Longitude 3.64133 W ( 3° 38.5' W )
Positional Uncertainty 0.0 to 0.01 n.miles
Minimum Sensor Depth 10.0 m
Maximum Sensor Depth 10.0 m
Minimum Sensor Height 12.4 m
Maximum Sensor Height 12.4 m
Sea Floor Depth 22.4 m
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 Instantaneous - Depth measured below water line or instantaneous water body surface
Sea Floor Depth Datum Instantaneous - Depth measured below water line or instantaneous water body surface
 

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)
ACYCAA01 1 Dimensionless Record_No Sequence number
CNDCPR01 1 Siemens per metre InSituCond Electrical conductivity of the water body by in-situ conductivity cell
PSALPR01 1 Dimensionless P_sal Practical salinity of the water body by conductivity cell and computation using UNESCO 1983 algorithm
TEMPPR01 1 Degrees Celsius Temp Temperature of the water body
 

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

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

Data Processing Notes

Data Originator's Processing

The following procedures were carried out before the data were supplied to BODC.

Data were downloaded from the instrument logger, and factory calibrations were applied to the conductivity, temperature and pressure channels, when present.

BODC Data Processing and Quality Control

Where pressure sensors were fitted: the data record was compared with the instrument depth to ensure it was giving reasonable values for that depth. It should be noted that pressure sensors on these instruments were generally used as in indication of rig disturbance and the pressure readings were not suitable for any other use. The time series was visually screened for evidence of rig movement (e.g. trawling) and excessive leaning (perhaps due to strong currents).

Where temperature sensors were fitted: the data record was compared with other temperature data taken in the vicinity and checked for agreement within a few tenths of a degree Celsius. Obvious spikes were flagged. Periods of excessively noisy data were noted.

Conductivity sensors: salinity (PSS-78) was computed during transfer using the Matlab sw_salt routine:

where

General Data Screening carried out by BODC

BODC screen both the series header qualifying information and the parameter values in the data cycles themselves.

Header information is inspected for:

Documents are written by BODC highlighting irregularities which cannot be resolved.

Data cycles are inspected using time or depth series plots of all parameters. Currents are additionally inspected using vector scatter plots and time series plots of North and East velocity components. These presentations undergo intrinsic and extrinsic screening to detect infeasible values within the data cycles themselves and inconsistencies as seen when comparing characteristics of adjacent data sets displaced with respect to depth, position or time. Values suspected of being of non-oceanographic origin may be tagged with the BODC flag denoting suspect value; the data values will not be altered.

The following types of irregularity, each relying on visual detection in the plot, are amongst those which may be flagged as suspect:

If a large percentage of the data is affected by irregularities then a Problem Report will be written rather than flagging the individual suspect values. Problem Reports are also used to highlight irregularities seen in the graphical data presentations.

Inconsistencies between the characteristics of the data set and those of its neighbours are sought and, where necessary, documented. This covers inconsistencies such as the following:

This intrinsic and extrinsic screening of the parameter values seeks to confirm the qualifying information and the source laboratory's comments on the series. In screening and collating information, every care is taken to ensure that errors of BODC making are not introduced.


Project Information

Proudman Oceanographic Laboratory Coastal Observatory

The Coastal Observatory was established by Proudman Oceanographic Laboratory as a coastal zone real time observing and monitoring system. The main objective is to understand a coastal sea's response both to natural forcing and to the consequences of human activity. Near real-time measurements will be integrated with coupled models into a pre-operational coastal prediction system whose results will be displayed on the World Wide Web.

The Observatory is expected to grow and evolve as resources and technology allow, all the while building up long time series. A site selection pilot study was carried out in September 2001 and the Observatory became operational in August 2002.

The site is located in Liverpool Bay and is subject to typical coastal sea processes, with strong tides, occasional large storm surges and waves, freshwater input, stable and unstable stratification, high suspended sediment concentration and biogeochemical interaction. Measurements and monitoring will focus on the impacts of storms, variations in river discharge (especially the Mersey), seasonality and blooms in Liverpool Bay.

