Metadata Report for BODC Series Reference Number 888193


Metadata Summary

Data Description

Data Category CTD or STD cast
Instrument Type
NameCategories
Sea-Bird SBE 911 CTD  CTD; water temperature sensor; salinity sensor
Instrument Mounting lowered unmanned submersible
Originating Country Ireland
Originator Dr Martin White
Originating Organization National University of Ireland, Galway
Processing Status banked
Project(s) Oceans 2025
Porcupine Abyssal Plain (PAP)
Oceans 2025 Theme 2
Oceans 2025 Theme 2 WP2.5
 

Data Identifiers

Originator's Identifier CE0716_10
BODC Series Reference 888193
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2007-06-23 03:44
End Time (yyyy-mm-dd hh:mm) 2007-06-23 04:45
Nominal Cycle Interval 1.0 decibars
 

Spatial Co-ordinates

Latitude 48.91650 N ( 48° 55.0' N )
Longitude 16.50020 W ( 16° 30.0' W )
Positional Uncertainty Unspecified
Minimum Sensor Depth 5.0 m
Maximum Sensor Depth 2537.0 m
Minimum Sensor Height 2303.0 m
Maximum Sensor Height 4835.0 m
Sea Floor Depth 4840.0 m
Sensor Distribution Variable common depth - All sensors are grouped effectively at the same depth, but this depth varies significantly during 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
ACYCAA01 1 Dimensionless Record_No Sequence number
PRESPR01 1 Decibars Pres_Z Pressure (spatial co-ordinate) exerted by the water body by profiling pressure sensor and corrected to read zero at sea level
PSALCU01 1 Dimensionless P_sal_CTD_uncalib Practical salinity of the water body by CTD and computation using UNESCO 1983 algorithm and NO calibration against independent measurements
SIGTEQST 1 Kilograms per cubic metre Sigma-T Sigma-T of the water body by computation from salinity and temperature using UNESCO 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

Instrument Description

CTD Unit and Auxiliary Sensors

Instrument Manufacturer Model Serial number Last calibration date Comments
CTD SeaBird SBE 911plus CTD - - -
Temperature sensor SeaBird SBE 3plus 4023 19 th January 2006 -
Conductivity sensor SeaBird SBE 4C 2796 18 th January 2006 -
Pressure sensor Paroscientific Digiquartz 88906 25 th January 2002 -
24 Bottle Rosette SeaBird - - - -

See the Cruise Report for more details on the sensors.

Sea-Bird Electronics SBE 911 and SBE 917 series CTD profilers

The SBE 911 and SBE 917 series of conductivity-temperature-depth (CTD) units are used to collect hydrographic profiles, including temperature, conductivity and pressure as standard. Each profiler consists of an underwater unit and deck unit or SEARAM. Auxiliary sensors, such as fluorometers, dissolved oxygen sensors and transmissometers, and carousel water samplers are commonly added to the underwater unit.

Underwater unit

The CTD underwater unit (SBE 9 or SBE 9 plus ) comprises a protective cage (usually with a carousel water sampler), including a main pressure housing containing power supplies, acquisition electronics, telemetry circuitry, and a suite of modular sensors. The original SBE 9 incorporated Sea-Bird's standard modular SBE 3 temperature sensor and SBE 4 conductivity sensor, and a Paroscientific Digiquartz pressure sensor. The conductivity cell was connected to a pump-fed plastic tubing circuit that could include auxiliary sensors. Each SBE 9 unit was custom built to individual specification. The SBE 9 was replaced in 1997 by an off-the-shelf version, termed the SBE 9 plus , that incorporated the SBE 3 plus (or SBE 3P) temperature sensor, SBE 4C conductivity sensor and a Paroscientific Digiquartz pressure sensor. Sensors could be connected to a pump-fed plastic tubing circuit or stand-alone.

