Metadata Report for BODC Series Reference Number 1204676

Metadata Summary
Problem Reports
Data Access Policy
Narrative Documents
Project Information
Data Activity or Cruise Information
Fixed Station Information
BODC Quality Flags
SeaDataNet Quality Flags

Metadata Summary

Data Description

Data Category

Hydrography time series at depth

Instrument Type

Name	Categories
Hydrolabs Series 5 probes	sea level recorders; fluorometers; radiometers; optical backscatter sensors; water temperature sensor; nutrient analysers; salinity sensor; dissolved gas sensors; pH sensors; redox potential sensors

Instrument Mounting

null

Originating Country

United Kingdom

Originator

Dr Matthew Blackburn

Originating Organization

Scottish Environment Protection Agency, Edinburgh

Processing Status

banked

Online delivery of data

Download available - Ocean Data View (ODV) format

Project(s)

Data Identifiers

Originator's Identifier	SEPA_SOUTH_ALLOA_BODC_1998_GMT/980609
BODC Series Reference	1204676

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm)	1998-06-09 15:30
End Time (yyyy-mm-dd hh:mm)	1998-06-26 14:00
Nominal Cycle Interval	900.0 seconds

Spatial Co-ordinates

Latitude	56.10285 N ( 56° 6.2' N )
Longitude	3.80987 W ( 3° 48.6' W )
Positional Uncertainty	0.0 to 0.01 n.miles
Minimum Sensor or Sampling Depth	0.5 m
Maximum Sensor or Sampling Depth	0.5 m
Minimum Sensor or Sampling Height	4.5 m
Maximum Sensor or Sampling Height	4.5 m
Sea Floor Depth	5.0 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	Approximate - Depth is only approximate
Sea Floor Depth Datum	Approximate - Depth is only approximate

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
OXYSZZ01	1	Percent	Saturation of oxygen {O2 CAS 7782-44-7} in the water body [dissolved plus reactive particulate phase]
PHXXZZXX	1	pH units	pH (unspecified scale) of the water body
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

Alloa Quality Report

Screening and QC

The data have had QC applied by SEPA with suspect data being removed. Data then went through BODC QC procedures.

During screening noisy periods were observed in several parameters, but these were left unflagged. M flags were applied to spikes and to slightly negative values in TURBXXXX, ODSDM021 and CPHLZZXX. In the TURBXXXX and CPHLZZXX channels there were also negative vlaues which where less than -1 NTU and -1 mg m^-3 respectively that were flagged null. These values are available on request. Null values were assigned an N flag.

Prolonged periods with constant data were also considered anomalous and flagged, these can be identified for TEMPPR01 in a number of series including 1205004 and 1205028. Several series also exhibit anomalous TEMPPR01 data which were flagged (e.g. series 1204916, 1204941, 1204953, 1204965, 1204989, 1205028, 1205053, 1205065).

A period with anomalous DOXYSZZ01, PHXXZXX and PSALZZXX has been identified in series 1205201 (from 18 August 2009 12:00 hours to 21 August 2009 11:00 hours). After some investigation, it was decided not to assign any quality flags as it these data were found to be related with a meteorological event. Although readings are considered to be valid, the data should be used with caution.

For some series, TURBXXXX and CPHLZZXX exhibit some high values which might be related with particles adhering to the sensor. These instances have not been flagged.

Ship service visits were taken at a single point in time, where stated in the originator's data.

Data Access Policy

Open 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.

If the Information Provider does not provide a specific attribution statement, or if you are using Information from several Information Providers and multiple attributions are not practical in your product or application, you may consider using the following:

"Contains public sector information licensed under the Open Government Licence v1.0."

Narrative Documents

Hydrolabs Series 5 parameter probe

The Hydrolabs series 5 includes multi-parameter probes that allow for optimized combinations of sensors and accessories to be used in monitoring applications in different environmental sources. The available sensors provide data for temperature, depth, conductivity, salinity, specific conductance, TDS, pH, ORP, dissolved oxygen, turbidity, chlorophyll a, blue-green algae, Rhodamine WT, ammonium, nitrate, chloride, PAR and total dissolved gases.

The various models (MS5, DS5 and DS5X) operate in a similar way and the main differences relate to the number of parameters measured, MS5 measures up to 12 parameters and DS5 and DS5X can measure up to 16 parameters simultaneously.

All models can operate in a temperature ranging from 0°C to 50°C and can be deployed at depths up to 200 m.