A variety of methods will be used to obtain measurements, including:

  1. Moored instruments for in situ time series of currents, temperature and salinity profiles, and surface waves and meteorology. It is hoped that turbidity and chlorophyll measurements will be made at another site as the Observatory progresses;
  2. The Cefas Smartbuoy for surface properties such as nutrients and chlorophyll, starting late 2002;
  3. R.V. Prince Madog to carry out spatial surveys and service moorings;
  4. Instrumented ferries for near surface temperature, salinity, turbidity, chlorophyll and nutrients. The first route will be Liverpool to Douglas, Isle of Man, starting late 2002;
  5. Drifters for surface currents and properties such as temperature and salinity, starting in 2004;
  6. Tide gauges, with sensors for meteorology, waves, temperature and salinity, where appropriate;
  7. Meteorological data from Bidston Observatory and Hilbre Island, HF radar and tide gauge sites;
  8. Shore-based HF radar measuring waves and surface currents out to a range of 50 km, starting in 2003;
  9. Satellite data, with infrared for sea surface temperature and visible for chlorophyll and suspended sediment.

The partners currently involved with the project are listed below:

A summary of Coastal Observatory cruises to date on R.V. Prince Madog is given in the table below:

Year No. of cruises Work summary
2001 1 Site selection and pilot study. 95 CTD casts.
2002 4 POL moorings deployed and serviced
Cefas Waverider and SmartBuoy deployed and serviced
103 CTD casts
2003 10 POL moorings serviced
Cefas Waverider and SmartBuoy serviced
341 CTD/LISST casts
2004 9 POL moorings serviced
Cefas Waverider and SmartBuoy serviced
347 CTD/LISST casts
2005 9 POL moorings serviced
Cefas Waverider and SmartBuoy serviced
268 CTD/LISST casts
2006 11 POL moorings serviced
Cefas Waverider and SmartBuoy serviced
508 CTD/LISST casts
2007 9 POL moorings serviced
Cefas Waverider and SmartBuoy serviced
471 CTD/LISST casts
2008 9 POL moorings serviced
Cefas Waverider and SmartBuoy serviced
260 CTD/LISST casts
2009 7 POL moorings serviced
Cefas Waverider and SmartBuoy serviced
213 CTD/LISST casts
2010 8 POL moorings serviced
Cefas Waverider and SmartBuoy serviced
268 CTD/LISST casts
2011 6 POL moorings serviced
Cefas Waverider and SmartBuoy serviced
307 CTD/LISST casts to date, ongoing

Data Activity or Cruise Information

Data Activity

Start Date (yyyy-mm-dd) 2005-05-12
End Date (yyyy-mm-dd) 2005-06-16
Organization Undertaking ActivityProudman Oceanographic Laboratory (now National Oceanography Centre, Liverpool)
Country of OrganizationUnited Kingdom
Originator's Data Activity IdentifierPOLRIG926
Platform Categorymoored surface buoy

Smartbuoy deployment LB2_001 / POLRIG#926

Deployment and Recovery

This rig was deployed as part of the Liverpool Bay Coastal Observatory during R.V. Prince Madog cruise PD18_05. Recovery of the rig took place during R.V. Prince Madog cruise PD21_05.

Rig Position 53 27.134N, 3 38.482W
Water Depth 22.4m
Deployed 12 May 2005 08:25:00 GMT
Recovered 16 June 2005 08:37:00 GMT
No. of Days 35

This rig is a single line mooring, comprising a surface CEFAS SmartBuoy along with a Sea-Bird MicroCAT and an Aanderaa current meter attached at depth on the mooring line. The single point mooring was composed mainly of half inch long link chain, marked at the surface by a 1.8 m diameter toroid (the CEFAS SmartBuoy) and anchored by a half tonne clump of scrap chain. This rig was deployed as part of the Liverpool Bay Coastal Observatory during R.V. Prince Madog cruise PD18_05.

