Galway Bay Cable Observatory Data Files

Last updated 30th November 2015 | Adam Leadbetter

Table of Contents

  1. General Directory Structure
  2. Instruments
    1. Conductivity Temperature Depth sensor
    2. Fluorometer
    3. Acoustic Doppler Current Profiler
    4. Hydrophone
    5. Acoustic Telemetry

General Directory Structure

The data files are arranged in a directory structure by instrument type, specific instrument, and then year, month, day e.g.

- {InstrumentTypeA}
		| - {InstrumentMakeModelSerialNumberA}
			|- 2015
				|- 10
					|- 01
					|- 02
	- {InstrumentTypeB}
		|- {InstrumentMakeModelSerialNumberB}
			|-2015
					|- 10
					|- 01
					|- 02

During the day, data files are streamed from the sensors to these directories. At the end of the day an archive file is created containing the full set of data produced during the day. For line oriented data, a single .txt file containing the concatenated results is created. For file oriented data, both a .zip and a .tar.gz compressed archive of the day's files is created in the folder. Once the daily archive has been produced, the individual files may be removed. After the end of a month, a .zip and a .tar.gz archive for the full month is also created for ease of data delivery.

Instruments

Conductivity Temperature Depth sensor

An Idronaut Ocean-Seven 304 Conductivity-Temperature-Depth probe is installed on the observatory infrastructure. It measures the temperature and conductivity of the seawater (the conductivity is used to calculate an estimate of the salinity); the pressure exert by the seawater above (from which the depth of the sensor is estimated); and these parameters are also used to estimate the speed of sound within the sea.

The data files produced by the CTD are available here. The data files contain the following columns:

Date-time|InstrumentID| {Tab separated data columns}

Fluorometer

A WetLabs ECO-FLNTU (serial number #3137) is installed on the observatory infrastructure. It measures the fluorescence of the seawater to give an estimate of the volume of chlorophyll present (indicative of the amount of phytoplankton in the seawater) and it measures turbidity, or the "cloudiness" of the seawater, caused by the presence of particles such as sediment from the seabed suspended in the water.

The data files produced by the fluorometer are available here. The data files contain the following columns:

Date-time|InstrumentID| {Tab separated data columns}

Acoustic Doppler Current Profiler

A Teledyne RDI Workhorse Broadband 600KHz acoustic Doppler current profiler (ADCP - serial number 1323) is mounted on the observatory infrastructure. It is approximately two metres above the seabed, looking up towards the sea surface. Data are collected every minute for 0.5m depth bins from 1 metre above the instrument to the surface.

Data are collected in RDI's PD0 binary format, and made available to access here. A brief description of PD0 format can be found here and tools are available for Python, R and various other languages to read the PD0 files.

During the current day, files are available for each minute of observation. Each night, these are concatenated to produce a daya file, and a single file is produced at the end of each month for that month's observations.

Hydrophone

An OceanSonics icListen hydrophone is deployed on the observatory infrastructiure to monitor ocean noise in the region of the observatory. The wave form data collected by the hydrophone is processed to a summary file by a Fast Fourier Transform. These summary files are available here. The format of the summary files is described in this file.

Acoustic Telemetry

Ocean Tracking Network logo

This instrument is part of the Ocean Tracking Network and the data it generates is copied to Ocean Tracking Network, Dalhousie University, Halifax, Canada.

In order to receive signals from tagged fish and other sea life, a Vemco VR2C acoustic monitoring receiver is deployed. The receiver records the passing of acoustic tags and the identifier of the tags it records. The data are recorded to text files, with the following two formats. For summary data, the following columns are recorded:

2015-11-30T10:52:02.314Z|VMVR2C450117| {comma separated data columns}

For a detection event, the line output becomes:

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