Middle-sized Ocean Eddies Impact Weather

(ETH Zurich, July 08, 2013)

Ocean currents have a big impact on weather and climate. Without the Gulf Stream, for example, the climate of Northern and Western Europe would be cooler. Scientists at ETH Zurich uncovered that also relatively small swirling motions in the ocean, so called eddies, impact weather. A large number of such eddies exists in all oceans at any time, featuring diameters of about one hundred kilometers. The scientists analysed comprehensive satellite data collected over nearly a decade, containing information for more than 600'000 transient eddies. It turned out that depending on the temperature, eddies can locally lead to either more or less wind, clouds and rain. Although the effect is small, the effect of the eddies increases the variability of the atmosphere and hence may influence extreme weather events locally.