Metadata Report for BODC Series Reference Number 646053

Metadata Summary

Data Description
Data Category Offshore sea floor pressure series
Instrument Type
NameCategories
Aanderaa WLR 7 Water Level Recorder  sea level recorders; water temperature sensor
Instrument Mounting fixed benthic node
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 wr0445.872
BODC Series Reference 646053
 

Time Co-ordinates(UT)
Start Time (yyyy-mm-dd hh:mm) 2003-06-26 10:40
End Time (yyyy-mm-dd hh:mm) 2003-07-24 11:00
Nominal Cycle Interval 600.0 seconds
 

Spatial Co-ordinates

Latitude 53.53620 N ( 53° 32.2' N )
Longitude 3.36570 W ( 3° 21.9' W )
Positional Uncertainty 0.05 to 0.1 n.miles
Minimum Sensor Depth 24.5 m
Maximum Sensor Depth 24.5 m
Minimum Sensor Height 0.5 m
Maximum Sensor Height 0.5 m
Sea Floor Depth 25.0 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 Sea floor reference - Depth measured as a height above sea floor but converted into a depth relative to the sea surface according to the same datum as used for sea floor depth (applicable to instrument depths not bathymetric depths)
Sea Floor Depth Datum Instantaneous - Depth measured below water line or instantaneous water body surface
 

Parameters
BODC CODE Rank Units Title
AADYAA01 1 Days Date (time from 00:00 01/01/1760 to 00:00 UT on day)
AAFDZZ01 1 Days Time (time between 00:00 UT and timestamp)
PRSTPS01 1 Decibars Pressure (measured variable) exerted by the water body plus atmosphere by fixed in-situ pressure sensor
TEMPPR01 1 Degrees Celsius 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 Quality Notes series 646378

Temperature

The user should be aware that there may be an offset present in the temperature channel.

When compared with temperature from two other instruments on the same rig, at the same depth, temperature from this instrument was found to be lower by approximately 0.25 degrees throughout the record. Additionally, the start of the record shows an initial spike in temperature, due to slow sensor response, which was flagged suspect.

Data Access Policy

Public domain data

These data have no specific confidentiality restrictions for 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 the data source/organisation/programme, provided by the British Oceanographic Data Centre and funded by the funding body."

Narrative Documents

Aanderaa Bottom Pressure Recorder Model 5/6/7

The water level recorder models 5, 6 and 7 are self-contained, high precision instruments for recording of the water level by precise measurement of hydrostatic pressure. The pressure sensor consists of an oscillating quartz crystal which shifts frequency with the force applied to it. Temperature is measured by a Fenwall thermistor.

The data from the WLR5/6 are stored on magnetic tape; the model 7 employs a solid-state data storage unit.

Specifications

Pressure

Oscillator Frequency 36-40 kHz
Resolution 0.001% of full scale
Integration 40 seconds

Ranges available:

WLR5 0-100psi, 0-400psi (standard), 0-900psi
WLR6 0-5000psi (standard)
WLR7 0-100psi, 0-400psi, 0-900psi

Temperature

The thermistor is a Fenwall GB32JM19

Range -3 °C to +35 °C
Accuracy ±0.1 °C
Resolution 0.04 °C
Response Time 2 minutes

Aanderaa Water Level Recorder Model 7

The Water Level Recorder (WLR) model 7 is a self-contained, high precision instrument specifically designed for recording of ocean water levels through precise measurement of hydrostatic pressure. The WLR records pressure, temperature and conductivity (optional) at regular intervals, enabling precise variations in water level to be calculated. The pressure sensor consists of an oscillating quartz crystal which shifts frequency with the force applied to it. Temperature is measured by a Fenwall thermistor.

The data from the WLR7 are stored in a solid-state data storage unit (DSU) which can store up to 65,500 ten bit, PDC-4 coded words in a set of EEPROMS. Click the link for further details on theWLR7.

