Metadata Report for BODC Series Reference Number 701938

Metadata Summary

Data Description
Data Category Hydrography time series at depth
Instrument Type
NameCategories
Sea-Bird SBE 16Plus SEACAT C-T Recorder  water temperature sensor; salinity sensor
Seapoint Turbidity Meter  optical backscatter sensors
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 POL913/MX4736
BODC Series Reference 701938
 

Time Co-ordinates(UT)
Start Time (yyyy-mm-dd hh:mm) 2005-01-31 15:30
End Time (yyyy-mm-dd hh:mm) 2005-04-05 13:10
Nominal Cycle Interval 600.0 seconds
 

Spatial Co-ordinates

Latitude 53.53317 N ( 53° 32.0' N )
Longitude 3.36967 W ( 3° 22.2' W )
Positional Uncertainty 0.0 to 0.01 n.miles
Minimum Sensor Depth 26.7 m
Maximum Sensor Depth 26.7 m
Minimum Sensor Height 0.5 m
Maximum Sensor Height 0.5 m
Sea Floor Depth 27.2 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 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)
ACYCAA01 1 Dimensionless Sequence number
CNDCPR01 1 Siemens per metre Electrical conductivity of the water body by in-situ conductivity cell
CPHLPM01 1 Milligrams per cubic metre Concentration of chlorophyll-a {chl-a} per unit volume of the water body [particulate phase] by in-situ chlorophyll fluorometer and manufacturer's calibration applied
PREXPS01 1 Decibars Pressure (measured variable) exerted by the water body by fixed in-situ pressure sensor and corrected to read zero at sea level
PSALPR01 1 Dimensionless Practical salinity of the water body by conductivity cell and computation using UNESCO 1983 algorithm
TEMPPR01 1 Degrees Celsius Temperature of the water body
TURBSC01 1 Nephelometric Turbidity Units Turbidity of the water body by SCUFA turbidity meter and laboratory calibration against formazin
TURBSP01 1 Nephelometric Turbidity Units Turbidity of the water body by SeaPoint turbidity meter and laboratory calibration against formazin
 

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

Turbidity

The Sea-Bird 16plus 4737 contained two turbidity sensors, a SeaPoint s/n 10320 and a SCUFA sensor. The maximum range at which the SeaPoint sensor could record was set at 25 FTU whilst the SCUFA sensor had a larger recording range of 0 - 200 FTU. Despite this, the values recorded by the SCUFA sensor are consistently lower than those recorded by the SeaPoint sensor. Although both sensors show a similar pattern, there is a large offset present between the two sensors.

Comparisons were made between the data returned from the SeaPoint sensor with data from other SeaPoint sensors deployed concurrently at the same site and there was good agreement between the individual records, indicating that the instruments were behaving consistently. However, the signal from the SeaPoint sensor reaches saturation at times, especially in the periods between 7 February to 17 March 2005 and 25 March to 5 April 2005.

Although the data from the SeaPoint sensor follow a similar pattern to that recorded by the SCUFA sensor, due to the difference between the two sensors and the limited range at which the SeaPoint sensor records data this time series should be used with caution.

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

Sea-Bird SBE 16plus SEACAT with RS-485 Interface

The SBE 16plus is a high accuracy conductivity and temperature recorder (pressure optional). It is designed for moorings and other long-duration, fixed-site deployments. The SBE 16plus has 6 amplified A/D input channels and conditioned power of 500 ma is avaliable for auxiliary sensors, dissolved oxygen, turbidity, fluorescence, PAR etc.

Specifications

  Temperature
(°C)		 Conductivity (S m-1) Optional Pressure - strain Gauge Optional Pressure - Quartz
Measurement Range -5 to +35 0 to 9 0 to full scale range: 20 / 100 / 350 / 1000 / 1600 / 2000 / 3500 / 7000 metres 0 to full scale range: 20 / 60 / 130 / 200 / 270 / 680 / 1400 / 2000 / 4200 / 7000 / 10500 metres
Initial accuracy 0.005 0.0005 0.04% of full scale range 0.002% of full scale range
Typical Stability 0.0002 0.0003 0.1% of full scale range 0.025% of full scale range
Resolution 0.0001 0.00005 typical 0.002% of full scale range Depends on sample integration, 0.0006% of full scale range for 1 s integration
Sensor Calibration +1 to +32 0 to 9; physical calibration over range 2.6 to 6.5 S m-1 plus zero conductivity (air) Ambient pressure to full scale range in 5 steps Ambient pressure to full scale range in 5 steps
Memory 64 MB FLASH memory
Data Storage Converted temperature and conductivity: 6 bytes per sample
Time: 4 bytes per sample
Pressure (optional): 5 bytes per sample
Real-Time Clock Watch-crystal type 32,768 Hz; accuracy (±1 minutes/year)
Standard Internal Batteries 9 alkaline D-cells. Provides sufficient capacity for 145,000 samples for a CTD and 5M pump
Housing Titanium pressure case rated at 7000 metres
Weight (without pressure) In water: 8.6 kg
In air: 13.7 kg

