Metadata Report for BODC Series Reference Number 895313

• 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

BODC Processing

BODC Processing

The data arrived at BODC in Matlab binary .txt format. The file was over 2 MB in size and was at a resolution of 8Hz. The size of the file presented some problems to processing. Firstly the BODC BUDs system was used to interpret the data into 10 minute intervals. The file then underwent further processing by converting to qxf format following BODC samples schema transfer procedures and using BODC generated Matlab code. BODC parameter codes are used to map the variables measured. Below is a table showing the parameter mapping.

The data were screened using BODC's in-house EDSERPLO visualisation software.

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:

• Irregularities such as unfeasible values
• Inconsistencies between related information, for example:
  • Times for instrument deployment and for start/end of data series
  • Length of record and the number of data cycles/cycle interval
  • Parameters expected and the parameters actually present in the data cycles
• Originator's comments on meter/mooring performance and data quality

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:

• Spurious data at the start or end of the record.
• Obvious spikes occurring in periods free from meteorological disturbance.
• A sequence of constant values in consecutive data cycles.

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:

• Maximum and minimum values of parameters (spikes excluded).
• The occurrence of meteorological events.

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.

Originator's Processing

The AML CT Logger measures conductivity and temperature from its three sensor heads. Bench testing at POL showed that the system was working in autonomous mode using SyncGen1 to supply timing triggers. The CT Logger was also set-up to accept power from a POL designed external alkaline battery pack instead of its normal internal and external lithium cell battery packs. The internal lithium battery pack was removed for saftey and recycling as were the cells in the external battery pack. The existing short aluminium cased external battery pack used for the old STD12plus CT logger, was adapted to power the CT Logger system.

The CT Logger was set to sample at 8 Hz due to a minimum response time for the temperature sensors of 0.1 seconds.

Project Information

Proudman Oceanographic Laboratory Dee Experiment

Introduction

Sediment transport process models are a vital tool in allowing scientists to predict sediment transport and forecast seabed and coastal morphodynamic evolution. It is however, difficult to obtain accurate models due to the complex inter-dependence of sediment processes in the bottom boundary layer. This inter-dependence is governed by interactions between the sediment transport triad; the bed, the hydrodynamics and the mobile sediments.

Scientific Objectives

• To use a varying suite of instruments to make co-located measurements of the sediment triad
• To provide a framework to allow assessment and improvement of the latest sediment transport models
• To address dynamics of suspended sediments in terms of supply of material to the coastal zone from estuaries
• Development of a new description of suspended sediment and water opacity to improve simulation of coastal primary productivity

Fieldwork

The study site chosen by POL for this research was the Dee Estuary, Liverpool Bay. POL performed fieldwork in the Hilbre Channel on the eastern side of the Estuary and the Welsh Channel on the western exit of the Estuary, with emphasis placed on two repeat stations, HC and WC. The fieldwork started in February 2005 and has been summarised below:

Funding

The Dee Experiment project was core funded by POL under Programme 2 (Shallow coastal seas) Theme 5 (Coastal and sediment processes) of POL's Science Programme 2001 - 2006. From March 2007 onwards, this core funding was replaced by funding from NERC's Oceans 2025 programme and the Dee Experiment research continued as part of Oceans 2025 Work Package 3.3.

Data Activity or Cruise Information

Data Activity

Dee Estuary Experiment Stable3

Deployment Information

Recovery Information

The following table gives the position of frame Stable3.

The frame's instrumentation is detailed in the below table:

The ADVs were mounted at separate heights on a vertical pole with the transmitter axis pointing horizontally, i.e. perpendicular to the sea surface/sea bed.

The frame was of a tripod design with the following overall dimensions (all measurements +/- 0.005 m):

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: