Winds Hide Atlantic Variability from Europe’s Winters

2016-06-28T19:24:22+00:00 March 18, 2016|
The map reflects how the winds blowing towards Europe shift with fluctuations in North Atlantic sea-surface temperature. During decades when the sea is cool (associated with blue colors), the prevailing winds are more likely to flow across the Atlantic from North America, keeping western European air temperatures mild. In periods when the ocean surface warms (associated with red), the prevailing winds are more prone to sweep down from the north. (Credit: Ayako Yamamoto)

(Click to enlarge) The map reflects how the winds blowing towards Europe shift with fluctuations in North Atlantic sea-surface temperature. During decades when the sea is cool (associated with blue colors), the prevailing winds are more likely to flow across the Atlantic from North America, keeping western European air temperatures mild. In periods when the ocean surface warms (associated with red), the prevailing winds are more prone to sweep down from the north. (Credit: Ayako Yamamoto)

Shifting winds may explain why long-term fluctuations in North Atlantic sea surface temperatures have no apparent influence on Europe’s wintertime temperatures.

(From ScienceDaily) — The findings, published in Nature Communications, could also have implications for how Europe’s climate will evolve amid global warming.

In the mid-1990s, scientists assembled the first century-long record of North Atlantic sea surface temperatures and quickly discovered a cycle of heating and cooling at the surface of the ocean. Each of these phases lasted for decades, even as temperatures warmed overall during the course of the century. Since this discovery, these fluctuations in ocean temperature have been linked to all manner of Northern Hemisphere climate disturbances, from Sahel drought to North Atlantic hurricanes.

Research also linked European climate variability to the temperature swings of its neighboring ocean in the spring, summer and fall. Surprisingly, however, no imprint of the ocean’s variability could be found in Western Europe’s wintertime temperature record. This absence was especially puzzling in light of the fact that Europe’s mild winters are a direct consequence of its enviable location downwind of the North Atlantic.

Now, a study by researchers at McGill University and the University of Rhode Island suggests that the answer to this puzzle lies in the winds themselves. The fluctuations in ocean temperature are accompanied by shifts in the winds. These wind shifts mean that air arrives in Western Europe via very different pathways in decades when the surface of the North Atlantic is warm, compared to decades when it is cool.

Read the full article here: https://www.sciencedaily.com/releases/2016/03/160315085931.htm