AsianScientist (Dec. 4, 2017) – In a study published in Advances in Atmospheric Sciences, scientists in China have developed a climate model to better predict the arrival and effects of the central and eastern Pacific El Niño.
In recent years, a new type of El Niño, called the central Pacific (CP) El Niño, has emerged, in which maximum sea surface temperature (SST) anomalies arise in the central Pacific, unlike the conventional El Niño wherein the maximum SST anomalies are located in the eastern Pacific (EP El Niño). The more frequent occurrence of the CP El Niño and its different impacts on global climate compared to EP El Niño have been well documented.
However, a systematic examination of the performance of climate models in predicting the two types of El Niño had yet to be undertaken, and it remained controversial as to whether the predictability differs among state-of-the-art climate models.
In this study, a team of scientists led by Professor Zheng Fei of the Institute of Atmospheric Physics (IAP), Chinese Academy of Sciences, China, and Professor Yu Jinyi from the University of California, Irvine, explored the ability of the IAP’s El Niño–Southern Oscillation (ENSO) ensemble prediction system to accurately forecast the two types of El Niño, focusing on the nine EP El Niño and 12 CP El Niño events that have occurred since 1950.
“We found that the skill scores for EP events were significantly better than those for CP events at all lead times,” said Zheng. “The possible reasons are related to the systematic forecast biases coming mostly from the prediction of CP events, as well as the systematic error characterized by an overly warm EP during the spring season, indicating a stronger spring prediction barrier for CP El Niño.”
Further improvements to coupled atmosphere-ocean models in terms of CP El Niño prediction should be recognized as a key and high-priority task for the climate prediction community.
The article can be found at: Zheng & Yu (2017) Contrasting the Skills and Biases of Deterministic Predictions for the Two Types of El Niño.
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Source: Chinese Academy of Sciences; Photo: Shutterstock.
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