Specifications

Pressure

Oscillator Frequency 36-40 kHz
Resolution 0.001% of range
Repeatability ± 0.01% of full scale
Integration 40 s
Ranges available 0 - 700 kPA (60 m) (standard)
0 - 3500 kPa (340 m) (standard)

Temperature

The thermistor is a Fenwall GB32JM19

Range -3 °C to +35 °C
Accuracy ± 0.1 °C
Resolution 0.04 °C
Response Time 30 s

Conductivity (optional)

Sensor Type Conductivity Cell 3094
Ranges 0 - 77 mmho cm-1 (standard)
0 - 42 mmho cm-1 (on request)
Accuracy ± 0.25 mmho cm-1
Resolution 0.1% of range

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

Coastal Observatory BPR Data Processing

Data Processing at POL

Bottom Pressure Recorders deployed during the Coastal Observatory were set up to sample at an interval of 10 minutes. Data processing was carried out at Proudman Oceanographic Laboratory where data were integrated over a 40-second period for each datacycle. The time stamp for each record was adjusted to reflect this integration period.

Pressure from the atmosphere was not removed from the pressure signal, so pressure logged is pressure of the water column plus atmospheric pressure.

Data Processing at BODC

The data were converted from ASCII format into BODC internal format. Total pressure was converted from units of bars to decibars by multiplying the data by 10.

Offshore Sea Floor Pressure 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:

  1. Irregularities such as suspect values.

  2. Inconsistencies between related information, for example depths of meter and sea bed; times of mooring deployment and for start/end of data series; length of record or number of data cycles, the cycle interval, the clock error and the period over which accrued; originator's comments on meter/mooring performance, data quality and parameters measured and the parameters actually present in the data cycles. Documents are written by BODC highlighting irregularities which cannot be resolved.

Data cycles are inspected via time series plots of parameters. These plots undergo intrinsic and extrinsic screening to detect suspect values within the data cycles themselves and inconsistencies when compared with adjacent data sets. Values suspected of being of non oceanographic origin may be tagged with the BODC flag denoting suspect value.

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

  1. Spurious data at the start or end of the record.

  2. Obvious spikes of non oceanographic origin.

  3. A sequence of constant values in consecutive data cycles.

If a large percentage of the data are affected by irregularities, deemed abnormal, then instead of flagging the individual suspect values, a caution may be documented.

Inconsistencies between the characteristics of the data set and those of its neighbours, as for example between the maximum and minimum values of the parameters (spikes excluded) are, where necessary, documented.

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, 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) 2003-06-26
End Date (yyyy-mm-dd) 2003-07-24
Organization Undertaking ActivityProudman Oceanographic Laboratory (now National Oceanography Centre, Liverpool)
Country of OrganizationUnited Kingdom
Originator's Data Activity IdentifierPOLRIG#872
Platform Categorysubsurface mooring

Proudman Oceanographic Laboratory Rig#872

This rig was deployed as part of the Liverpool Bay Coastal Observatory during R.V. Prince Madog cruise PD25_03B.

Recovery of the rig took place during R.V. Prince Madog cruise PD31_03.

No speed or direction was recorded by the Aanderaa current meter.

Rig Position 53.5362° N, 3.3657° W
Water Depth 25m
Deployed 26 June 2003 10:37
Recovered 24 July 2003 11:27

Instrument Meter Height Parameters Measured
ADCP 3644 0.5m above seabed Velocity profile
Aanderaa current meter 11814 with transmissometer Sea-Tech 556 0.5m above seabed Transmittance, temperature, conductivity, pressure
Aanderaa water level recorder 445 0.5m above seabed Pressure, temperature
Sea-Bird MicroCAT 2506 0.5m above seabed Temperature, conductivity, pressure

Other Series linked to this Data Activity - 646305 646182

Cruise

Cruise Name PD25/03B
Departure Date 2003-06-26
Arrival Date 2003-06-27
Principal Scientist(s)M John Howarth (Proudman Oceanographic Laboratory)
Ship RV Prince Madog

Complete Cruise Metadata Report is available here

Fixed Station Information

Fixed Station Information

Station NameCOA
CategoryOffshore area
Latitude53° 31.51' N
Longitude3° 23.00' W
Water depth below MSL26.0 m