Below is a table with the sensors specifications:

Sensor	Range	Accuracy	Resolution
Depth	0 to 10 m 0 to 25 m 0 to 100 m 0 to 200 m	± 0.003 m ± 0.05 m ± 0.05 m ± 0.1 m	0.001 m 0.01 m 0.01 m 0.1 m
Temperature	-5° to 50°C	± 0.10°C	0.01°C
Conductivity	0 to 100 mS cm^-1	±(0.5% of reading + 0.01 mS cm^-1)	-
Salinity	0 to 70 ppt	± 0.2 ppt	0.01 ppt
pH	0 to 14	± 0.2	0.01
Turbidity (self-cleaning)	0 to 3000 NTU	Compared to StablCal ± 1% up to 100 NTU ± 3% from 100-400 NTU ± 5% from 400-3000 NTU	0.1 NTU from 0-400 NTU 1 NTU for >400-3000 NTU
Turbidity (4 Beam)	0 to 1000 NTU	± (5% of reading + 1 NTU)	0.1 NTU from 0-100 NTU 1 NTU for >100 NTU
Chlorophyll a	Dynamic range Low sensitivity: 0.03-500 µg l^-1 Med. sensitivity: 0.03-50 µg l^-1 High sensitivity: 0.03-5 µg l^-1	± 3% using Rhodamine WT dye as a standard at >= 400 ppb	0.01 µg l^-1
Hach DO	0 to 60 mg l^-1	± 0.1 mg l^-1 @ <= 8 mg l^-1 ± 0.2 mg l^-1 @ > 8 mg l^-1 ± 10% of reading > 20 mg l^-1	0.01 mg l-1
Polarographic DO	0 to 50 mg l^-1	± 0.2 mg l^-1 @ <= 20 mg l^-1 ± 0.6 mg l^-1 @ >= 20 mg l^-1	0.01 mg l^-1
Blue green algae	Dynamic range Low sensitivity: 150-210⁶ cells ml^-1 Med. sensitivity: 150-210⁵ cells ml^-1 High sensitivity: 150-2*10⁴ cells ml^-1	± 3% using Rhodamine WT dye as a standard at >= 400 ppb	20 cells ml^-1
Rhodamine WT	Dynamic range Low sensitivity: 0.04-1000 ppb Med. sensitivity: 0.04-100 ppb High sensitivity: 0.04-10 ppb	± 3% for 1 ppb Rhodamine WT or higher	0.01 ppb
Total Dissolved Gases	400 to 1400 mmHg	± 1.5 mmHg	1.0 mmHg
ORP	-999 to 999 mV	± 20 mV	1 mV
PAR	0 to 10000 µmol s^-1 ^-2	± 0.10°C	1 µmol s^-1 m^-2
Ion Selective Electrodes (max depth of 15 meters)
Ammonia	0 to 100 mg l^-1-N	> 5% of reading or ± 2 mg l^-1-N	0.01 mg l^-1-N
Nitrate	0 to 100 mg l^-1-N	> 5% of reading or ± 2 mg l^-1-N	0.01 mg l^-1-N
Chloride	0.5 to 18000 mg l^-1	> 5% of reading or ± 2 mg l^-1	4 digits

Further information can be found in the manufacturer's data sheet.

SEPA Mooring Instrumentation

The SEPA long-term monitoring project has obtained hydrographic data across various moorings through the deployment of a YSI 6600 multi-parameter-sonde attached to a fixed mooring buoy at the surface of the water column.

These mooring sites include: Dunoon, Gunnet Ledge, Inner Clyde Estuary, Campbelltown, Loch Striven, Ythan, Loch Sunart, South Alloa, and Moray Firth.

The South Alloa site had two Hydrolab MS5 probes up until the 3rd of March 2011, at which point a YSI 6600 probe was used.

The Inner Clyde Estuary site also has a probe attached approximately 1 m from the sea floor in addition to the probe at the surface.

The Moray Firth site was monitored solely between July and December 2018.

The depth of the sensors at the time of measurement at each site is available upon request for the 2016 and 2017 data.

The turbidity sensors are deemed, by the manufacturer, to be used as guidance in events such as observing storm events or spotting discharges. SEPA rely on a suspended solids laboratory procedure for their turbidity reported data. The same situation occurs for chlorophyll, SEPA have a lab method they use to report it as high turbidity can interfere with the readings. This is not generally an issue in low turbidity areas.

BODC image

BODC processing of SEPA's long-term monitoring buoys

Data Acquisition and Transfer

The data were sent by SEPA as yearly .csv files and following BODC's procedures the files were checked for consistency and subsequently archived.