The CEFAS SmartBuoy is fitted with a surface CTD (including turbidity and chlorophyll fluorescence sensors) and a water sampler which obtains water samples once per day for laboratory nutrient (nitrate, nitrite, phosphate) determination. In addition A Druck 5 bar pressure transducer, a battery monitor and an analog roll / pitch device were attached to the buoy. The CTD and light data are transmitted back to CEFAS via Orbcomm.


The table below details the CEFAS instrumentation


Eco System Monitor - V2a (UL025)

Instrument Serial
Number
Parameters Meter
depth (m)
Record
Length (days)
Chelsea Instruments Minitracka Fluorometer 2211 Chlorophyll
Fluorescence
1 35
Falmouth Scientific OEM CT sensor 1406 Temperature
Conductivity
(Salinity Derived)
1 35
Seapoint Turbidity meter 1434 Turbidity 1 35
Druck 5 bar Pressure Transducer 1759544 Pressure (ADCP and telemetry) 1 No information available
Analog Devices Roll / Pitch 25 Roll
Pitch
1 No information available
Battery Monitor 25 Battery 1 No information available

Stand Alone Sensors

Instrument Serial
Number
Parameters Meter
depth (m)
Record
Length (days)
WMS-2 Aqua Monitor 2643 Silicate
Suspended Load
Total Oxidised Nitrogen
1 32

The table below details the POL instrumentation
Instrument Serial Number DSU Number Meter Level Parameters Measured Sampling Interval Comments
Sea-Bird MicroCAT SBE37-SM 485 V2.2 2991 - 5 m below surface Temperature
Conductivity
10 minutes Upon recovery the clock was found to be running 10 s fast.
Aanderaa current meter RCM7 9631 8117 10 m below surface Temperature
Conductivity
10 minutes No fin; used only to log temperature (low temperature setting) and conductivity.
Upon recovery the clock was found to be running 22 s fast.

DSU = Data Storage Unit

Other Series linked to this Data Activity - 701717 1195155 1195118 1195131 1195143

Cruise

Cruise Name PD18/05
Departure Date 2005-05-11
Arrival Date 2005-05-13
Principal Scientist(s)Phil J Knight (Proudman Oceanographic Laboratory)
Ship RV Prince Madog

Complete Cruise Metadata Report is available here


Fixed Station Information

Fixed Station Information

Station NameCoastal Observatory Site 21
CategoryOffshore location
Latitude53° 27.13' N
Longitude3° 38.48' W
Water depth below MSL25.0 m

Liverpool Bay Coastal Observatory Site 21

This station is one of 34 stations regularly visited by the Proudman Oceanographic Laboratory (POL) as part of the Liverpool Bay Coastal Observatory. The main activity at this site are CTD profiles (since August 2002) which are taken during each site visit. This station was also the secondary mooring site (also referred to as Site B) for the Coastal Observatory project between April 2005 and March 2010. After March 2010 the moorings were moved to site 20. The station lies within a box of mean water depth 24 m with the following co-ordinates:

Box Corner Latitude (+ve North) Longitude (+ve East)
North-west corner 53.46028 -3.658
South-east corner 53.44249 -3.6105

The position of this station relative to the other POL Coastal Observatory sites can be seen from the figure below.

