Diagram of the Walker Circulation, a vast loop of air above the equatorial Pacific Ocean. (Illustration: Gabriel Vecchi, UCAR)

55pc probability of 'strong or extraordinary' El Niño, estimates ENFEN

PERU
Tuesday, September 01, 2015, 23:50 (GMT + 9)

The Multi-sector Committee in charge of the National Study of El Niño Phenomenon (ENFEN) estimates that there is a 55 per cent probability that this weather phenomenon reaches a strong or extraordinary extent, with similar events to those observed in the summer in 1982-1983 and 1997-1998, when El Niño took place.

In its latest statement, the ENFEN also indicates that it has estimated a 95 per cent chance that the coastal El Niño phenomenon continues during the 2015-2016 summer, and 20 per cent probability of occurrence with an extraordinary extent.

However, the agency points out that there is still a 95 per cent likelihood that the event will have a "weak or greater" magnitude.

The ENFEN explains that although now typical conditions of a strong coastal El Niño event have been noted, there is no guarantee that the conditions persist with the same intensity until the summer.

In addition, it states that the observed ocean-atmosphere conditions and the forecasts for the central Pacific suggest a high probability that El Niño in this region has strong or very strong magnitudes. However, it clarifies that it is likely that global climate models (GCMs) are overestimating these probabilities, as they did in 2012 and 2014, possibly because they are not adequately representing the effects of decadal phases.

"For a strong or extraordinary El Niño event to develop in the summer, apart from warming, it should be sufficiently high to activate the convective feedback processes in the eastern Pacific," the report describes.

Finally, the ENFEN clarifies that "these probabilities must be updated as the system evolves," due to the uncertainty associated with the decadal variability, observational and modeling constraints and imperfect scientific knowledge.

In this context, the Minister of Production, Piero Ghezzi, said in press statements that the annual catch quota in Peru will not be affected with the arrival, in late December, of El Niño phenomenon, as it has already been covered and 2.9 million tonnes were captured, 30 per cent more than in 2014.

Ghezzi clarified the anchovy catch that is made in the second fishing season during the arrival of El Niño will be additional to the figure achieved, and predicted that they consider an earlier season.

Related articles:

- El Niño increases availability of some marine species
- Anchovy biomass begins to feel El Niño impact

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