Metadata Report for BODC Series Reference Number 1089831


Metadata Summary

Data Description

Data Category CTD or STD cast
Instrument Type
NameCategories
Sea-Bird SBE 43 Dissolved Oxygen Sensor  dissolved gas sensors
Chelsea Technologies Group 2-pi PAR irradiance sensor  radiometers
Sea-Bird SBE 911plus CTD  CTD; water temperature sensor; salinity sensor
Paroscientific 410K Pressure Transducer  water temperature sensor; water pressure sensors
Sea-Bird SBE 3plus (SBE 3P) temperature sensor  water temperature sensor
Sea-Bird SBE 4C conductivity sensor  salinity sensor
Chelsea Technologies Group Aquatracka III fluorometer  fluorometers
Chelsea Technologies Group Alphatracka II transmissometer  transmissometers
Instrument Mounting lowered unmanned submersible
Originating Country United Kingdom
Originator Dr Andy Rees
Originating Organization Plymouth Marine Laboratory
Processing Status banked
Project(s) Oceans 2025 Theme 10 SO1:AMT
 

Data Identifiers

Originator's Identifier CTD37S
BODC Series Reference 1089831
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2010-10-26 14:09
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval 1.0 decibars
 

Spatial Co-ordinates

Latitude 22.96350 N ( 22° 57.8' N )
Longitude 40.53200 W ( 40° 31.9' W )
Positional Uncertainty 0.0 to 0.01 n.miles
Minimum Sensor Depth 1.49 m
Maximum Sensor Depth 497.74 m
Minimum Sensor Height 4902.26 m
Maximum Sensor Height 5398.51 m
Sea Floor Depth 5400.0 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
ATTNSR01 1 per metre ShortRed Attenuation (red light wavelength) per unit length of the water body by 5 or 10cm path length transmissometer
CPHLPM01 1 Milligrams per cubic metre chl-a_water_ISfluor_manufctrcal_sensor1 Concentration of chlorophyll-a {chl-a CAS 479-61-8} per unit volume of the water body [particulate >unknown phase] by in-situ chlorophyll fluorometer and manufacturer's calibration applied
CPHLPS01 1 Milligrams per cubic metre chl-a_water_ISfluor_sampcal Concentration of chlorophyll-a {chl-a CAS 479-61-8} per unit volume of the water body [particulate >unknown phase] by in-situ chlorophyll fluorometer and calibration against sample data
DOXYSC01 1 Micromoles per litre WC_dissO2_calib Concentration of oxygen {O2 CAS 7782-44-7} per unit volume of the water body [dissolved plus reactive particulate phase] by Sea-Bird SBE 43 sensor and calibration against sample data
DWIRPP01 1 Watts per square metre DWIrr_2-piPAR Downwelling 2-pi scalar irradiance as energy (PAR wavelengths) in the water body by 2-pi scalar radiometer
FVLTAQ01 1 Volts AqVolt Instrument output (voltage) by in-situ Aquatracka chlorophyll fluorometer
OXYSSC01 1 Percent BK_SBE43 Saturation of oxygen {O2 CAS 7782-44-7} in the water body [dissolved plus reactive particulate phase] by Sea-Bird SBE 43 sensor and calibration against sample data and computation from concentration using Benson and Krause algorithm
POPTSR01 1 Percent Trans_Red_10cm Transmittance (red light wavelength) per 10cm of the water body by 10cm path length red light transmissometer
POTMCV01 1 Degrees Celsius WC_Potemp Potential temperature of the water body by computation using UNESCO 1983 algorithm
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
PSALCC01 1 Dimensionless P_sal_CTD_calib Practical salinity of the water body by CTD and computation using UNESCO 1983 algorithm and calibration against independent measurements
SIGTPR01 1 Kilograms per cubic metre SigTheta Sigma-theta of the water body by CTD and computation from salinity and potential temperature using UNESCO algorithm
TEMPCU01 1 Degrees Celsius Uncal_CTD_Temp Temperature of the water body by CTD and NO verification against independent measurements
UWIRPP01 1 Watts per square metre ScalarUwirPAR Upwelling 2-pi scalar irradiance as energy (PAR wavelengths) in the water body by 2-pi scalar radiometer
 

