title: 'Arctic ice key to jet stream pattern changes' published: true publish_date: '31-08-2016 14:56' taxonomy: category:
- Politics tag:
- Climate change
- Arctic sea 'Post Type':
Reductions in Arctic sea ice levels have a greater effect on patterns of atmospheric circulation beyond the Arctic than previously thought. New research in the International Journal of Climatology indicates implications far beyond the Arctic leading to a weaker jet stream and less storminess in the mid-latitudes. The jet stream consists of ribbons of very strong winds which move weather systems around the globe. Jet streams are found 9-16 km above the surface of the Earth. The new data Scientists ran two 30-year simulations, one using climate data on the Arctic sea ice for the end of the 20th century and the other using observed sea ice extent from 2007. The experiments showed that the atmospheric response to increased open water in the Arctic was signi?cant. The report said: "This atmospheric response could have implications beyond the Arctic such as a decrease in the pole to equator temperature gradient (given the increased temperatures associated with the increase in open water, leading to a weaker jet stream and less storminess in the mid-latitudes." Global travel The jet stream has a significant effect on northern European weather, as well as global air travel, in that it affects headwind and tailwind, and thus journey time. Circulation differences over the northern hemisphere were most prominent during autumn and winter with lower sea level pressure (SLP) and tropospheric pressure simulated over much of the Arctic for the 2007 sea ice experiment. In summer, large differences were shown between the observed and simulated sea level pressure. SLP also suggested that the sea ice conditions in the months preceding and during the summer of 2007 were not responsible for creating an atmospheric circulation pattern which favoured the large observed sea ice loss. The simulated and observed atmospheric circulation differences during autumn and winter suggest that the forced atmospheric response to reduced sea ice was in part responsible for atmospheric circulation anomalies during autumn and winter.