Unknown deviation alters 60-year-old wind pattern in Stratosphere

New Delhi: Scientists have been observing the steady circulating wind pattern of the Earth's stratosphere that repeats itself every two years for the past six decades.

The wind circulation, dubbed as quasi-bennial oscillation, is a wind pattern in stratosphere that extends from about 10 to 30 miles above Earth’s surface. It circulate the planet in alternating easterly and westerly directions over roughly a two-year period.

Westerly winds develop at the top of the stratosphere, and gradually descend to the bottom, about 10 miles above the surface while at the same time being replaced by a layer of easterly winds above them. In turn, the easterlies descend and are replaced by westerlies.

This wind circulation has never change, until 2015. As the year approaches end, the winds from west start switching their pattern and rose right back upward blocking the downward movement of the eastern winds. This new pattern held for nearly half a year, and by July 2016 the old regime seemed to resume.

Scientists at NASA's Goddard revealed this change in stratospheric wind pattern in a paper in Geophysical Research Letters. “The quasi-biennial oscillation is the stratosphere’s Old Faithful,” Paul Newman, lead scientist on the paper from NASA Goddard said in a statement. “If Old Faithful stopped for a day, you’d begin to wonder about what was happening under the ground.”

He suggested two potential hypotheses that could explain this sudden alteration in the wind pattern- the particularly strong El Niño in 2015-16 or the long-term trend of rising global temperatures, according to NASA.