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

Problem Report

Beam attenuance and transmissance: The majority of the transmissometer profiles are of poor quality at depth. The problem is evident on both SS and TT frame profiles although expressed slightly differently for the sensor on each rig. It appears to be a transmissometer problem related to environmental conditions such as for example where temperature or temperature gradients were beyond an acceptable threshold. The stainless steel rig mounted transmissometer displayed steps in the profile during solar noon casts only for casts 49 to 55. These steps appear when the rig was left hanging at a depth during the downcast and are likely due to the instrument cooling from the ambient on deck temperature as the profile is carried out. This effect is present on most casts for both sensors but is particularly obvious on the solar noon casts. The titanium rig mounted tranmissometer behaved suspiciously for casts 53 to 64, showing large but smooth attenuance maximum at depth as well as strong drifts. It is telling that the anomalies are not depth related but seem to be related to the depth of the thermocline i.e. these anomalies are consistently observed at the base of the strong thermocline. The anomalies observed during AMT20 are likely due to a severe case of hysteresis produced by air and water temperature in excess of the instruments operating range (1 to 25 °C). This has been observed on AMT cruises before and reported by Jeff Benson (e.g. AMT12).

The Chelsea transmissometers have been calibrated with pure water as the reference for 100% transmission and therefore beam attenuation values in clear water should be close to 0 m-1. Chelsea Instruments advise that ALPHAtracka is calibrated at the factory at 20°C in distilled water with an electrical conductivity less than one µS cm-1and filtered to better than 5 µm and that it is possible that the user will encounter water which is purer than that used during the calibration. Indeed the minimum attenuance values for the profiles from the stainless steel rig mounted tranmissometer were lower then 0 m-1 for many casts, suggesting that the calibration procedure recommended by Sea-Bird and Chelsea Instruments may need adjusting to use deep clear oceanic water as the reference for 100% transmission. The attenuance data from the transmissometers will need further offset correction to bring them in line with recognised values. Whether this should be done for the dataset as a whole or on a cast by cast basis is for the user to decide based on their requirements. The absolute attenuation values are therefore questionable but the relative profile should be reliable except for profiles where hysteresis was a problem at depth.

James Cook Cruise JC053 AMT20 CTD Data Quality Document

Chlorophyll

The sample calibrations for the fluorometers were optimised for the euphotic zone. As a result many of the calibrated chlorophyll values for the profiles below 150 - 200 dbar were slightly less than zero. All negative values were flagged as suspect. Users should therefore use caution when integrating the values over the entire profile. As the data were binned to 1 dbar some bins may have been derived by interpolation and were flagged accordingly. Where chlorophyll data values were negative the flag indicating interpolation was overwritten. The original flagged interpolated data are available on request.


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 Dissolved Oxygen Sensor SBE 43 and SBE 43F

The SBE 43 is a dissolved oxygen sensor designed for marine applications. It incorporates a high-performance Clark polarographic membrane with a pump that continuously plumbs water through it, preventing algal growth and the development of anoxic conditions when the sensor is taking measurements.

Two configurations are available: SBE 43 produces a voltage output and can be incorporated with any Sea-Bird CTD that accepts input from a 0-5 volt auxiliary sensor, while the SBE 43F produces a frequency output and can be integrated with an SBE 52-MP (Moored Profiler CTD) or used for OEM applications. The specifications below are common to both.

Specifications

Housing Plastic or titanium
Membrane

0.5 mil- fast response, typical for profile applications

1 mil- slower response, typical for moored applications

Depth rating

600 m (plastic) or 7000 m (titanium)

10500 m titanium housing available on request

Measurement range 120% of surface saturation
Initial accuracy 2% of saturation
Typical stability 0.5% per 1000 h

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

James Cook Cruise JC053 AMT20 CTD Instrumentation

Two different CTD frames were used - a stainless steel frame and a titanium frame used for trace metal sampling.

Stainless Steel

The CTD unit was a Sea-Bird Electronics 911 plus system, with dissolved oxygen sensor. The CTD was fitted with a transmissometer and a fluorometer. All instruments were attached to a stainless steel frame equipped with a Sea-Bird SBE 32 carousel. The table below lists more detailed information about the various sensors.