Temperature, conductivity and pressure sensors

The conductivity, temperature, and pressure sensors supplied with Sea-Bird CTD systems have outputs in the form of variable frequencies, which are measured using high-speed parallel counters. The resulting count totals are converted to numeric representations of the original frequencies, which bear a direct relationship to temperature, conductivity or pressure. Sampling frequencies for these sensors are typically set at 24 Hz.

The temperature sensing element is a glass-coated thermistor bead, pressure-protected inside a stainless steel tube, while the conductivity sensing element is a cylindrical, flow-through, borosilicate glass cell with three internal platinum electrodes. Thermistor resistance or conductivity cell resistance, respectively, is the controlling element in an optimized Wien Bridge oscillator circuit, which produces a frequency output that can be converted to a temperature or conductivity reading. These sensors are available with depth ratings of 6800 m (aluminium housing) or 10500 m (titanium housing). The Paroscientific Digiquartz pressure sensor comprises a quartz crystal resonator that responds to pressure-induced stress, and temperature is measured for thermal compensation of the calculated pressure.

Additional sensors

Optional sensors for dissolved oxygen, pH, light transmission, fluorescence and others do not require the very high levels of resolution needed in the primary CTD channels, nor do these sensors generally offer variable frequency outputs. Accordingly, signals from the auxiliary sensors are acquired using a conventional voltage-input multiplexed A/D converter (optional). Some Sea-Bird CTDs use a strain gauge pressure sensor (Senso-Metrics) in which case their pressure output data is in the same form as that from the auxiliary sensors as described above.

Deck unit or SEARAM

Each underwater unit is connected to a power supply and data logging system: the SBE 11 (or SBE 11 plus ) deck unit allows real-time interfacing between the deck and the underwater unit via a conductive wire, while the submersible SBE 17 (or SBE 17 plus ) SEARAM plugs directly into the underwater unit and data are downloaded on recovery of the CTD. The combination of SBE 9 and SBE 17 or SBE 11 are termed SBE 917 or SBE 911, respectively, while the combinations of SBE 9 plus and SBE 17 plus or SBE 11 plus are termed SBE 917 plus or SBE 911 plus .

Specifications

Specifications for the SBE 9 plus underwater unit are listed below:

Parameter Range Initial accuracy Resolution at 24 Hz Response time
Temperature -5 to 35°C 0.001°C 0.0002°C 0.065 sec
Conductivity 0 to 7 S m -1 0.0003 S m -1 0.00004 S m -1 0.065 sec (pumped)
Pressure 0 to full scale (1400, 2000, 4200, 6800 or 10500 m) 0.015% of full scale 0.001% of full scale 0.015 sec

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

BODC Processing

The data arrived at BODC in 11 Ascii files, representing eleven of the twelve CTD casts taken during the cruise. One of the ctd files had been accidentally overwritten on board the ship thus was unavailable for archiving. These eleven files were reformatted to the internal QXF format using BODC transfer function 401. The following table shows how the variables were mapped to the appropriate BODC parameter codes.

Originator's variable Units Description BODC Parameter code Units Comments
Pressure dbar Pressure exerted by the water column by profiling pressure sensor. PRESPR01 dbar -
Temperature °C Temperature of the water column TEMPPR01 °C -
Salinity psu Practical salinity of the water column PSALCU01 psu -
Density kg m -3 Sigma-T of the water column by computation
from salinity and temperature.
SIGTEQST kg m -3 Sigma-T is rederived during the BODC Transfer process.

The reformatted data were visualised using the in-house EDSERPLO software. Suspect data were marked by adding an appropriate quality control flag.

BODC also hold original SeaBird files of this data, which are available on request.

Originator's Data Processing

Sampling Strategy

A total of twelve CTD stations were completed during CE0716, four deep casts for both SBE Microcat calibration and acoustic release tests, three to 2500m in a triangle around the PAP site and 5 in support of near surface bottle sample measurements.

