Metadata Report for BODC Series Reference Number 701858


Metadata Summary

Data Description

Data Category Hydrography time series at depth
Instrument Type
NameCategories
Sea-Bird SBE 37-IM MicroCAT C-T Sensor  water temperature sensor; salinity sensor
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 POL930B/MC2506
BODC Series Reference 701858
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2005-06-16 08:30
End Time (yyyy-mm-dd hh:mm) 2005-07-14 07:20
Nominal Cycle Interval 600.0 seconds
 

Spatial Co-ordinates

Latitude 53.45117 N ( 53° 27.1' N )
Longitude 3.64817 W ( 3° 38.9' W )
Positional Uncertainty 0.0 to 0.01 n.miles
Minimum Sensor Depth 5.0 m
Maximum Sensor Depth 5.0 m
Minimum Sensor Height 21.2 m
Maximum Sensor Height 21.2 m
Sea Floor Depth 26.2 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
PREXPR01 1 Decibars MeasPress_MW Pressure (measured variable) exerted by the water body by semi-fixed in-situ pressure sensor and corrected to read zero at sea level
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

Originator's quality control comments for PD21_05 COBS moorings

Data supplied to BODC were accompanied by data quality notes from the Originator that detailed observations made when the data were processed and subsequent processing decisions. A summary of these notes have been provided in the tables below.

Rig#928

Instrument Serial number Instrument depth Data quality comments
Sea-Bird MicroCAT 02081 5 m Comparisons performed against CTD data suggest a possible drift in temperature and conductivity towards mooring recovery, however as the data from this instrument are consistent with data from other instruments present at this site, no adjustments have been made to the data.
Aanderaa RCM 10526 10 m CTD comparison checks led to the Originator converting all conductivity cycles recorded after 2005-06-23 12:05:00 UTC into absent data values. Spikes present at cycles 675, 949-950 and 952-954 have also been converted into absent values in the conductivity channel. After comparing these data against the other instruments at this site, an offset correction of -0.02°C has been applied to the temperature channel.

Rig#929


Instrument Serial number Instrument depth Data quality comments
Sea-Bird 16+ SEACAT fitted with Seapoint Turbidity Meter 10471 04597 Located on seabed The data from this sensor are of good quality. There is a possible drift in conductivity at recovery, but as there is a good match between data from this instrument and CTD data at mooring deployment, no adjustments have been made to these data.
Teledyne RDI 600 kHz ADCP 3644 Located on seabed To correct for the magnetic declination (difference between magnetic north and true north) latitude values were changed by -4.0033°. All latitude values were modified by +1.3348° to correct for the compass error.

Rig#930


Instrument Serial number Instrument depth Data quality comments
Sea-Bird MicroCAT 02506 5 m Comparisons performed against CTD data at mooring deployment and recovery found no offset in temperature at deployment, however the values had drifted by mooring recovery. There was an offset of -0.0070 S m-1in conductivity at mooring deployment, and the conductivity had drifted even further away from the values recorded by the CTD by mooring recovery. The conductivity channel has been adjusted by the minimum offset observed in this series, leading to an offset correction of +0.0070 S m-1 being applied.
Aanderaa RCM 09959 10 m The Originator recommends that the data from this instrument are not used, as the data are of poor quality.

Rig#931


Instrument Serial number Instrument depth Data quality comments
Sea-Bird 16+ SEACAT fitted with Seapoint Turbidity Meter 10489 04737 Located on seabed Good quality temperature data were recorded by this instrument. Deployment CTD checks revealed an offset of -0.0054 S m-1 in conductivity, as well as a slight drift towards recovery. An offset correction of +0.0054 S m-1 has been applied to these data.
Teledyne RDI 600 kHz ADCP 2391 Located on seabed To correct for the magnetic declination (difference between magnetic north and true north) latitude values were changed by -4.1164°. All latitude values were modified by -6.1267° to correct for the compass error.

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

Sea-Bird SBE37-IM MicroCAT

The SBE 37-IM MicroCAT is a high accuracy conductivity and temperature recorder (pressure optional) with a built in Inductive Modem, which provides reliable, low-cost, real-time data transmission. Designed for moorings and other long-duration, fixed-site deployments, MicroCATs have non-corroding titanium housings rated for operation to 7000 metres or pressure sensor full scale-range.

Communication with the MicroCAT is via a Surface Inductive Modem (SIM) to a computer or data logger. Commands and data are transmitted half-duplex between the SIM and the MicroCAT using DPSK (differential-phase-shift-keyed) telemetry. As a safe guard, the MicroCAT simultaneously backs up the data in its non-volatile internal memory as well as transmitting the data via telemetry.

The MicroCAT's aged and pressure-protected thermistor has a long history of exceptional accuracy and stability (typical drift is less than 0.002 °C per year). Electrical isolation of the conductivity electronics eliminates any possibility of ground-loop noise.