Liverpool Bay Coastal Observatory Mooring Site A (COA/Site 1/Site 9)

This station is the main mooring site for the Proudman Oceanographic Laboratory (POL) Liverpool Bay Coastal Observatory and was first occupied in 2002. It is also known both as Coastal Observatory Site 1 and Site 9. POL perform two main types of activities at this station: they deploy moorings; and in addition, they take CTD profiles during each site visit. The station lies within a box of mean water depth 22.5 m with the following co-ordinates:

Box Corner Latitude (+ve North) Longitude (+ve East)
North-west corner 53.54097 -3.42958
South-east corner 53.50945 -3.33714

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

2011

Rig Type Typical Instruments Rig IDs Comment
Frame ADCP, CTD, OBS, OXY 1117 for January cruise. Other frame IDs not available at this time. January - September
SmartBuoy CTD x 2, AC-S, CT x 2, FL x 3, OBS x 2, PAR x 2, WMS, NAS, OXY, T x 2 1116 for January cruise. Other frame IDs not available at this time. January - September
SparBuoy AC-S, FL, CTD x 2, T Frame ID not available at this time. September

2010

Rig Type Typical Instruments Rig IDs Comment
Frame ADCP, CTD, ADV, OBS 1086, 1090, 1094, 1098, 1102, 1106, 1109 January - December
SmartBuoy CT x 2, FL x 2, OBS, PAR x 2, WMS, NAS, CTD, OXY, BD, T 1085, 1089, 1093, 1097, 1101, 1105, 1108, 1112 January - December

2009

Rig Type Typical Instruments Rig IDs Comment
Frame ADCP, CTD, ADV, OBS 1055, 1062, 1067, 1071, 1074, 1078, 1082 January - December
SmartBuoy CT x 2, FL x 2, OBS, PAR x 2, WMS, NAS, CTD, OXY, BD, T 1054, 1061, 1066, 1070, 1073, 1077, 1081 January - December

2008

Rig Type Typical Instruments Rig IDs Comment
Frame ADCP, CTD, ADV, OBS 1024, 1028, 1032, 1036, 1041, 1044, 1047, 1051 January - December
SmartBuoy CT x 2, FL x 2, OBS, PAR x 2, WMS, NAS, CTD, OXY, BD, T LB1_047/1023, LB1_048/1027, LB1_049/1031, LB1_050/1035, 1040, 1043, LB1_053/1050 January - December

2007

Rig Type Typical Instruments Rig IDs Comment
Frame ADCP, CTD, ADV, OBS 990, 997, 1001, 1005, 1010, 1014, 1017, 1021 January - December
SmartBuoy CT x 2, FL x 2, OBS, PAR x 2, WMS, NAS, CTD, OXY, BD, T LB1_039/989, LB1_040/996, LB1_041/1000, LB1_042/1004, LB1_043/1009, LB1_044/1013, LB1_045/1016, LB1_046/1020 January - December

2006

Rig Type Typical Instruments Rig IDs Comment
Frame ADCP, CTD, ADV, OBS 951, 962, 966, 970, 974, 978, 982, 986 January - December
SmartBuoy CT x 2, FL x 2, OBS, PAR x 2, WMS, NAS, CTD, OXY, BD 958, 961, 965, 969, 973, 977, LB1_037/981, LB1_038/985 January - December

2005

Rig Type Typical Instruments Rig IDs Comment
Frame ADCP, CT 913, 914, 921, 925, 929, 933, 938, 942, 945, 949 January - December
SmartBuoy CT, FL, OBS, PAR, WMS, NAS, OXY 912, 920, 924, 928, 932, 937, LB1_028/941, LB1_029/944, LB1_030/948 January - December
Frame with telemetry buoy ADCP 914 March - April

2004

Rig Type Typical Instruments Rig IDs Comment
Frame BPR, ADCP, TR, CT 890, 892, 893, 896, 898, 900, 902, 904, 907, 908, 910, 911 January - December
SmartBuoy CT, FL, OBS, PAR, WMS, NAS 889, 891, 895, 897, 899, 901, 903, 906, 909 January - December
Frame with telemetry buoy ADCP 893, 908, 911 April - May, October - December

