Saturday 21 July 2018

100 years of weather data can give picture of climate change

Alana Phelan enjoys the sunny weather in Galway’s Eyre Square. Picture: Xposure
Alana Phelan enjoys the sunny weather in Galway’s Eyre Square. Picture: Xposure
Paul Melia

Paul Melia

More than 100 years of daily weather records will become available electronically to help produce an accurate picture as to how our climate is changing.

The Central Statistics Office (CSO) and Met Éireann are digitising hand-written paper records dating back to the 1830s and up to 1959 which set out daily rainfall, temperature, air pressure, humidity, wind and other indicators.

The information is already available from 1959, but a complete weather record will help assess how climate change is impacting on our weather systems. Daily data will help shed light on why one particularly wet day resulted in flooding, while a similar level of rainfall on another occasion did not.

Researchers say the secret lies in the days preceding the heavy rain.

"If you have a day of very heavy rain, what you really need to know is what were the ground conditions from a week before," senior statistician at the CSO Gerry Brady said.

"If it was very dry, the land would soak up a lot of the rain so it might not lead to flooding. But if the ground was wet, it could cause flooding. You need the daily data to understand when flooding might or might not happen."

Changes in our weather patterns can impact on the length of the growing season, heighten the risk of flooding and impact on human health due to heat waves or cold spells.

An added bonus of the project is that the age of the records means scientists can research if weather patterns changed after people began taking foreign holidays and as mass car ownership took hold.

"In the 1960s and 1970s, people began to go to Spain and America and drive cars. The period we don't have daily data for is when there wasn't so many cars or aeroplanes, so it (weather) was less influenced by humans," Mr Brady added.

Chief climate scientist at the Environmental Protection Agency, Frank McGovern, said an analysis of rainfall records has already been undertaken by Maynooth University, and the World Meteorological Organisation and UN were both encouraging countries to make historical weather records available for analysis.

Irish Independent

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