Sensor Model Serial Number Calibration Comments
Pressure transducer Digiquartz temperature compensated pressure sensor 110557 26/04/2009 -
Conductivity sensor 1 SBE 4C 3054 10/08/2010 -
Conductivity sensor 2 SBE 4C 3698 24/06/2010 Deployed on rig for casts 1-29
Conductivity sensor 2 SBE 4C 3580 28/07/2010 Deployed on rig for casts 30-89
Temperature sensor 1 SBE 3P 4151 01/09/2010 -
Temperature sensor 2 SBE 3P 2919 31/08/2010 -
Dissolved oxygen SBE 43 43B-0363 19/02/2009 -
Fluorometer Chelsea MkIII Aquatracka 88-2615-124 02/07/2009 Deployed on rig for casts 1-88
Fluorometer Chelsea MkIII Aquatracka 088195 08/09/2010 Deployed on rig for cast 89
PAR sensor - downwelling Chelsea PAR sensor 05 14/04/2008 -
PAR sensor - upwelling Chelsea PAR sensor 01 18/11/2008 Deployed on rig for casts 1-14
PAR sensor - upwelling Chelsea PAR sensor 06 01/10/2010 Deployed on rig for casts 15-89
Backscatter sensor WetLabs Backscatter sensor BBRTD BBRTD-759R 18/05/2010 Deployed on rig for casts 1-66
Backscatter sensor WetLabs Backscatter sensor BBRTD BBRTD-756 29/04/2010 Deployed on rig for casts 67-89
Transmissometer Chelsea MkII Alphatracka 161050 03/05/2001 0.25 m path

Change of sensors during cruise: The secondary conductivity, upwelling PAR, Wetlabs Backscatter and fluorometer sensors were changed during the cruise.

Sampling device

Rosette sampling system equipped with 24 x 20 l sampling bottles (manufactured by Ocean Test Equipment Inc.).

Titanium

The CTD unit was a Sea-Bird Electronics 911 plus system, with dissolved oxygen sensor. The CTD was fitted with a transmissometer and a fluorometer. All instruments were attached to a titanium frame equipped with a Sea-Bird SBE 32 carousel (titanium). The table below lists more detailed information about the various sensors.

Sensor Model Serial Number Calibration Comments
Pressure transducer Digiquartz temperature compensated pressure sensor 79501 22/09/2008 -
Conductivity sensor 1 SBE 4C 3567 28/07/2010 -
Conductivity sensor 2 SBE 4C 3272 27/08/2010 -
Temperature sensor 1 SBE 3P 4712 28/07/2010 -
Temperature sensor 2 SBE 3P 2729 31/08/2010 -
Dissolved oxygen SBE 43 43B-0862 10/03/2009 -
Fluorometer Chelsea MkIII Aquatracka 88-2960-160 07/10/2009 -
Backscatter sensor WetLabs Backscatter sensor BBRTD BBRTD-756 29/04/2010 -
Transmissometer Chelsea MkII Alphatracka 161048 28/05/2008 0.25 m path

Change of sensors during cruise: No instrument changes were made to the titanium rig during the cruise.

Sampling device

Rosette sampling system equipped with 24 x 10 l trace metal free sampling bottles (manufactured by Ocean Test Equipment Inc.).

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 .

Chelsea Technologies Group Aquatracka MKIII fluorometer

The Chelsea Technologies Group Aquatracka MKIII is a logarithmic response fluorometer. Filters are available to enable the instrument to measure chlorophyll, rhodamine, fluorescein and turbidity.

It uses a pulsed (5.5 Hz) xenon light source discharging along two signal paths to eliminate variations in the flashlamp intensity. The reference path measures the intensity of the light source whilst the signal path measures the intensity of the light emitted from the specimen under test. The reference signal and the emitted light signals are then applied to a ratiometric circuit. In this circuit, the ratio of returned signal to reference signal is computed and scaled logarithmically to achieve a wide dynamic range. The logarithmic conversion accuracy is maintained at better than one percent of the reading over the full output range of the instrument.

Two variants of the instrument are available, both manufactured in titanium, capable of operating in depths from shallow water down to 2000 m and 6000 m respectively. The optical characteristics of the instrument in its different detection modes are visible below:

Excitation Chlorophyll a Rhodamine Fluorescein Turbidity
Wavelength (nm) 430 500 485 440 *
Bandwidth (nm) 105 70 22 80 *
Emission Chlorophyll a Rhodamine Fluorescein Turbidity
Wavelength (nm) 685 590 530 440 *
Bandwidth (nm) 30 45 30 80 *

* The wavelengths for the turbidity filters are customer selectable but must be in the range 400 to 700 nm. The same wavelength is used in the excitation path and the emission path.

