El Nino predictions can be improved by learning more about westerly wind bursts

Researchers have revealed that by learning more about the westerly wind bursts would help them predict El Nino events more efficiently.

Study found that prolonged wind bursts originating in the western Pacific can have a strong effect on whether an El Nino event will occur and how severe it is likely to be.

In addition, the paper identified three distinct varieties or "flavors" of El Nino, and explained how these westerly wind bursts (WWBs) could determine which of these flavors will take shape. The findings should help refine future predictions of these global-scale climate events.

The researchers analyzed 50 years of tropical Pacific sea surface temperature and westerly wind burst data. They found differences, especially when comparing the data from this year's weak El Nino event with the record-breaking event of 1997/98.

After adding westerly wind bursts to their intermediate ocean-atmosphere coupled model, the researchers consistently found three "flavors" of El Nino (rather than one, which was the model's output without the winds).

The three warm patterns included extremely strong events with the largest warming near the South American coast, a cluster of weak warm events centered near the dateline, or moderate warming in the central-eastern equatorial Pacific. For strong El Nino events, the westerly wind bursts grew strong and extended east of the dateline.

According to the research team, the wind bursts affect ocean dynamics by exciting Kelvin waves that produce surface warming in the eastern equatorial Pacific and by generating strong equatorial surface currents that extend the eastern edge of the warm pool.

The study is published in the journal Nature Geoscience.