Science Week 2016: The Irish Buoy Network
18 November 2016
The Irish Buoy Network was established in 2000 and we now have five buoys operating around the coast of Ireland. The project today is the result of a successful collaboration between Met Éireann, the Marine Institute, the UK Met Office and the Department of Transport, Tourism and Sport.
(left) Met Éireann marine weather services sea area map (right) an ODAS type buoy
The first buoy was deployed at the M1 site west of the Aran Islands, on 6th November 2000 and operated until 2007. The second buoy, M2, was deployed the following May and further buoys were added annually up to 2006 when the M6 was introduced. At that stage there were six buoys operating and the M1 was withdrawn until extra funding could be found to keep the network at six buoys. The M4 buoy was originally deployed in Donegal Bay but was moved to its present position in May 2007 to give a more representative picture of the wave climate in the North West.
Originally an ODAS buoy was used in the network but between 2011 and 2013 a Fugro buoy was introduced. Currently M2, M3, M4 & M5 are Fugro buoys capable of measuring individual waves and distinguishing between wind waves and swell. These buoys also use sonic anemometers which are more suited to maritime conditions compared to the cup anemometers on the ODAS buoys. The moving parts on the cup anemometer can be contaminated over a period of time with sea salt. The Fugro buoys also use Iridium satellites to transmit their messages compared to the ODAS buoys which used Inmarsat.
A new generation of buoys is planned after 2017 when a Mobilis buoy will be introduced into the network by the Marine Institute. This buoy is very robust and can withstand a harsh marine environment similar to the one in the north east Atlantic. This buoy type presents easy access to its underwater instrumentation from within its tower. The meteorological sensors and antennae are mounted within a strong protection ring whilst still allowing exposure to the elements that they are installed to measure. The buoy's wide diameter makes it very stable while operating and allows for easier servicing of the station. The large solar power array and battery bank are significant advantages this buoy has over the Fugro buoy.
The buoys record significant wave height and the record for this parameter is held by the M6 buoy, which measured a 17.2 m significant wave height on 9th December 2007. Individual waves can be over twice the size of significant wave height so in theory we could expect individual waves of over 30 m. The Kinsale Gas Rig measured a 25 m individual wave in 2014 and since the introduction of the Fugro buoy an individual wave of 23.4 m was recorded by Buoy M4 during a very stormy winter. The M4 buoy also recorded the highest wind speed and gust of 57 kts and 76 kts on 8th January 2008.
The network has greatly enhanced our forecasting ability and the buoy reports are an integral part of our Sea Area Forecast. It is impossible to quantify the savings, both in loss of life and property that the network is directly responsible for, but the cost of running the network is a very small percentage of this. So when the next one hundred foot wave is generated off our coast, we hope our buoy network will be there to record the day.
Monthly records for the buoy network can be viewed at http://www.met.ie/marine/marine_map.asp
For further information contact Columba Creamer (Columba dot Creamer AT met dot ie).