BODC image

Mooring Deployment History

2010

Rig Type Typical Instruments Rig IDs Comment
Frame ADCP, CTD, OBS, Telemetry ADCP 1088, 1092, 1096, 1100, 1104, 1107, 1111 January - December
SmartBuoy CT, FL, OBS, BD 1087, 1091, 1095, 1099, 1103, 1110, 1115 January - December

2009

Rig Type Typical Instruments Rig IDs Comment
Frame ADCP, CTD, OBS, Telemetry ADCP 1057, 1065, 1069, 1072, 1076, 1080, 1084 January - December
SmartBuoy CT, FL, OBS, BD 1056, 1064, 1068, 1075, 1079, 1083 January - December

2008

Rig Type Typical Instruments Rig IDs Comment
Frame ADCP, CTD, OBS, Telemetry ADCP 1026, 1030, 1033, 1038, 1053 January - December
SmartBuoy CT, FL, OBS, BD LB2_023/1025, LB2_024/1029, LB2_025/1034, LB2_026/1037, LB2_029/1052 January - December

2007

Rig Type Typical Instruments Rig IDs Comment
Frame ADCP, CTD, OBS, Telemetry ADCP 992, 999, 1002, 1007, 1012, 1019 January - December
SmartBuoy CT, FL, OBS, BD 991, LB2_016/998, LB2_017/1003, LB2_018/1006, LB2_019/1011, LB2_020/1015, LB2_021/1018, LB2_022/1022 January - December

2006

Rig Type Typical Instruments Rig IDs Comment
Frame ADCP, CTD, OBS, Telemetry ADCP 952, 960, 964, 968, 972, 976, 980, 984, 988 January - December
SmartBuoy CT, FL, OBS, BD LB2_006, LB2_007, LB2_008, LB2_009, LB2_010, LB2_011, LB2_012, LB2_013/983, LB2_014/987 January - December

2005

Rig Type Typical Instruments Rig IDs Comment
Frame ADCP, CTD, OBS 923, 927, 931, 936, 940, 943, 947, 950 January - December
SmartBuoy CT, FL, OBS, WMS LB2_001/926, LB2_002/930, LB2_003/935, LB2_004/939, LB2_005/946 May - December
Marker buoy CT 922 April - May

CTD Sampling History

Year Number of Cruises Total Casts per year
2011 5 5
2010 6 6
2009 7 18
2008 9 16
2007 8 17
2006 9 18
2005 9 14
2004 8 8
2003 9 9
2002 2 2

The CTD instrument package for these cruises was a Sea-Bird 911plus, with beam transmissometer, fluorometer, LICOR PAR sensor, LISST-25, and oxygen sensor.

Key

ADCP = Acoustic Doppler Current Profiler
BD = Bacterial degradation experiment
CT = Conductivity and temperature logger
CTD = Conductivity, temperature, depth sensor
FL = Fluorometer
OBS = Optical Backscatter Turbidity meter
Telemetry ADCP = ADCP sending data back to shore in real-time
WMS = Automatic water sampler

Other Series linked to this Fixed Station for this cruise - 701717 701883 1195118 1195131 1195143 1195155 1622731

Other Cruises linked to this Fixed Station (with the number of series) - PD01/08 (12) PD01/11 (1) PD02/07 (4) PD02/09B (11) PD02/10 (1) PD04/06 (4) PD04/07 (4) PD06/07 (9) PD07/08 (9) PD07/11 (1) PD09/07 (9) PD09/08 (11) PD11/05 (3) PD11/11 (1) PD12/06 (4) PD12/09 (11) PD13/07 (11) PD14/08 (10) PD16/06 (4) PD16/07 (10) PD17/10 (5) PD18/09 (10) PD19/08 (2) PD20/06 (4) PD20/07 (7) PD21/05 (8) PD21/10 (1) PD22/06 (4) PD23/07 (10) PD23/08 (7) PD24/09 (5) PD25/05 (8) PD25/06 (4) PD27/07 (9) PD29/06 (4) PD29/08 (9) PD29/10 (1) PD30/05 (7) PD33/08 (1) PD33/09 (12) PD34/05 (2) PD35/06 (7) PD36/10 (1) PD37/06 (7) PD37/08 (11) PD38/09 (9) PD41/05 (6) PD43/11 (1) PD47/09 (11) PD48/05 (2) PD49/10 (1)


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