'La Nina' to bring normal monsoons

The monsoon is likely to be normal this year. A positive indication to this effect came when the World Meteorological Organisation (WMO) confirmed that the threat posed to the monsoon by the dreaded El Nino is now over.

Instead, there is a substantial possibility of the emergence of La Nina, the opposite of El Nino, which invariably has a positive influence on the monsoon.

El Nino, a Spanish word that means Baby Christ, occurs when sea surface temperatures in the central and eastern tropical Pacific Ocean are substantially higher than normal. It has been found to have a substantial bearing on climate patterns around the world, including the south-west monsoon that is crucial for India.

La Nina occurs when sea surface temperatures in the central and eastern tropical Pacific Ocean are lower than normal. The most recent strong La Nina phase was witnessed between 1998 and 2001. The monsoon was normal in those years.

In its latest update on El Nino/La Nina, the WMO has categorically stated that the El Nino event of the latter half of 2006 has ended. "There are sufficient indications to suggest that a transition to La Nina has recently become a substantial possibility," it stated.

"The country has seldom experienced a drought in a La Nina year so far," said Akhilesh Gupta, advisor to the science and technology minister for the monsoon prediction modernisation project.

The India Meteorological Department (IMD) is firming up its long-range monsoon prediction, which it may announce next week. The developments on the El Nino front would constitute one of the significant inputs in this exercise, though the IMD's monsoon forecast models take into account several other local and global weather factors as well.

The emergence of El Nino in the latter half of 2006 had affected the climate in several regions, as reflected in drier than normal conditions across many parts of Australia, Indonesia and Fiji, unusually heavy rains and flooding across parts of eastern Africa, and extended dry spells across many south-western parts of southern Africa.

However, El Nino dissipated quite rapidly in January and February. By the end of February, sea surface temperatures in the Pacific regions were colder than normal, indicating an end of El Nino. "Currently, several, but not all, models indicate the likelihood of an emerging La Nina over the next several months," the WMO has pointed out.