Station number Date and Time Latitude Longitude CTD depth Comments
001 21/6/07 10:38 48°59.94' N 16°30.12' W 3215m CTD cast to calibrate Microcats
002 21/6/07 13:51 48°59.95' N 16°30.12' W 268m CTD cast to support near surface bottle measurements
CTD cast alongside Wetlabs and ISUS to 300m
003 21/6/07 14:51 48°59.95' N 16°30.11' W 4730m CTD cast to calibrate Microcats
CTD to test wire releases to 5000m
004 21/6/07 18:24 48°59.95' N 16°30.12' W 304m CTD cast to support near surface bottle measurements
005 21/6/07 19:44 48°59.95' N 16°30.11' W 41m CTD cast to support near surface bottle measurements
006 21/6/07 20:03 48°59.95' N 16°30.12' W 4715m CTD cast to calibrate Microcats
007 22/6/07 12:27 49°00.13' N 16°27.27' W 470m CTD cast to support near surface bottle measurements
008 22/6/07 20.29 49°05.09' N 16°24.06' W 2508m CTD close to PAP site
009 23/6/07 01:04 48°54.99' N 16°18.00' W 2536m CTD close to PAP site
010 23/6/07 03:44 48°54.99' N 16°30.01' W 2537m CTD close to PAP site
011 23/6/07 07:15 48°59.16' N 16°25.05' W 40m CTD cast to estimate DCM for snatcher
Data not available, cast overwritten by cast 12 on board ship.
012 23/6/07 15:27 48°58.60' N 16°30.70' W 4766m CTD cast to calibrate Microcats

Data Processing

During the first CTD profile, a problem became apparent when unrealistic temperature and salinity values were registered, most notably in salinity. The sensor was changed and at the second attempt values were still not realistic. Subsequent investigations revealed that incorrect calibration coefficients for the temperature had been input into the CTD configuration file prior to the survey. These coefficients were corrected and the CTD performed well thereafter. The raw data were re-processed post-cruise to obtain the correct calibration data for the Microcats.

An initial view of the CTD data on-board revealed that it was clean with no obvious irregularities in any measurements.

The data were processed by Martin White, University of Ireland, Galway, using his own routines, rather than the SeaBird software. The temperature and conductivity data were run through a 121 point median filter (about 5 seconds in time) before salinity was calculated. Then the salinity was run through the same filter before density was calculated.

Then the equivalent of loop edit was run before the 1 db averages were calculated.

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

Oceans 2025 - The NERC Marine Centres' Strategic Research Programme 2007-2012

Who funds the programme?

The Natural Environment Research Council (NERC) funds the Oceans 2025 programme, which was originally planned in the context of NERC's 2002-2007 strategy and later realigned to NERC's subsequent strategy (Next Generation Science for Planet Earth; NERC 2007).

Who is involved in the programme?

The Oceans 2025 programme was designed by and is to be implemented through seven leading UK marine centres. The marine centres work together in coordination and are also supported by cooperation and input from government bodies, universities and other partners. The seven marine centres are:

Oceans2025 provides funding to three national marine facilities, which provide services to the wider UK marine community, in addition to the Oceans 2025 community. These facilities are:

The NERC-run Strategic Ocean Funding Initiative (SOFI) provides additional support to the programme by funding additional research projects and studentships that closely complement the Oceans 2025 programme, primarily through universities.

What is the programme about?

Oceans 2025 sets out to address some key challenges that face the UK as a result of a changing marine environment. The research funded through the programme sets out to increase understanding of the size, nature and impacts of these changes, with the aim to:

In order to address these aims there are nine science themes supported by the Oceans 2025 programme:

In the original programme proposal there was a theme on health and human impacts (Theme 7). The elements of this Theme have subsequently been included in Themes 3 and 9.

When is the programme active?

The programme started in April 2007 with funding for 5 years.

Brief summary of the programme fieldwork/data

Programme fieldwork and data collection are to be achieved through:

The data is to be fed into models for validation and future projections. Greater detail can be found in the Theme documents.


