Lasker Award for Professor Sir Peter Ratcliffe

The normal flow of air high up in the atmosphere over the equator, known as the quasi-biennial oscillation, was seen to break down earlier this year. These stratospheric winds are found high above the tropics, and their direction and strength changes in a regular two to three-year cycle, which provides forecasters with an indication of the weather to expect in northern Europe. Westerly winds are known to increase the chance of warm and wet conditions, while easterlies bring drier and colder weather. Scientists from the National Centre for Atmospheric Science (NCAS) at the University of Oxford and the Met Office were part of an international team that observed the unusual behaviour in February, noticing a reversal of the expected pattern in the winds. This same team then identified the reason why. The quasi-biennial oscillation is a regular feature of the climate system. On average, these equatorial eastward and westward winds alternate every 28 to 29 months, making them very predictable in the long term.