Scientists Baffled by Strange Disruption of Wind Pattern in Earth's Stratosphere

09/06/2016 18:21

Quasi-biennial oscillation

Scientists at the National Aeronautics and Space Administration (NASA) are baffled by the recent disruption of the repeating wind pattern in the stratosphere.

According to a paper published in the journal Geophysical Research Letters, the disruption of the usual wind pattern in the stratosphere could have a wide influence in the stratospheric conditions. It is already known that the peak of the two phases of the wind pattern in the stratosphere could change the ozone at the equator by 10 percent, making it more likely that the recent disruption in the wind pattern to have potential implications to the ozone levels.

In 1953, weather balloons were released in the tropics at various points around the globe to measure the wind in the stratosphere, which is about 10 to 30 miles above the Earth's surface. In the 1960s, scientists observed that the wind in the stratosphere circulate the planet in alternating westerly and easterly directions. When westerly winds developed at the tops of the stratosphere starts its gradual descent to the bottom, a layer of easterly winds replaced them at the top. On the other hand, westerly winds replace easterly winds in the top when it begins to descend.

This wind pattern was named "quasi-biennial oscillation" and takes about 28 months to repeat. Since its initial observation, the quasi-biennial oscillation remains unchanged. However, scientists noticed that in the end of 2015 the descending westerly winds appeared to move upwards and blocked the downward movement of easterly winds. This disruption of the pattern held for nearly half a year, with the usual pattern returning back in July 2016.

"The quasi-biennial oscillation is the stratosphere's Old Faithful," said Paul Newman, Chief Scientist for Earth Sciences at NASA's Goddard Space Flight Center, Greenbelt, Maryland, and lead author of the study, in a press release. "If Old Faithful stopped for a day, you'd begin to wonder about what was happening under the ground."

NASA scientists are now looking into possible causes of the recent shift in the quasi-biennial oscillation. They are trying to determine whether the particularly strong El Niño in 2015 or the long-term trend of rising global temperatures is the cause of the disruption.

Furthermore, the scientists also want to know if the disruption is a naturally-occurring phenomenon or an unwanted effect of the climate change. NWN

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