Porcupine Abyssal Plain (PAP) Observatory

Scientific Rationale

During the past decade, the intention has been to observe changes in rate and state variables within the entire water column and benthos, for a wide range of biogeochemically significant features in the centre of the Porcupine Abyssal Plain. The site appears to satisfy many of the conditions for simplicity; it lies well away from regions where physical gradients are strong and is in the middle of one of the biogeochemical provinces. The seabed is very flat over large areas (4800m depth) and there is no evidence of significant advective supply of material. Below the upper mixed layer, currents are generally northerly and of low velocity. The depth of winter mixing is large and variable (300-800m) and this facilitates research into the effects of the most important driving force on upper ocean biogeochemistry: nutrient supply. There is a substantial data base from previous programs on which to build: the PAP site is about 350Km to the northeast of the site of the JGOFS North Atlantic Bloom Experiment in 1989 (see Deep Sea Research volume 40 1-2) and the continuing work by IFM, Kiel. It was the focus of the EU BENGAL program from 1998-2001 (See Progress in Oceanography volume 50 1-4) and is at the northern boundary of the French POMME program. Ships of opportunity contribute significantly with frequent transects by the Continuous Plankton Recorder since 1949 and PCO2 transects under the EU program CAVASSOO. It was a focus of the then SOC Deacon Divison core research program BICEP which draws the link between upper ocean processes and the deep ocean benthos where there has been a major biological regime shift in the mid 1990's.

At the beginning of the project in 2002, three moorings were deployed at the PAP site with the intention of recovering and redeploying each of them annually.

The three moorings deployed comprised the following:

References

Billett, D.S.M., Bett B.J., Reid, W.D.K., Boorman, B. and Priede, M. Long-term change in the abyssal NE Atlantic: The 'Amperima Event' revisited. Deep Sea Research II; PAP special volume (Submitted)

Hartman. S., Larkin. K. E., Lampitt, R. S, Koeve, W., Yool, A., Körtzinger, A., Hydes, D.J. (This volume) Seasonal and inter-annual biogeochemical variations at PAP (49°N, 16.5°W) 2003-2005. Deep Sea Research II; PAP special volume (Submitted)

Gooday, A et al. Long term change in foraminiferans Deep Sea Research II, PAP special volume (Submitted)

Martin, A.P., Lucas, M.I., Painter, S.C., Pidcock, R., Prandke H., Prandke,H., Stinchcombe, M.C. (2008) The supply of nutrients due to vertical turbulent mixing: a study at the Porcupine Abyssal Plain study site (49°50'N 16°30'W) in the northeast Atlantic. Deep Sea Research II, PAP special volume (Submitted)


Oceans 2025 Theme 2: Marine Biogeochemical Cycles

Marine biogeochemical cycles are the key processes that control the cycling of climate-active gases within the surface ocean; the main transport mechanisms governing the supply of nutrients from deeper waters across the pycnocline; and the flux of material to deep water via the biological carbon pump. The broad aim of this Theme is to improve knowledge of major biogeochemical processes in the surface layer of the Atlantic Ocean and UK shelf seas in order to develop accurate models of these systems. This strategic research will result in predictions of how the ocean will respond to, and either ameliorate or worsen, climate change and ocean acidification.

Theme 2 comprises three Research Units and ten Work Packages. Theme 2 addresses the following pivotal biogeochemical pathways and processes:

The official Oceans 2025 documentation for this Theme can be found using the following link: Oceans 2025 Theme 2


Oceans 2025 Theme 2, Work Package 2.5: Physical Processes and the Supply of Nutrients to the Euphotic Zone

The emphasis behind this Work Package is to gain a better understanding of the ocean's biological carbon pump (OBP), an important process in the global carbon cycle. Small changes in its magnitude resulting from climate change could have significant effects, both on the ocean's ability to sequester CO2 and on the natural flux of marine carbon. This work package is concerned with the effect of physical processes and circulation on nutrient supply to the euphotic zone. Many physical pathways influence nutrient supply, such as winter overturning, Ekman pumping, small-scale turbulent mixing and mesoscale ageostrophic circulations, (of which, eddy pumping is but one example). Increased stratification will change patterns of winter overturning and dampen small-scale mixing. Shifts in wind patterns will perturb Ekman pumping. Changes in gradients of ocean heating and wind-forcing will alter the distribution of potential energy released through baroclinic instability of eddies and fronts. The combined effect of change on total nutrient supply will therefore be complex. Such physically-mediated changes, coupled to changes in aeolian dust deposition, may profoundly alter upper ocean plankton communities, biogeochemical cycling and carbon export.