Further information can be found via the following link: Official SBE 16plus Manual

Seapoint Turbidity Meter

The Seapoint Turbidity Meter detects light scattered by particles suspended in water, generating an output voltage proportional to turbidity or suspended solids. Range is selected by two digital lines which can be hard wired or microprocessor controlled, thereby choosing the appropriate range and resolution for measurement of extremely clean to very turbid waters. The offset voltage is within 1 mV of zero and requires no adjustment across gains. The optical design confines the sensing volume to within 5 cm of the sensor allowing near-bottom measurements and minimizing errant reflections in restricted spaces.

Sensor specifications, current at August 2006, are given in the table below.

Sensor Specifications

Power requirements 7 - 20 VDC, 3.5 mA avg., 6 mA pk.
Output 0 - 5.0 VDC
Output Time Constant 0.1 sec.
RMS Noise> < 1 mV
Power-up transient period < 1 sec.
Light Source Wavelength 880 nm
Sensing Distance (from windows) < 5 cm (approx.)
Linearity < 2% deviation 0 - 750 FTU

  Gain Sensitivity (mV FTU-1) Range (FTU)
Sensitivity/Range 100x
20x
5x
1x		 200
40
10
2		 25
125
500
**

** output is non-linear above 750 FTU.

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

SeaBird 16plus Data Processing

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 pressure, conductivity and temperature channels and to the turbidity sensor when fitted.

BODC Data Processing and Quality Control

Pressure sensors: the data record was compared with the pressure computed from the water depth on deployment and rig geometry. The time series was visually screened for evidence of rig movement (e.g. trawling) and excessive leaning (perhaps due to strong currents).

Temperature sensors: 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

Where turbidity sensors were fitted: the data record was compared with other turbidity data taken in the vicinity and checked for agreement. Obvious spikes were flagged along with any periods where the instrument became saturated (due to bio-fouling etc). Periods of excessively noisy data were noted.

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, 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) 2005-01-31
End Date (yyyy-mm-dd) 2005-04-05
Organization Undertaking ActivityProudman Oceanographic Laboratory (now National Oceanography Centre, Liverpool)
Country of OrganizationUnited Kingdom
Originator's Data Activity IdentifierPOLRIG913
Platform Categoryfixed benthic node

Proudman Oceanographic Laboratory Rig#913

Deployment and Recovery

This rig was deployed as part of the Liverpool Bay Coastal Observatory during R.V. Prince Madog cruise PD02_05. Sea conditions during deployment were rough; the tide was against the wind (force 5/6 NW) which made for difficult working conditions. As a consequence cruise objectives were severely affected by adverse weather conditions. Upon recovery superficial corrosion was noticed on the burn wire releases.

Recovery of the rig took place during R.V. Prince Madog cruise PD11_05.

Rig Position 53 31.994N, 3 22.179W
Water Depth 27.2m
Deployed 31 January 2005 15:22:00 GMT
Recovered 05 April 2005 13:17:00 GMT
No. of Days 64

Rig Description

This rig is a bottom frame comprising of the following instruments 0.5 m above the seabed; Waves Acoustic Doppler Current Profiler (ADCP) and a Sea-Bird 16plus. The frame (D2) was fitted with two Benthos releases with fizz links and a spooler with 200 m of rope for recovery of the ballast weight.


Instrument Serial Number Parameters Measured Sampling Description Comments
RDI Waves ADCP 600 kHz 5803 Horizontal current velocity components
Vertical current velocity components
Temperature
Pressure		 Mode 1: 100 pings every 10 minutes (velocity standard deviation 0.007 m s-1).
35 x 1 m bins (2.65 - 36.65 m above the bed).		 No Data due to problems with battery communications and date readings.
Sea-Bird 16plus V RS-485 1.0 4736 Temperature
Conductivity
Pressure
Turbidity
Fluorescence		 Sample interval 600 s; digiquartz integration time 40 s (Paros unit=40), 1 s delay before sampling, pump on for 0.5 s before sampling. SeaPoint turbidity sensor: S/N 10320 taped to roll bar; set up for 0 - 25 FTU range.
SCUFA Fluorimeter: Fluorescence sensor 0 - 5 V range 0 - 80 ug/l, turbidity sensor 0 - 5V range 0 - 200 FTU.
Clock set at 10:30 on 31 January 2005; delayed start at 12:00:00 on 31 January 2005. Upon recovery the clock was found to be running 33 s fast.

Cruise

Cruise Name PD02/05
Departure Date 2005-01-31
Arrival Date 2005-02-01
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 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 - 701650 701662

Other Cruises linked to this Fixed Station (with the number of series) - PD01/08 (16) PD02/03 (4) PD02/05 (2) 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 (4) 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