New supercomputer model predicts 2012 seasonal climate

February 01, 2012
APAC weather map

Here is the Asia Pacific 2012 seasonal weather forecast: Japan is set for a warm spring and the south of the country will by dryer than normal this summer, with lower than average rainfall also affecting eastern China. The Indian sub-continent will experience a weaker summer monsoon but meanwhile, in Indonesia and Australia, the winter rains will be heavier than normal.

Will these predictions turn out to be true? Professor Toshio Yamagata, head of the Application Laboratory at Japan Agency for Marine-Earth Science and Technology (JAMSTEC), is pretty sure they will be, based on the extremely sophisticated model he has developed of climate variations in the Pacific and Indian Oceans. At the start of 2011 this pointed to the massive flooding that Thailand and Cambodia experienced later in the year.

Yamagata's supercomputer-driven modelling show a direct link between recently discovered climate variation phenomena in the Pacific and Indian Oceans and weather patterns in those vast areas. These directly impact a wide range of economic and security issues for nations bordering the Pacific and Indian Oceans. Industrial applications of these long-term weather and ocean forecasts are expected soon.

Indian Ocean

The professor used the JAMSTEC giant Earth Simulator supercomputer - one of the fastest on the planet - to develop his new model of climate change, which that combines meteorology and oceanography. Supported by his own version of a complex atmosphere-and-ocean-based model (the SINTEX-F1 coupled general circulation model), he discovered and confirmed the new phenomenon in the Indian Ocean that is similar to the El Nino and La Nina phenomena in the Pacific Ocean.

As the newly discovered phenomenon oscillates between positive and negative sea surface temperature patterns, he named it "Indian Ocean Dipole" (IOD). By using the Earth Simulator to run his new model of climate variations, the group led by Yamagata succeeded in making the world's first prediction of the IOD event in 2006.

Based on this research, Yamagata predicted last year's floods in Thailand. "In 2011, we observed both the IOD in the Indian Ocean and La Nina in the Pacific Ocean. When we see the IOD pattern, we can expect heavy rain over Indo-China. And La Nina also brings heavy rain in this region, so it was likely that the region would receive a double punch of torrential rain. Actually, our model predicted that." he said.

The IOD phenomenon is quite similar to El Nino, which occurs in the tropical region of the Pacific Ocean. In the IOD, the surface temperature of the ocean begins to drop in the eastern Indian Ocean (off the coast of Java), while it rises from the central to the western Indian Ocean (extending to the coast of Kenya). In response to these oceanic temperature changes, the easterly wind at the equator becomes stronger. This IOD phenomenon usually develops in May or June, reaches a peak in October, and fades away in December.