No consensus among climate centres on duration, strength of phenomenon this time round
AMANDA LEE Today Online 14 May 15;
SINGAPORE — With several Pacific Rim countries declaring in the past few days that El Nino is here, the Meteorological Service Singapore (MSS) has said the Republic is more likely than not to experience weak El Nino conditions in the coming weeks.
Based on its assessment of model outlooks from international climate centres, there is a 60 to 70 per cent chance of that happening, it said, in response to TODAY’s queries.
But the agency was also quick to lodge the caveat that predictions could be off the mark, given that existing models, at this time of the year, cannot “skilfully” capture El Nino.
El Nino, which comes along every two to seven years, is the abnormal warming of the tropical Pacific Ocean, which can potentially wreak havoc with weather conditions. In the case of South-east Asia, it can lead to prolonged drier and warmer weather.
On Tuesday, the Australian Bureau of Meteorology joined the United States Climate Prediction Center and Japan Meteorological Agency in declaring that sea-surface temperature in the equatorial Pacific are high enough — and the atmosphere above the ocean has reacted strongly enough — to signal that an El Nino has begun, reported Bloomberg.
However, there is no consensus on the duration and strength of the phenomenon this time round.
For instance, the Australians forecast a “substantial” event later in the year, but conceded it was too early to say for sure how strong it could be.
Dr David Jones, manager of Climate Monitoring and Prediction at the Australian bureau, has said “all of our model guidance predicts it’s going to continue to strengthen. A significant or substantial event is likely”.
The US centre’s deputy director, Mr Mike Halpert, however, said last week that he was not ready to make a prediction on strength yet.
Models have been struggling to predict with certainty the intensity of each event. A strong event was expected last year, but failed to materialise.
That each agency has its own criteria for El Nino is another reason for the lack of consensus.
In its reply, the MSS said some “sporadic warm anomalies of sea-surface temperatures have been observed in nearby seas in recent months”, but added that there is “no reason” to associate these with the developing El Nino conditions.
“The impact of these sea-surface temperature anomalies on local and regional weather patterns on seasonal time scales is not as established as the El Nino sea-surface temperature anomaly in the tropical Pacific Ocean,” it explained.
Commenting on the possible impact from an El Nino event, Assistant Professor Winston Chow from the National University of Singapore’s Geography Department said a strong event is usually linked to drier conditions in Singapore and other South-east Asian countries.
For example, Singapore recorded one of the lowest annual rainfalls in 1997, which corresponded with one of the strongest El Nino events. There was 53 per cent less rainfall from June to September that year.
Food supplies could also be disrupted: The last El Nino in 2009 brought the worst drought in nearly 40 years to India, cutting rice output in the world’s second-largest producer by 10 million tonnes and pushing global sugar prices to the highest in nearly three decades.
