Metadata Report for BODC Series Reference Number 1766575

• 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

OSMOSIS Cruise D381A and D381B moored MicroCAT CTDs: Quality Report - Knockdown

From examination of the periods when the recorded pressure is significantly greater than the nominal depth of the moored instrument, BODC consider that for the following approximate time periods, data quality is significantly affected by knockdown of moorings:

• Beginning of the mooring deployment to September 2012.
• 14 November 2013 to 3 December 2013 (only for NE outer mooring).
• 11 January 2013 to 21 January 2013
• 27 January 2013 to 31 January 2013.
• 8 February 2013 to 20 February 2013.
• 5 March 2013 to 7 March 2013.
• 22 March 2013 to 23 March 2013.
• 19 April 2013 to 25 April 2013.
• 3 May 2013 to 8 May 2013.
• 20 May 2013 to 9 June 2013.
• August 2013 to the end of mooring deployment.

All parameters have been flagged as suspect during these periods. Additional flagging has been applied to all parameter where there are significant and obvious spikes in the pressure channel. The above time periods should be used as a guide, there are slight variations between mooring sites.

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 SBE 37-SM MicroCAT

The SBE 37-SM MicroCAT is a high accuracy conductivity and temperature recorder (pressure optional). Designed for moorings and other long-duration, fixed-site deployments, MicroCATs have non-corroding titanium housings rated for operation to 7000 metres or pressure sensor full scale-range. Communication with the MicroCAT is over an internal, 3-wire, RS-232C link. The MicroCAT's aged and pressure-protected thermistor has a long history of exceptional accuracy and stability (typical drift is less than 0.002° per year). Electrical isolation of the conductivity electronics eliminates any possibility of ground-loop noise.

Specifications

Further information can be found via the following link: SBE 37-SM MicroCAT Datasheet

OSMOSIS Cruise D381A and D381B Moored MicroCAT CTDs: Originator's Data Processing

The originator has supplied short-term MicroCAT CTD data for outer mooring sites (NW, NE, SW, SE), inner mooring sites (NW, NE, SW, SE) and a central mooring site as part of the Ocean Surface Mixing, Ocean Sub mesoscale Interaction Study (OSMOSIS) consortium project.

The short-term moorings were deployed on the RRS Discovery Cruise D381A and D381B in 2012 and were recovered a year later on the RRS James Cook Cruise JC090.

Originator's Data Processing

The originator has applied the following processing steps to each MicroCAT CTD file.

• Converted original .xml binary files to .cnv files
• Read into Matlab and formatted into Matlab structures
• Data sorted by depth and plots created to assess data quality
• Quality control flags were applied to parameters where applicable and the overall file
• Data collected during deployment and recovery activities, as ascertained from the pressure readings, were removed

Data quality issues were observed by the originator, which have been outlined below for future user awareness.

• NE inner mooring, serial no. 9381 - data unavailable.
• Centre mooring, serial no. 9398 - offset observed and possible drift in pressure sensor readings. Pressure readings poor after 2013-07-25 21:33:07. The data has been retained and flagged accordingly.
• Centre mooring, serial no. 9399 - observed poor salinity readings and poor temperature readings as shown by lagged temperature responses during post-experiment recovery.
• NE outer mooring, serial no. 7298 - poor salinity readings, the data have been retained and flagged accordingly.
• NE outer mooring, serial no. 7299 - poor salinity readings, the data have been retained and flagged accordingly.
• NE outer mooring, serial no. 7302 - poor salinity readings, the data have been retained and flagged accordingly.
• NW outer mooring, serial no. 7293 - poor salinity readings, the data have been retained and flagged accordingly.
• NW outer mooring, serial no. 7294 - poor salinity readings, the data have been retained and flagged accordingly.
• NW outer mooring, serial no. 7296 - data unavailable.
• NW outer mooring, serial no. 7297 - poor salinity readings, the data have been retained and flagged accordingly.
• SE inner mooring, serial no. 7315 - bias observed in salinity readings, adjustments made by subtracting off a constant (-0.0068 psu) value.
• SE inner mooring, serial no. 9389 - poor salinity readings, the data have been retained and flagged accordingly.
• SE outer mooring, serial no. 7305 - poor salinity readings, the data have been retained and flagged accordingly.
• SE outer mooring, serial no. 7306 - poor salinity readings, the data have been retained and flagged accordingly.
• SE outer mooring, serial no. 7309 - poor salinity readings, the data have been retained and flagged accordingly.
• SW inner mooring, serial no. 9372 - observed poor pressure readings, therefore data was interpolated from pressure readings from SW inner mooring serial no. 8080 Aquadopp. Exact distances between sensors are unknown, it is recommended for the user to take caution using data.
• SW inner mooring, serial no. 9374 - bias observed in salinity readings, adjustments made by subtracting off a constant (0.0408 psu) value. Pressure readings altered using post-experiment recovery calibration curve.
• SW inner mooring, serial no. 9375 - poor salinity readings, the data have been retained and flagged accordingly.
• SW inner mooring, serial no. 7310 - poor salinity readings, the data have been retained and flagged accordingly.
• SW outer mooring, serial no. 7288 - poor salinity readings, the data have been retained and flagged accordingly.
• SW outer mooring, serial no. 7289 - poor salinity readings, the data have been retained and flagged accordingly.

Field Calibrations

CTD casts were deployed on the mooring deployments to provide reference points for calibration of moored time series measurements. Calibration curves do not exist for the mooring recoveries, as no CTD casts were deployed.

Figure 1. Annual mean temperature and salinity for each MicroCAT sensor; depths correspond to the annual mean depths of each sensor. Salinity sensors are biased (or drift) relative to their true value owing to a lack of a calibration curve at the end of deployment.

OSMOSIS Cruise D381A and D381B moored MicroCAT CTDs: Processing by BODC

Data from 59 MicroCAT sensors were submitted to BODC as Matlab files, one file for each sensor. The table below describes the originators variables and how they were mapped to appropriate BODC parameter codes for standardisation purposes.

The data were visualised in internal built software EDSERPLO. Suspect data were flagged according. Missing data values were set to appropriate values and flagged. All data files were modified by the originator, to remove data points collected during the deployment and recovery of instrumentation.

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

OSMOSIS north-west outer mooring

The short term moorings were deployed and recovered during cruise RRS Discovery D381A as part of the Ocean Surface Mixing, Ocean Submesoscale Interaction Study (OSMOSIS) project.

The target for the north-west outer mooring was 48° 44.940' N, 16° 16.800' W in approximately 4,830 m of water. The mooring consisted of five Nortek Aquadropp single-point current meters and five SBE 37 MicroCAT sensors. In addition, a light and Argo tag were fixed at the top of the mooring.

Instruments deployed on the mooring

Related Data Activity activities are detailed in Appendix 1

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:

Appendix 1: OSMOSIS NW outer

Related series for this Data Activity are presented in the table below. Further information can be found by following the appropriate links.

If you are interested in these series, please be aware we offer a multiple file download service. Should your credentials be insufficient for automatic download, the service also offers a referral to our Enquiries Officer who may be able to negotiate access.