Climate Change

‘Double-dip’: La Nina has formed for second year in a row, says NOAA   

A La Nina usually causes wetter conditions and also leads to formation of low-pressure areas in India

 
By DTE Staff
Published: Tuesday 19 October 2021
Cooler-than-average sea surface temperatures along the equator is indicative of La Nina in the tropical Pacific Ocean in September 2021. Photo: NOAA
Cooler-than-average sea surface temperatures along the equator is indicative of La Nina in the tropical Pacific Ocean in September 2021. Photo: NOAA Cooler-than-average sea surface temperatures along the equator is indicative of La Nina in the tropical Pacific Ocean in September 2021. Photo: NOAA

A La Nina system has formed for the second year in a row, according to the Climate Prediction Center of the National Oceanic and Atmospheric Administration (NOAA), a recent statement said.

The latest La Nina is expected to last through the early spring of 2022 (February), the NOAA statement said. Previous La Ninas occurred during the winter of 2020-2021 and 2017-2018. An El Nino developed in 2018-2019.

Two La Ninas happening one after the other (with a transition through ENSO neutral conditions in between) is not uncommon. It is usually referred to as a ‘double-dip’. In 2020, La Nina developed during the month of August and then dissipated in April 2021 as ENSO-neutral conditions returned, the statement said.

Mike Halpert, deputy director of NOAA’s Climate Prediction Center, said:

Our scientists have been tracking the potential development of a La Nina since this summer and it was a factor in the above-normal hurricane season forecast, which we have seen unfold.

“The La Nina will influence our upcoming temperature and precipitation outlooks,” he added.

La Nina is a natural ocean-atmospheric phenomenon. It is marked by cooler-than-average sea surface temperatures across the central and eastern Pacific Ocean near the equator. It means ‘little girl’ in Spanish.

It is the opposite of El Nino (meaning ‘little boy’), that is marked by warmer-than-average sea surface temperatures across the central and eastern Pacific Ocean near the equator.

Both, La Nina and El Nino are part of the El Nino Southern Oscillation (ENSO) cycle. ENSO is characterised by opposing warm and cool phases of oceanic and atmospheric conditions in the tropical Pacific Ocean.

El Nino usually causes a decrease in precipitation and has been found to cause drought-like conditions in India. On the other hand, La Nina causes an increase in precipitation. It also causes formation of low-pressure areas.

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