Image of jet stream over the North Atlantic and UK, courtesy of Crondallweather.co.uk
Maynooth University ICARUS Climate Research Centre compares the jet stream over North Atlantic, Eurasia, America and North Pacific
New research at Maynooth University’s ICARUS Climate Research Centre has found that the jet stream is moving northwards, influencing storm activity and temperature patterns across the Northern Hemisphere. The average winter northern hemisphere jet stream position over the North Atlantic and Eurasia has moved northwards by up to 330km, and the mean winter jet speed has increased by 8% to 132mph, during the 141-year period from 1871-2011
Jet streams are fast bands of air which flow around the globe at around ten thousand metres above the Earth’s surface and have a significant influence on storm activity and temperature patterns across the northern hemisphere which can impact the weather through strong winds and flooding events. This is the longest regional study of the northern hemisphere jet stream and the research finds that the trends observed are potential indicators of climate change.
According to the study published this week in the peer-reviewed scientific journal, Climate Dynamics, provides a regional (land – ocean) comparison of the Northern Hemisphere jet stream, and finds that jet stream trends vary on a regional and seasonal basis. Between 1871 and 2011 the average winter jet stream latitude over the North Atlantic moved from 44° to 47° north with a 10 mph increase in speed to 132mph, but no increases were observed over the North Pacific.
The lead author of the paper, Dr Samantha Hallam, of the ICARUS Climate Research Centre at Maynooth University in Ireland, said:
“Significant increases in winter jet latitude and speed are observed over the North Atlantic and Eurasia which is consistent with the decreasing temperature and increasing pressure gradients observed respectively between the equator and the Arctic over the period.”
“Over the North Pacific, no increase in jet latitude or speed are observed, however, changes in the North Pacific sea surface temperatures explains over 50% of the variability in jet latitude “
“The results highlight that Northern Hemisphere jet variability, and trends differ on a regional basis. This is important for making climate predictions and in developing plans to combat climate change,” she added.
These findings are the result of a statistical analysis of the 250mb jet stream using the Twentieth Century Reanalysis dataset. The research was supported by the Marine Institute and funded by the Irish Government under the JPI Climate and JPI Ocean joint call project ROADMAP and the Natural Environmental Research Council, and involved collaboration ICARUS Climate Research Centre at Maynooth University in Ireland, University of Southampton, UK, and National Oceanography Centre, UK.
Read the full article : A regional (land–ocean) comparison of the seasonal to decadal variability of the Northern Hemisphere jet stream 1871–2011
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