Flood threat from 'rivers' of air
Published 24/07/2013 | 00:13
Water-laden "rivers" of flowing air are likely to bring more flooding misery to the UK as a result of climate change, scientists predict.
Atmospheric rivers (ARs) are narrow saturated air currents that cause heavy, long-lasting winter rain in mid-latitude regions of the Earth.
They can carry enormous amounts of water. In 2009, an AR responsible for flooding in the north west of Britain transported 4,500 times more water than the River Thames.
A new study has shown that ARs affecting the UK are expected to become stronger and more frequent by the end of the century because of global warming.
Scientists used five climate models to simulate conditions between 2074 and 2099 based on forecasts of greenhouse gas emissions.
All the models indicated a doubling of AR frequency compared with that seen during the period 1980 to 2005.
An increase in the intensity of ARs, leading to greater amounts of rain, was also predicted.
David Lavers, from the University of Reading, who led the study published in the journal Environmental Research Letters, said: "ARs could become stronger in terms of their moisture transport. In a warming world, atmospheric water vapour content is expected to rise due to an increase in saturation water vapour pressure with air temperature. This is likely to result in increased water vapour transport.
"The link between ARs and flooding is already well established, so an increase in AR frequency is likely to lead to an increased number of heavy winter rainfall events and floods. More intense ARs are likely to lead to higher rainfall totals, and thus larger flood events."