The instrument measures chlorophyll a, rhodamine and fluorescein with a concentration range of 0.01 µg l -1 to 100 µg l -1 . The concentration range for turbidity is 0.01 to 100 FTU (other wavelengths are available on request).

The instrument accuracy is ± 0.02 µg l -1 (or ± 3% of the reading, whichever is greater) for chlorophyll a, rhodamine and fluorescein. The accuracy for turbidity, over a 0 - 10 FTU range, is ± 0.02 FTU (or ± 3% of the reading, whichever is greater).

Further details are available from the Aquatracka MKIII specification sheet .

Chelsea Technologies Group ALPHAtracka and ALPHAtracka II transmissometers

The Chelsea Technologies Group ALPHA tracka (the Mark I) and its successor, the ALPHA tracka II (the Mark II), are both accurate (< 0.3 % fullscale) transmissometers that measure the beam attenuation coefficient at 660 nm. Green (565 nm), yellow (590 nm) and blue (470 nm) wavelength variants are available on special order.

The instrument consists of a Transmitter/Reference Assembly and a Detector Assembly aligned and spaced apart by an open support frame. The housing and frame are both manufactured in titanium and are pressure rated to 6000 m depth.

The Transmitter/Reference housing is sealed by an end cap. Inside the housing an LED light source emits a collimated beam through a sealed window. The Detector housing is also sealed by an end cap. A signal photodiode is placed behind a sealed window to receive the collimated beam from the Transmitter.

The primary difference between the ALPHA tracka and ALPHA tracka II is that the Alphatracka II is implemented with surface-mount technology; this has enabled a much smaller diameter pressure housing to be used while retaining exactly the same optical train as in the Mark I. Data from the Mark II version are thus fully compatible with that already obtained with the Mark I. The performance of the Mark II is further enhanced by two electronic developments from Chelsea Technologies Group - firstly, all items are locked in a signal nulling loop of near infinite gain and, secondly, the signal output linearity is inherently defined by digital circuitry only.

Among other advantages noted above, these features ensure that the optical intensity of the Mark II, indicated by the output voltage, is accurately represented by a straight line interpolation between a reading near full-scale under known conditions and a zero reading when blanked off.

For optimum measurements in a wide range of environmental conditions, the Mark I and Mark II are available in 5 cm, 10 cm and 25 cm path length versions. Output is default factory set to 2.5 volts but can be adjusted to 5 volts on request.

Further details about the Mark II instrument are available from the Chelsea Technologies Group ALPHA tracka II specification sheet .

Chelsea Technologies Photosynthetically Active Radiation (PAR) Irradiance Sensor

This sensor was originally designed to assist the study of marine photosynthesis. With the use of logarithmic amplication, the sensor covers a range of 6 orders of magnitude, which avoids setting up the sensor range for the expected signal level for different ambient conditions.

The sensor consists of a hollow PTFE 2-pi collector supported by a clear acetal dome diverting light to a filter and photodiode from which a cosine response is obtained. The sensor can be used in moorings, profiling or deployed in towed vehicles and can measure both upwelling and downwelling light.

Specifications

Operation depth 1000 m
Range 2000 to 0.002 µE m -2 s -1
Angular Detection Range ± 130° from normal incidence
Relative Spectral Sensitivity

flat to ± 3% from 450 to 700 nm

down 8% of 400 nm and 36% at 350 nm

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

Paroscientific Absolute Pressure Transducers Series 3000 and 4000

Paroscientific Series 3000 and 4000 pressure transducers use a Digiquartz pressure sensor to provide high accuracy and precision data. The sensor comprises a quartz crystal resonator that responds to pressure-induced stress, and temperature is measured for thermal compensation of the calculated pressure.

The 3000 series of transducers includes one model, the 31K-101, whereas the 4000 series includes several models, listed in the table below. All transducers exhibit repeatability of better than ±0.01% full pressure scale, hysteresis of better than ±0.02% full scale and acceleration sensitivity of ±0.008% full scale /g (three axis average). Pressure resolution is better than 0.0001% and accuracy is typically 0.01% over a broad range of temperatures.

