The upper reaches of the atmosphere influence oceanic circulation, reports a study published online in Nature Geoscience this week. The finding suggests that the upper atmosphere - often ignored in climate models - can affect climate over decadal timescales.
Thomas Reichler and colleagues examined the influence of winds in the stratosphere - that layer of the atmosphere stretching between 10-50 km altitude - on circulation in the North Atlantic Ocean, using meteorological and ocean data collected over the past 30 years. They show that stratospheric and Atlantic Ocean circulations co-varied over this time. Climate model simulations suggest that stratospheric circulation patterns, such as those observed, perturb the surface of the Atlantic Ocean, triggering changes in ocean circulation patterns over timescales of decades. As such, the findings show that signals from the stratosphere can penetrate the entire atmosphere-ocean system, and should not be ignored in climate change studies.