14 Feb. () –
Chinese researchers have found that greenhouse warming and internal variability The frequency of extreme El Niño events has increased since 1980.
The research, conducted by a team of scientists from the Institute of Atmospheric Physics (IAP) of the Chinese Academy of Sciences, has been published in the journal Nature Communications.
According to the researchers, El Niño has changed its properties since the 1980s, being characterized by more common extreme El Niño and Central Pacific El Niño events. However, it was not clear if this change was due to external causes or if it was part of natural variability.
The researchers studied past changes in El Niño diversity and quantified the contribution of anthropogenic forcing and internal variability to recently observed El Niño diversity, reports Xinhua.
They found that the frequency of extreme El Niño and Central Pacific El Niño events also increased during the period 1875-1905, when the anthropogenic concentration of carbon dioxide was relatively low.
They determined that the frequency of extreme El Niño and Central Pacific El Niño events since 1980 was due to a combination of anthropogenic forcing and internal variability associated with the Atlantic Multidecadal Oscillation (AMO).
The researchers revealed that a positive AMO increases the zonal gradient of sea surface temperatures in the Central Pacific, reinforcing zonal advective feedback and favoring the development of extreme El Niño and the Central Pacific.
“Understanding the observed El Niño variation can help to more accurately project future change,” said Huang Gang, corresponding author of the study and a researcher at the IAP.