Differences between the models lie in their pressure and operating temperature ranges, as detailed below:

Model Max. pressure (psia) Max. pressure (MPa) Temperature range (°C)
31K-101 1000 6.9 -54 to 107
42K-101 2000 13.8 0 to 125
43K-101 3000 20.7 0 to 125
46K-101 6000 41.4 0 to 125
410K-101 10000 68.9 0 to 125
415K-101 15000 103 0 to 50
420K-101 20000 138 0 to 50
430K-101 30000 207 0 to 50
440K-101 40000 276 0 to 50

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

James Cook Cruise JC053 AMT20 CTD Processing

Sampling strategy

A total of 89 successful CTD casts were made during the cruise.

All 89 casts were conventional profiling casts with water sampling. Both a stainless steel (SS) and a titanium (TT) CTD system were used. The SS frame was normally deployed daily at ~05:30 and ~13:00 (ship time). The TT frame was normally deployed daily at ~04:30 (ship time); however from 9 th November only the SS frame was used with deployments at ~04:30 and ~13:00 ship time each day. A total of 22 titanium and 67 stainless steel profiles were completed.

Due to a termination failure at 500m on both casts 59 and 60, no bottles could be fired and no data was acquired from the up casts.

Cruise data processing

CTD casts were recorded using the SeaBird data collection software Seasave-Win32. Data were reprocessed at BODC because of concerns about LoopEdit under certain conditions using SBE Data Processing-Win32 v7.20g and the oxygen hysteresis module was used in the calculation of the oxygen channel; the processing routines are named after each stage in brackets. The software applied the calibrations as appropriate through the instrument configuration file to the data in engineering units output by the CTD hardware. The Altimeter data streams were not transferred during processing.

An ascii file including the 24 Hz data for up and down casts was generated along with a bottle file containing all the information from the instant the bottle was fired for each cast (DatCnv). Pressure spikes were removed (WildEdit), the oxygen sensor was then shifted relative to the pressure by 2 seconds, to compensate for the lag in the sensor response time (AlignCTD) and the effect of thermal 'inertia' on the conductivity cells was removed (CellTM). The CTD files produced from SeaBird processing were converted from 24 Hz ascii files into a 2 Hz file (BinAverage). A file was created for each cast containing the mean values of all the variables at the bottle firing locations (Bottle Summary).

During the cruise water samples were collected from rosette bottle on each cast and bench salinometer, Winkler titration and fluorometric analyses made to determine accurate salinity, dissolved oxygen concentration and extracted chlorophyll-a measurements. These data were compared with values from the CTD sensors at bottle firing and a sample calibration derived for the salinity, oxygen and fluorometer channels.

The BBRTD channels have been dropped in the banked files as there are no data for these instruments in the dataset, but these channels are available on request. The calibrated BBRTD profiles will be available separately once they are provided by the scientist responsible for the instrument but the post-cruise calibration has yet to be fully derived and applied.

BODC post-processing and screening

Field Calibrations


Project Information

Oceans 2025 Theme 10, Sustained Observation Activity 1: The Atlantic Meridional Transect (AMT)

The Atlantic Meridional Transect has been operational since 1995 and through the Oceans 2025 programme secures funding for a further five cruises during the period 2007-2012. The AMT programme began in 1995 utilising the passage of the RRS James Clark Ross between the UK and the Falkland Islands southwards in September and northwards in April each year. Prior to Oceans 2025 the AMT programme has completed 18 cruises following this transect in the Atlantic Ocean. This sustained observing system aims to provide basin-scale understanding of the distribution of planktonic communities, their nutrient turnover and biogenic export in the context of hydrographic and biogeochemical provinces of the North and South Atlantic Oceans.

The Atlantic Meridional Transect Programme is an open ocean in situ observing system that will:

The specific objectives are:

The measurements taken and experiments carried out on the AMT cruises will be closely linked to Themes 2 and 5. The planned cruise track also allows for the AMT data to be used in providing spatial context to the Sustained Observation Activities at the Porcupine Abyssal Plain Ocean Observatory (SO2) and the Western Channel Observatory (SO10).

More detailed information on this Work Package is available at pages 6 - 9 of the official Oceans 2025 Theme 10 document: Oceans 2025 Theme 10

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


Data Activity or Cruise Information

Cruise

Cruise Name JC053 (AMT20)
Departure Date 2010-10-12
Arrival Date 2010-11-25
Principal Scientist(s)Andrew Rees (Plymouth Marine Laboratory)
Ship RRS James Cook

Complete Cruise Metadata Report is available here


Fixed Station Information


No Fixed Station Information held for the Series


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