Research links El Niño to Atlantic weather a year later, which could improve long-term weather forecasts

New research has revealed that the impact of one of the world’s most influential global climate patterns is much deeper than initially thought.

Scientists at the UK Meteorological Office have discovered that outside the tropics, the El Niño Southern Oscillation (ENSO) has a further impact on Atlantic weather patterns a full year after the initial event. Research shows that this year-lagged extratropical response to ENSO is as strong as the simultaneous response, but with an opposite impact.

The article is published in the journal Science.

For example, it has been shown that El Niño, which can increase the risk of colder winters in the UK, can lead to a milder winter period the following year.

Although ENSO is just one of many factors that influence the weather in the UK, it can be significant, particularly during the winter months.

Lead researcher Professor Adam Scaife, from the Met Office and University of Exeter, said: “This latest research reveals that El Niño is often followed by a positive North Atlantic Oscillation (NAO) a year later. late, while La Niña is followed by a negative NAO. a year later. The results of this research have major implications for understanding ENSO, explaining the variability of our winter climate, and interpreting long-term forecasts.

Research shows that knowledge of the previous ENSO winter event is also important for understanding some of the UK’s extreme winters. In cases where El Niño is followed by La Niña, or vice versa, lagged effects can amplify expected impacts.

For example, La Niña was followed by El Niño in 1968/69, 1976/77, 2009/10, reinforcing the resulting cold weather, while the UK experienced mild and stormy weather over the winters 1988/89, 1998/99 and 2007. /8 when El Niño was followed by La Niña.

ENSO moves irregularly every two to seven years, causing predictable changes in ocean surface temperatures and disrupting wind and precipitation patterns in the tropics.

With a better understanding of the teleconnections and impacts of ENSO, meteorologists will be better able to reproduce them in climate models and better plan for variations in winter weather conditions.