Metadata Report for BODC Series Reference Number 2079686

• 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

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

Metrohm 716 DMS Titrino titrator

The Metrohm 716 DMS Titrino is a titrator used for five basic methods of titrations. These include DET (Dynamic Equivalence-point Titration), MET (Monotonic Equivalence-point Titration), SET (end-point titration), MEAS (measuring instrument for pH, voltage and temperature) and CAL (pH calibrations) titrations.

The instrument consists of an exchange unit, magnetic swing out stirrer, display, indicator lamps, control keys and a separate keypad. Exchange units are available in brown or clear glass with light protection. The models with light protection or brown glass should be used for light sensitive reagents. The Metrohm 716 has a built-in RS232C interface for communication with a PC and printers. Optional accessories for the Metrohm 716 include Ti stands for rinsing and addition of fresh solvent, balances, analog recorders and sample changers.

Specifications

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

Niskin Bottle

The Niskin bottle is a device used by oceanographers to collect subsurface seawater samples. It is a plastic bottle with caps and rubber seals at each end and is deployed with the caps held open, allowing free-flushing of the bottle as it moves through the water column.

Standard Niskin

The standard version of the bottle includes a plastic-coated metal spring or elastic cord running through the interior of the bottle that joins the two caps, and the caps are held open against the spring by plastic lanyards. When the bottle reaches the desired depth the lanyards are released by a pressure-actuated switch, command signal or messenger weight and the caps are forced shut and sealed, trapping the seawater sample.

Lever Action Niskin

The Lever Action Niskin Bottle differs from the standard version, in that the caps are held open during deployment by externally mounted stainless steel springs rather than an internal spring or cord. Lever Action Niskins are recommended for applications where a completely clear sample chamber is critical or for use in deep cold water.

Clean Sampling

A modified version of the standard Niskin bottle has been developed for clean sampling. This is teflon-coated and uses a latex cord to close the caps rather than a metal spring. The clean version of the Levered Action Niskin bottle is also teflon-coated and uses epoxy covered springs in place of the stainless steel springs. These bottles are specifically designed to minimise metal contamination when sampling trace metals.

Deployment

Bottles may be deployed singly clamped to a wire or in groups of up to 48 on a rosette. Standard bottles and Lever Action bottles have a capacity between 1.7 and 30 L. Reversing thermometers may be attached to a spring-loaded disk that rotates through 180° on bottle closure.

D381A and D381B Discrete CTD Oxygen Sampling Document

The following contains extracts from the D381A/B cruise report.

Originator's Protocol For Data Acquisition And Analysis

Water samples were collected from 21 CTD casts during cruise D381. The samples were obtained using an SBE 911plus CTD unit with 24 Niskin bottles (10 litre) fitted to the rosette. All seawater samples were drawn through silicone tubing from the Niskin bottles into clear, pre-calibrated borosilicate glass bottles. The temperature of the samples was measured using a hand-held digital thermometer. 1 mL of manganous chloride and 1 mL alkaline iodide was added to the sample bottles before inserting a glass stopper to be bottles and shaking vigorously for 30 seconds. The samples were then left for 1 hour before being shaken again and then left for a further hour.

The method used for analysis was the Winkler whole bottle titration method with spectrophotometric end point. 1 mL of dilute sulphuric acid was added to the sample bottles (280 mL of H2SO4 per 1 litre of milli-Q water) before inserting a small magnetic stirrer bar to each sample bottle whilst standing the bottles on a magnetic stirring plate to facilitate dissolution. Each bottle was titrated with sodium thiosulphate until it was clear. The volume of the titration was recorded for use in the oxygen concentration calculation.

Cast 15 and 21 were submitted to BODC without a cast end time. Therefore this has been taken as the time the last bottles were fired.

BODC Data Processing Procedures

Discrete oxygen concentration data were supplied to BODC in a single .mat file. The values were extracted and loaded into BODC's ORACLE database. No data were considered improbable, therefore no flags were added.

Parameter details of the data are displayed in the table below:

Data Quality Issues

In some instances the CTD casts had bottles fired whilst the CTD was moving upwards through the water column, this was done to reduce overall deployment time. For specific information, please see the cruise report.

Two CTD packages were deployed during cruise D381 as the entire CTD package was lost on cast 13 when the wire parted.

For each Niskin bottle, two oxygen samples were submitted. BODC averaged duplicate values and from the duplicate values calculated the standard deviation.

References Cited

Naveira-Garabato A.C. et al.(2012). 'Ocean Surface Mixing, Ocean Sub-mesoscale Interaction Study'. Cruise Report National Oceanography Centre, Southampton.

Project Information

Ocean Surface Mixing, Ocean Sub-mesoscale Interaction Study (OSMOSIS)

Background

The Ocean Surface Mixing, Ocean Sub-mesoscale Interaction Study (OSMOSIS) consortium was funded to deliver NERC's Ocean Surface Boundary Layer (OSBL) programme. Commencing in 2011, this multiple year study will combine traditional observational techniques, such as moorings and CTDs, with the latest autonomous sampling technologies (including ocean gliders), capable of delivering near real-time scientific measurements through the water column.

The OSMOSIS consortium aims to improve understanding of the OSBL, the interface between the atmosphere and the deeper ocean. This layer of the water column is thought to play a pivotal role in global climate and the productivity of our oceans.

OSMOSIS involves collaborations between scientists at various universities (Reading, Oxford, Bangor, Southampton and East Anglia) together with researchers at the National Oceanography Centre (NOC), Scottish Association for Marine Science (SAMS) and Plymouth Marine Laboratory (PML). In addition, there are a number of project partners linked to the consortium.

Scientific Objectives

• The primary goal of the fieldwork component of OSMOSIS is to obtain a year-long time series of the properties of the OSBL and its controlling 3D physical processes. This is achieved with an array of moorings (two nested clusters of 4 moorings, each centred around a central mooring) and gliders deployed near the Porcupine Abyssal Plain (PAP) observatory. Data obtained from this campaign will help with the understanding of these processes and subsequent development of associated parameterisations.
• OSMOSIS will attempt to create parameterisations for the processes which determine the evolving stratification and potential vorticity budgets of the OSBL.
• The overall legacy of OSMOSIS will be to develop new (physically based and observationally supported) parameterisations of processes that deepen and shoal the OSBL, and to implement and evaluate these parameterisations in a state-of-the-art global coupled climate model, facilitating improved weather and climate predictions.

Fieldwork

Three cruises are directly associated with the OSMOSIS consortium. Preliminary exploratory work in the Clyde Sea (September 2011) to hone techniques and strategies, followed by a mooring deployment and recovery cruise in the vicinity of the Porcupine Abyssal Plain (PAP) observatory (in late Summer 2012 and 2013 respectively). Additional opportunist ship time being factored in to support the ambitious glider operations associated with OSMOSIS.

Instrumentation

Types of instrumentation and measurements associated with the OSMOSIS observational campaign:

• Ocean gliders
• Wave rider buoys
• Towed SeaSoar surveys
• Microshear measurements
• Moored current meters, conductivity-temperature sensors and ADCPs
• Traditional shipboard measurements (including CTD, underway, discrete nutrients, LADCP, ADCP).

Contacts

Data Activity or Cruise Information

Data Activity

BODC Sample Metadata Report for D381B_CTD_C019

Please note:the supplied parameters may not have been sampled from all the bottle firings described in the table above. Cross-match the Sample Reference Number above against the SAMPRFNM value in the data file to identify the relevant metadata.

Cruise

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:

SeaDataNet Quality Control Flags

The following single character qualifying flags may be associated with one or more individual parameters with a data cycle: