Oceanographers and atmospheric scientists are predicting a stronger-than-usual El Niño for the end of 2023.
Already predicted to occur later this year, the research by oceanographers based in China may add greater clarity to forecasts by studying Pacific Ocean heat content and other atmospheric disturbances.
Such disturbances are known as high-frequency perturbations. They include westerly wind bursts and easterly wind surges, which influence El Niño intensity.
Regardless of these influences, the volume of warm water within the Pacific has reached levels not seen since last century.
“The upper ocean heat content in the winter of 2022 ranks the largest over the past 40 years,” says Professor Tao Lian from China’s Second Institute of Oceanography.
“Since the heat content serves as a primary precursor for an upcoming El Niño, we showed by a set of model experiments that within the low-frequency atmosphere-ocean coupling, the current heat content is sufficient for boosting a strong El Niño toward the end of 2023.”
The last climate driver update from Australia’s Bureau of Meteorology suggests a 50% chance El Niño will emerge in winter, as indicated by all but one of the models used to predict El Niño–Southern Oscillation (ENSO) activity. The National Oceanic and Atmospheric Administration, USA, considers there to be a 62% chance of El Niño formation.
ENSO activity can lead to either El Niño or La Niña events, the latter recently characterised in Australia by a three-year event that brought flooding rains to much of eastern Australia.
In contrast, El Niño events typically result in hotter and drier conditions for the same part of Australia which can potentially present an increased risk of heatwaves and bushfires.