Specifications

  Temperature
(°C)
Conductivity (S m -1 ) Optional Pressure
Measurement Range -5 to +35 0 to 7 (0 to 70 mS cm -1 ) 0 to full scale range: 20 / 100 / 350 / 600 / 1000 / 2000 / 3500 / 7000 metres
Initial accuracy 0.002 0.0003 0.1% of full scale range
Typical Stability 0.0002 per month 0.0003 per month 0.05% of full scale range per year
Resolution 0.0001 0.00001 0.002% of full scale range
Sensor Calibration +1 to +32 0 to 6; physical calibration over range 2.6 to 6 S m -1 , plus zero conductivity (air) Ambient pressure to full scale range in 5 steps
Memory 8 Mbyte non-volatile FLASH memory
Data Storage Converted temperature and conductivity: 5 bytes per sample (2.5 bytes each)
Time: 4 bytes per sample
Pressure (optional): 2 bytes per sample
Real-Time Clock 32,768 Hz TCXO accurate to ±1 minutes year -1
Standard Internal Batteries 10.6 Ampere-hour pack consisting of 12 AA lithium batteries. Provides sufficient capacity for more than 200,000 samples for a typical sampling scheme
Housing Titanium pressure case rated at 7000 metres
Weight (without pressure) In water: 2.4 kg
In air: 4.0 kg

Further information can be found via the following link: Sea-Bird SBE37-IM MicroCAT Datasheet

Processing of Seabird MicroCAT data by BODC

The data were provided to BODC in ASCII format, and the series were reformatted into BODC standard internal format using a transfer function. The following table shows how the Originator's variables present in the Sea-Bird MicroCAT data were mapped to the appropriate BODC parameter codes.

Originator's variable Units Description BODC parameter code Units Comments
Date/Time yyyy mm dd hh mm ss - - - This variable was not transferred. BODC re-calculate date and time during the transfer process
Temperature Deg(C) Temperature of the water body TEMPPR01 °C -
Conductivity S m -1 Electrical conductivity of the water body by in-situ conductivity cell CNDCPR01 S m -1 -
Pressure dbar Pressure (measured variable) exerted by the water body by fixed in-situ pressure sensor and corrected to read zero at sea level PREXPS01 db -
Salinity No units provided Practical salinity of the water body by conductivity cell and computation using UNESCO 1983 algorithm PSALPR01 Dimensionless This was supplied by the Originator and calculated following Fofonoff and Millard (1983).

The reformatted data were visualised using the in-house EDSERPLO software. Suspect data were marked by adding an appropriate quality control flag, missing data by both setting the data to an appropriate value and setting the quality control flag. Any channels which comprised entirely of absent data indicators were excluded from the final qxf.

References

Fofonoff, NP and Millard, RC. 1983. Algorithms for computations of fundamental properties of seawater. UNESCO Technical Papers in Marine Science, 44, p.53.

SeaBird MicroCAT Data Processing

Data Originator's Processing

After the mooring was recovered, the data were downloaded from the instrument logger, and factory calibrations were applied to the conductivity, temperature and pressure channels, when present.

Before the data were supplied to BODC, basic quality control was performed by the Data Originator. The first stage of quality checks involved comparing the data from each instrument with CTD measurements recorded during the deployment and recovery of the mooring. Following the comparison against CTD data secondary checks were performed by comparing the data from each instrument against the data from other sensors attached to that mooring. The Originator has provided BODC with a document containing a full description of their quality control methodology . Depending on the result of the quality checks for each series, one of the following actions was performed by the Originator:

A full description of the results of these quality checks can be found in the relevant Originator's data processing comments document.

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) 2005-06-16
End Date (yyyy-mm-dd) 2005-07-14
Organization Undertaking ActivityProudman Oceanographic Laboratory (now National Oceanography Centre, Liverpool)
Country of OrganizationUnited Kingdom
Originator's Data Activity IdentifierPOLRIG930
Platform Categorymoored surface buoy

Smartbuoy deployment LB2_002 / POLRIG#930

Deployment and Recovery

This rig was deployed as part of the Liverpool Bay Coastal Observatory during R.V. Prince Madog cruise PD21_05. Conditions during deployment were good, the sea state was slight, with winds weakening from the south. Recovery of the rig took place during R.V. Prince Madog cruise PD25_05. Conditions were good, the sea state had a slight swell from the NW, with NW winds force 1 - 2.

Rig Position 53 27.072N, 3 38.887W
Water Depth 26.2
Deployed 16 June 2005 08:28:00 GMT
Recovered 14 July 2005 07:23:00 GMT
No. of Days 28

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.

The CEFAS SmartBuoy is fitted with a surface CTD (including turbidity and 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 2245 Chlorophyll
Fluorescence
1 28
Falmouth Scientific OEM CT sensor 1401 Temperature
Conductivity
(Salinity Derived)
1 28
Seapoint Turbidity meter 1550 Turbidity 1 28
Druck 5 bar Pressure Transducer 1220412 Pressure (ADCP and telemetry) 1 No information available
Analog Devices Roll / Pitch 28 Roll
Pitch
1 No information available
Battery Monitor 28 Battery 1 No information available

Stand Alone Sensors

Instrument Serial
Number
Parameters Meter
depth (m)
Record
Length (days)
WMS-1 Aqua Monitor 2255 Silicate
Suspended Load
Total Oxidised Nitrogen
1 14

The table below details the POL instrumentation
Instrument Serial Number DSU Number Meter Level Parameters Measured Sampling Interval Comments
Sea-Bird MicroCAT SBE37-IM V2.1 2506 - 5m below surface Temperature
Conductivity
10 minutes Upon recovery the clock was found to be running 5 s fast.
Aanderaa current meter RCM7 9959 8123 10 m below surface Temperature
Conductivity
Pressure
10 minutes Instrument malfunctioning; see problem report.
No fin; used only to log temperature (low temperature setting) and conductivity.

DSU = Data Storage Unit

Other Series linked to this Data Activity - 1195180 1195179 1195192 1195167 701729

Cruise

Cruise Name PD21/05
Departure Date 2005-06-15
Arrival Date 2005-06-17
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 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 - 701729 701914 1195167 1195179 1195180 1195192 1622755

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) PD18/05 (8) PD18/09 (10) PD19/08 (2) PD20/06 (4) PD20/07 (7) 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