El Niño strengthening, but rain-boosting IOD could offset impact: Australia Met Bureau
However, meteorologists are hopeful of the emergence of a rain-boosting phenomenon – a positive Indian Ocean Dipole (IOD) – which could offset the impact of El Niño.
However, meteorologists are hopeful of the emergence of a rain-boosting phenomenon – a positive Indian Ocean Dipole (IOD) – which could offset the impact of El Niño and ensure monsoon to be normal this year.
Trade winds remain weakened and are likely to contribute to more warming of the tropical Pacific Ocean, the Australian weather bureau said. Other indicators such as cloudiness near the Date Line, the Southern Oscillation Index (which captures differences in sea level pressure) and sub-surface temperatures in the tropical Pacific Ocean are typical of an established El Niño.
The bureau said all international climate models surveyed by it indicated that El Niño would continue to strengthen, and persist into early 2016. Typically, El Niño peaks during the late austral spring (September-November) or early summer (December-February), and weakens in the following year.
But it said there was the possibility of a positive Indian Ocean Dipole, "with three of the five international models indicating a positive IOD is likely during late winter to spring".
IOD refers to differences in temperature between the western and eastern part of the Indian Ocean. A ‘positive’ IOD period, which indicates warmer water in western Indian Ocean or the Arabian Sea, tends to boost the monsoon. Weather scientists say it strengthened the monsoon in 2006.