Scientists warn of a rare third year La Nina – Frustrated by it?

news7g10/21/2022

3 2 minutes read

Scientists warn of a rare third year La Nina - Frustrated by it?

ATMOSPHERIC INSTITUTE OF PHYSICS, CHINA ACADEMY

Arctic sea smoke — **PICTURE DESCRIPTION: ARCTIC SEA SMOKE NEAR QINGDAO, CHINA ON JANUARY 7, 2021 WHEN COLD SURGE HIT NORTH CHINA. RESULTS OF AIR IMAGES THROUGH WATER RELATED, PHENOMENON IS RARE, EVEN IN ART.** see more
CREDIT: SHAOQING WANG

El Niño – Southern Oscillation (ENSO) is an irregular cyclic variation in wind and sea surface temperatures over the tropical eastern Pacific that affects the climate of much of the tropics and subtropics. This natural phenomenon is important to study because of the socioeconomic impacts it can have on issues such as food security, agricultural production, human health and water resources. to mention a few.

With a preference characteristic that peaks during severe winters and decays rapidly in spring (known as “phase lock”), and oscillates roughly every 2–7 years, historically, ENSO rarely persists for long in either its cold (La Niña) or warm (El Niño) phases. Since the turn of the current century, however, three so-called “double” La Niña events have occurred, in 2007–09, 2010–12 and 2020–22.

This succession of double La Niña events is compelling enough in itself; but for now, based on updated data from several institutions issued in April 2022, it looks like the current event is likely to continue throughout the summer and fall of 2022, suggesting the probability of a third year La Niña extending from 202023.

“This will be the first third year of La Niña since the 1998–2001 event, the only event observed since 1980,” explains Dr. Xianghui Fang from Fudan University, China.

By examining the state of the atmosphere-ocean system over the tropical Pacific in March 2022, Fang and his collaborator, Professor Fei Zheng, from the Institute of Atmospheric Physics, Academy of Sciences China, found that the central equatorial to eastern Pacific Ocean maintained colder-than-normal conditions and that southeasterly winds over the equatorial Pacific were substantial.

The team analyzed the possible contributions of four physical factors related to the heat path (the boundary between warmer seawater at the surface and cooler water below) and surface winds during the La Niña year. these three potentials. Historically, atmospheric variables in the spring of 2022 suggest that southeast and southeast winds will reach their largest amplitudes since 1980, supporting the emergence of a third-year La Niña.

The team further discusses the possible global climate impacts of this impending third year La Niña event in a News & Views article published on Advances in Atmospheric Science. Specifically, they examine the only two similar events in history, in 1973–1976 and 1998–2001, and based on similarities and differences, conclude that there is much uncertainty in predicting the future. predict the climate effects of the current event, both in terms of summer precipitation and winter temperatures.

“However, we should watch out for the possibility of intense cold surges in Eurasia, which could create more extreme cold events in east or northeast China,” warns Fang.