2003

Rig Type Instruments Rig IDs Comment
Frame BPR, ADCP, TR, CT 861, 864, 866, 869, 872, 878, 880, 883, 885, 887, 888 January - December
SmartBuoy CT, FL, OBS, PAR, WMS, NAS 863, 865, 867, 870, 871, 877, 879, 882, 884, 886 January - December

2002

Rig Type Instruments Rig IDs Comment
Frame BPR, ADCP, TR, CT 851, 854, 856, 858 August - December
Line mooring CT x 3 853, 855 August - November
SmartBuoy CT, FL, OBS, PAR, WMS, NAS 857, 860 November - December

2001

Rig Type Instruments Rig IDs Comment
Frame ADCP, OBS 838, 839, 840, 841, 843, 844, 845, 846, 848, 849 September

CTD Sampling History

Year Number of Cruises Total Casts per year
2011 6 116 including a 46 cast tidal cycle from 2011-04-18 to 2011-04-19 and a 51 cast tidal cycle station from 2011-07-27 to 2011-07-28
2010 7 69 including a 52 cast tidal cycle station from 2010-04-28 to 2010-04-29
2009 7 21
2008 9 75 including a 54 cast tidal cycle station from 2008-05-13 to 2008-05-14
2007 8 71 including a 51 cast tidal cycle station from 2007-05-15 to 2007-05-16
2006 9 72 including a 53 cast tidal cycle station from 2006-05-09 to 2006-05-10
2005 9 41 including a 22 cast tidal cycle station from 2005-04-05 to 2005-04-06
2004 9 77 including a 54 cast tidal cycle station from 2004-05-11 to 2004-05-12
2003 10 28
2002 4 13

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

AC-S = Absorption and attenuation spectrophotometer
ADCP = Acoustic Doppler Current Profiler
ADV = Acoustic Doppler Velocimeter
BD = Bacterial degradation experiment
BPR = Bottom Pressure Recorder
CT = Conductivity and temperature logger
CTD = Conductivity, temperature, depth sensor
FL = Fluorometer
NAS = in-situ nutrient analyser
OBS = Optical Backscatter Turbidity meter
OXY = Oxygen sensor
PAR = PAR sensor
T = Temperature logger
TR = Transmissometer
WMS = Automatic water sampler

Other Series linked to this Fixed Station for this cruise - 646170 646182 646305

Other Cruises linked to this Fixed Station (with the number of series) - PD01/08 (16) PD02/03 (4) PD02/05 (3) PD02/07 (14) PD02/09B (16) PD02/10 (9) PD05/10 (10) PD06/07 (15) PD07/08 (14) PD09/06 (11) PD09/07 (63) PD09/08 (15) PD10/03 (3) PD10/10 (8) PD11/05 (1) PD11/11 (48) PD12/05 (2) PD12/09 (10) PD13/07 (13) PD14/08 (67) PD16/06 (8) PD16/07 (14) PD17/03 (4) PD17/10 (9) PD18/04 (5) PD18/05 (3) PD18/09 (11) PD19/08 (2) PD20/02 (5) PD20/06 (8) PD20/07 (16) PD21/05 (3) PD21/10 (9) PD22/04 (5) PD22/06 (8) PD23/03A (4) PD23/07 (15) PD23/08 (12) PD24/02 (1) PD24/09 (11) PD25/03B (3) PD25/05 (3) PD25/06 (8) PD25/11 (4) PD27/07 (16) PD29/04 (4) PD29/06 (8) PD29/08 (13) PD29/10 (11) PD30/05 (2) PD31/02 (4) PD31/03 (4) PD32/04 (4) PD33/08 (4) PD33/09 (10) PD34/03 (4) PD34/05 (9) PD35/02 (4) PD35/06 (13) PD36/10 (10) PD37/06 (13) PD37/08 (17) PD38/03 (5) PD38/04 (4) PD38/09 (10) PD41/05 (10) PD43/11 (3) PD47/09 (9) PD48/05 (10) PD49/10 (7)

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