TEHRAN- According to the latest data, the rapidly growth of El Niño anomaly is expected to have a strong impact on increasing precipitation, Ahad Vazifeh, the head of the National Center for Drought and Crisis Management, has said.

“Statistical research has shown that during the El Niño phase, the accumulated precipitation in autumn in Iran is usually normal or above normal,” he added, Mehr reported.

“Conversely, rainfall patterns during La Niña tend to be less than normal in most of the country's provinces.”

He pointed out that over the last three years up to the end of the past Iranian calendar year (March 20), moderate La Niña conditions prevailed in the equatorial Pacific Ocean, and the rainfall amount in autumn was significantly less than normal.

“This year, the conditions of El Niño Southern Oscillation, known as ENSO, are special, and unlike the past, this index did not enter the neutral phase. The cycle is moving from a three-year la Niña straight into an El Niño.”

The National Center for Drought and Crisis Management has forecasted during the coming autumn and winter, the country will likely face a moderate El Niño event.
In case of being accompanied by other effective factors, it will cause normal precipitation in different regions and heavier than normal rainfall, especially in the western half of the country.

It should be noted that "El Nino" is one of the world's famous weather cycles that causes great anomalies in the climate of the entire planet every 2 to 7 years.

'El Niño' and 'La Niña'

'El Niño' or “the boy” is widely used to describe the warming of sea surface temperature that occurs every few years, typically concentrated in the central-east equatorial Pacific.

'La Niña' or "the girl" is the term adopted for the opposite side of the fluctuation, which sees episodes of cooler than average sea surface temperature in the equatorial Pacific. 

Of course, other factors also affect the decrease or increase of the average air temperature in the world, but the change of temperature in the Pacific Ocean is both highly predictable and has a very large scale compared to other indices, Vazifeh said in June.

“For this reason, it is one of the most important indicators used for numerical modeling in seasonal forecasts.”

“As much as the El Niño phase is stronger this year, the average winter temperature of this year in many countries, including in Iran, will record higher figures than normal conditions.”

“In 2016, when a very strong El Niño occurred, the temperature in different parts of the world recorded very high figures, and 2016 was the hottest year among all the years that the temperature of the earth has been measured and recorded,” he noted.

Iran has a dry and semi-arid climate and has an annual rainfall of 250 mm, which is about one-third of the global average.

The average rainfall of the country has been decreasing over time so the average rainfall of the country for 53 years was about 250 mm, but the average of the last 13 years has decreased to 232 mm.

MT/MG