In DepthAtmospheric Science

The atmosphere's pacemaker skips a beat

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Science  09 Sep 2016:
Vol. 353, Issue 6304, pp. 1079-1080
DOI: 10.1126/science.353.6304.1079

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Summary

High in the stratosphere, a pendulum called the quasi-biennial oscillation (QBO) swings back and forth, a pacemaker whose regularity helps scientists with seasonal weather forecasts. Roughly every 28 months, winds around Earth's equator switch from westerlies to easterlies and back again. But for the first time since 1960, when scientists first reported the QBO's existence, that beat has been interrupted: Earlier this year, westerly winds did not yield smoothly to easterlies, as expected. Scientists are now scrambling to understand the cause. The disruption may be due to the strong El Niño this past year, a "blob" of warm waters in the northern Pacific Ocean, or a sudden stratospheric warming event this past year. Or climate change may be making the QBO vulnerable in a more fundamental way. In any case, one of forecasters' reliable tools has become more shaky. They thought that Europeans might have looked ahead to a colder, drier winter this coming year. Instead, it may be warm and wet.

  • * Betsy Mason is a freelance writer in the San Francisco Bay Area in California.