The data were reformatted to QXF format using BODC's established procedures. During the transfer process each yearly file was split into cruise-to-cruise series events. The table below shows how the originator's parameters were mapped to BODC parameters and their units:

Originator's Parameter	Originator's Units	BODC Parameter Code	BODC Units	Comments
Temp	deg C	TEMPPR01	°C
pH	pH Units	PHXXZZXX	pH Units
Salin	ppt	ODSDM021	ppt
DO%	% Sat	OXYSZZ01	%	For legacy data Oxygen saturation is not derived by BODC but taken from the data supplied.
DO	mg/l	DOXYZZ01	µmol/l	Conversion of * 31.252 was applied during transfer (Bittig et al., 2018)
Turb	NTU	TURBXXXX	NTU
Chl	µg/l	CPHLZZXX	mg/m³
Depth	m	PPSBPS01	m	Depth has been transferred for 2018 onwards, and is available on request for 2016 and 2017. Depth is not available for data previous to 2016.

Data Quality and Screening

Not all parameters occur in all series, particularly pH, turbidity and chlorophyll.

Oxygen saturation is not derived by BODC for consistency across all years and due to missing channels as mentioned in the originator's processing document.

The standard unit conversion factor of * 31.252 was applied to oxygen concentration during transfer to obtain the BODC units of µmol/l. (Bittig et al., 2018)

Post transfer analysis and crosschecks were applied according to BODC procedures. This involved the screening of data to check flags were appropriately applied whilst also applying further quality control flags where appropriate. Originator flags for "No sensor; Quality Control failure; Quality Control Spike Removed; Quality Control Spike removed, wiper incorrectly parking over sensor; Power Failure, Sensor failure" were all flagged as 'Null' as no data were available when these were applied.

References

Bittig, H., Körtzinger, A., Johnson, K., Claustre, H., Emerson, S., Fennel, K., ... & Xing, X. 2018. SCOR WG 142: Quality Control Procedures for Oxygen and Other Biogeochemical Sensors on Floats and Gliders. Recommendations on the conversion between oxygen quantities for Bio-Argo floats and other autonomous sensor platforms.

SEPA originator's processing document for Alloa long-term monitoring buoy

Data Acquisition and Analysis

Data were obtained from a probe attached to a mooring deployed in Firth of Forth, off Alloa. The mooring was serviced and deployed by the Scottish Environment Protection Agency (SEPA) for the purpose of long-term monitoring. Up to 3 March 2011, a Hydrolabs probe was used and subsequently replaced by a YSI 6600 probe.

The raw data were downloaded directly from the instruments, occasional problems during the remote downloading of data meant that sometimes strings were overwritten, leading to one parameter being downloaded at the expense of another. So although all parameters were measured, not all were included in the originator's files. Data were downloaded in local time and following discussion with BODC they were then corrected to GMT before being submitted.

Quality and Screening

Once downloaded the data went through SEPA data quality checks with suspect data removed and relevant flags attached to inform future users of the reason for any missing data. This information is available upon request.

Submission

The data were then submitted to BODC through ftp as yearly .csv files.

Project Information

No Project Information held for the Series

Data Activity or Cruise Information

Cruise

Cruise Name	Mi19980609
Departure Date	1998-06-09
Arrival Date	1998-06-09
Principal Scientist(s)	Matthew V Blackburn (Scottish Environment Protection Agency, Edinburgh)
Ship	Unknown self-propelled small boat

Complete Cruise Metadata Report is available here

Fixed Station Information

Station Name	SEPA_Alloa
Category	Coastal location
Latitude	56° 6.17' N
Longitude	3° 48.59' W
Water depth below MSL	5.0 m

SEPA South Alloa Fixed Station Mooring

Location Name	Alloa
Nominal Latitude (+ve N)	56.10285
Nominal Longitude (+ve E)	-3.80988
Water depth	5 m
Period of data collection	Initiated in 1988

The buoy is located in the upper Forth estuary, near Alloa, and provides measurements of dissolved oxygen, salinity, temperature, pH, chlorophyll and turbidity. Its maintenance is done on a monthly basis using one of SEPA's support vessels and is done in such a way as to prevent loss of information, for more recent records, this includes a change in the probe that is installed in the buoy, thus making readings continuous through time.

Up until July 2010, the sampling interval was set to collect a measurement every 15 minutes. From then until July 2014, a measurement was collected every 30 minutes. From this point, a sample was collected every 15 minutes. This buoy has also seen a change in the measurement probes, up to 3 March 2011, the measurements were collected with a Hydrolab Ms5, which was subsequently replaced by a YSI 6600 probe.

More information may be found at the SEPA monitoring buoy network page for Alloa.

Related Fixed Station activities are detailed in Appendix 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