For the past 60 years, scientists have been watching how strong winds blow in a continuous circuit around Earth’s tropical stratosphere - a layer up to 48 km (30 miles) above the equator known as quasi-biennial oscillation This has been repeating the same pattern every two years since the 1960s, but late last year, everything changed, it stopped.
http://www.sciencealert.com/a-60-year-old-pattern-in-the-stratosphere-just-went-in-reverse
Great article