This Work Package will be primarily coordinated by the National Oceanography Centre, Southampton (NOC). Specific objectives are:

Aspects of this work will link to Oceans 2025 Theme 9 and 10, and Theme 2 WP 2.6.

More detailed information on this Work Package is available from pages 13-15 of the official Oceans 2025 Theme 2 document: Oceans 2025 Theme 2

Weblink: http://www.oceans2025.org/


Data Activity or Cruise Information

Cruise

Cruise Name CE0716
Departure Date 2007-06-19
Arrival Date 2007-06-25
Principal Scientist(s)Richard Stephen Lampitt (National Oceanography Centre, Southampton)
Ship Celtic Explorer

Complete Cruise Metadata Report is available here


Fixed Station Information

Fixed Station Information

Station NamePorcupine Abyssal Plain (PAP)
CategoryOffshore location
Latitude49° 0.00' N
Longitude16° 30.00' W
Water depth below MSL4800.0 m

Porcupine Abyssal Plain (PAP) Observatory

The Porcupine Abyssal Plain (PAP) observatory is a site at which moorings were deployed in the Northeastern Atlantic, as part of the ANIMATE (Atlantic Network of Interdisciplinary Moorings and Time-series for Europe), MERSEA (Marine Environment and Security for the European Area) and then EuroSITES projects. The PAP site is centred at latitude 49° N and longitude 16.5° W. Moorings have occupied this region since 2002 and are typically deployed for 12 months.

Data summary

Mooring deployment Temperature salinity pressure ADCP Chlorophyll Sediment trap Current meter Nitrate Carbon dioxide Oxygen Irradience
Real time Delayed mode Real time Delayed mode Real time Delayed mode Real time Delayed mode Real time Delayed mode Real time Delayed mode Real time Delayed mode
PAP1 Oct 2002-Jun 2003 Data Data Data NT UD Data - Data NT Data NT SF - - - -
PAP2 Jul 2003-Nov 2003 CF Data Data NT Data Data - Data NT Data NT Data - - - -
PAP3 Nov 2003-Jun 2004 Data Data Data NT Data Data - Data NT Data NT Data - - - -
PAP4 Jun 2004-Jul 2005 Data Data Data NT Data Data - Data NT UD NT Data - - - -
PAP5 Jul 2005-Jun 2006 Data Lost Lost NT Lost Data - Data NT Lost NT Lost - - - -
PAP6 Jul 2006-Jul 2007 ND ND ND ND ND Data - Data ND ND ND ND - - - -
PAP7 Jun 2007-Aug 2007 Data Lost ND Data Data NYR - NYR SF SF NT Data - - - -
PAP 200905 May 2009-Jul 2009 Data Data - Data Data - - - Data Data SF SF - Data - -
PAP 201005 May 2010- Data - - Data - - Data - Data - Data - Data - Data -

Status Indicators

Indicator Description
Data Data received from mooring
Lost Data not received
SF Sensor failed
ND Not deployed
NYR Not yet recovered
CF Communications failure
UD Unusable data
NT Not telemetered

Other Series linked to this Fixed Station for this cruise - 888088 888107 888119 888120 888132 888144 888156 888168 888181 888200 945170 1058137 1083405 1225804 1225816 1225828 1225841 1225853 1225865 1225877 1225889 1225890 1225908 1225921 1225933

Other Cruises linked to this Fixed Station (with the number of series) - CD158 (13) D266 (11) D341 (35) JC034T (4) JC071 (2) JC085 (9) M108 (1) PO300_1 (12) PO306 (14)


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