Weather supercomputer will give forecasters more accuracy

Met Éireann has announced the completion of a massive reprocessing of Irish weather data going back decades, which has enabled a detailed reconstruction of recent weather patterns in Ireland.

The data produced with the help of a supercomputer will enable much more accurate interpretation of the Irish climate, including extreme weather events and flooding. It will also allow for better understanding of climate change in Ireland, and help interpret weather as it unfolds in a large area across Ireland, Britain and part of France.

Details of the newly reanalysed climate dataset, produced under the MÉRA (Met Éireann ReAnalysis) project, were outlined on Friday by Met Éireann director Eoin Moran at Dublin City University’s Alpha innovation campus. He described the data as a new “cornerstone for studies of Irish climate”.

Researchers and representatives of sectors affected by weather were provided with a day-long briefing. Among those who will benefit from the research are the Office of Public Works, which has responsibility for flood prevention in Ireland; the Marine Institute, the farming sector, renewable energy interests, climate adaptation/mitigation services, insurance companies and scientists involved in atmospheric research, according to Met Éireann.

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“Any study of climate change must be grounded in a foundation of solid knowledge about our past and recent climate. Climate reanalysis is a scientific method for reconstructing the recent climate of Ireland in three dimensions through the use of advanced computer-based techniques to recreate past weather,” said Dr Saji Varghese, head of research at Met Éireann’s environment and applications division.

Observations

Climate scientists used detailed mathematical models of the atmosphere and primed them with all observations (weather data that comes from Met Éireann weather stations around the county) to develop a complete reanalysis of Irish weather patterns stretching back over decades. Such a record of how weather and climate have changed over time provides additional and much more detailed information to that from the weather observation networks, according to Dr Emily Gleeson, senior scientist in Met Éireann.

This reanalysis produces a rich dataset that describes, in great detail, the behaviour of the Irish weather “over the last 30 years and more”. It will itself provide the “raw material” for climate scientists to further study and elucidate the changes that are underway in our climate, she said.

Climate reanalyses are an important source of information for monitoring and analysing past climate in the context of climate change. This new dataset, and studies that flow from it, would help society, and policymakers in particular, to further understand future climate risks and to prepare appropriately adaptation strategies to deal with future weather.

Over the past three years, Met Éireann researchers availed of a state-of-the-art weather prediction system running on some of the most powerful computing resources available to European science. MÉRA created 900 terabytes of data – equivalent to 1.3 million audio CDs – and used 12.5 million computer hours. Through Ireland’s membership of the European Centre for Medium-Range Weather Forecasts, the production of these data was made possible through exploitation of the processing capabilities of its supercomputer in Reading in the UK.

Highest resolution

The dataset has been produced on a spatial resolution of 2.5km for the period from 1981 to 2015 and is the highest resolution reanalysis dataset available today for the Irish-UK region. “MÉRA will greatly extend the knowledge gained from weather observations and will have relevance in many sectors of study related to understanding our atmosphere and our environment,” said Dr Gleeson. The high resolution achieved means you can “see” the landscape better, it can model weather variables better as mountains affect how the air moves, and moving air (along with the sun) are the drivers of weather.

“The availability of this new high quality MÉRA open dataset will enable academic, public and private sector users of weather and climate data to develop and provide value-added, sector-specific local information about how future weather is likely to affect every man, woman and child living on this island,” Met Éireann said.