El Nino to continue developing in Pacific

 

 

Ocean conditions in the Pacific Basin remain at levels consistent with an El Nino climate episode, but the recent positive values of the Southern Oscillation Index, or SOI, are unusual - a persistent, negative SOI is one of the hallmarks of El Nino events, the government's Bureau of Meteorology said Friday (July 31).

 

"Six of the seven international coupled climate models surveyed here are predicting that Pacific Ocean sea surface temperature in the outlook period will remain above El Nino thresholds throughout most of the second half of 2009," the bureau reported in a monthly review of guidance from its computer models.

 

Given the high level of persistence and hence predictability of Pacific Basin conditions in the calendar second half, "the probability of an El Nino event continuing to develop and maturing late in 2009 is high," it said.

 

In its most recent full report, the bureau said its SOI posted a strongly positive value of plus 12 in the 30 days ended July 20, up from a monthly value in June of minus 2 and up from minus 12 at times in May and June.

 

More recently, as the bureau predicted, the SOI has started falling and July 29 measured plus 2.2, according to bureau data.

 

The bureau is scheduled to issue its full analysis of El Nino indicators Wednesday.

 

El Nino usually refers to the extensive warming of the central and eastern Pacific and cooling in the western Pacific.

 

 

Dry weather associated with El Niños in 2002 and 2006 helped slash Australian wheat output to 10.1 million tonnes and 10.8 million tonnes, respectively.

 

But an El Nino in 1997 was quite benign, and wheat output in 1997-98 was 19.2 million tonnes, just below the current long-term annual average of 19.5 million tonnes, according to official data.