Team evaluates CMIP6 climate models that simulate multiyear El Niño events

A research team has evaluated a collection of climate models to better understand how well they can simulate multiyear El Niño events and their impact on spring precipitation over southern China. Their study showed that while many climate models can reproduce the multiyear El Niño events, most of them struggle to simulate their impacts on southern China’s spring precipitation.

Their work is published in the journal Ocean-Land-Atmosphere Research on December 16, 2025.

Multiyear El Niño events have become more frequent in recent decades. They impact the climate in markedly different ways than single year El Niño events. El Niño is one phase of the larger El Niño-Southern Oscillation, a recurring climate pattern in the tropical Pacific Ocean.

The spring precipitation over southern China following multiyear El Niño events is greater than the precipitation during single-year events. Yet the ability of current climate models to simulate these events and their associated regional impact is uncertain. “The core problem was that it remained unclear whether current CMIP6 climate models could accurately simulate these multi-year events and, more importantly, capture the related atmospheric circulation and precipitation responses over southern China during the second year of these events,” said Xiaoman Zhang, a master’s student at Sun Yat‐sen University and Southern Marine Science and Engineering Guangdong Laboratory.

The research team undertook their study using 39 Coupled Model Intercomparison Project Phase 6 (CMIP6) models. These CMIP6 models are a group of advanced global climate models that come from research centers around the world. They simulate past and future climate change. “We aimed to better understand how well current CMIP6 climate models can simulate multiyear El Niño events and their associated impacts on spring precipitation over southern China,” said Xiaoming Hu, a professor at Sun Yat-sen University, and Southern Marine Science and Engineering Guangdong Laboratory. The team assessed the performance of the 39 CMIP6 models in simulating multiyear El Niño events. Their study covers the period from 1950 to 2014, studying the spring precipitation in the following years.

Southern China is a densely populated and economically developed region that is vulnerable to frequent droughts and floods. The spring precipitation there accounts for more than 30 percent of the total annual precipitation in the region. The variability of the spring rainfall from year to year increases the risks of drought and flood. This variability presents challenges for farming and water resources management.

The team’s evaluation of the 39 CPMIP6 models showed that most models can capture the general occurrence of multiyear El Niño events and their impact on spring precipitation over southern China. However, the climate models are not as successful in reproducing the associated spring precipitation anomalies.

The team did note that the Energy Exascale Earth System Model version 1.0 (E3SM-1-0) is the only model that reproduces the observed increase in precipitation over southern China and simulates realistic water vapor transport and convergence-related uplift. However, even that model fails to accurately simulate the large-scale circulation anomalies connected with these events.

Only a few models were able to capture both the observed precipitation pattern and the associated large-scale circulation anomalies, such as changes in the western North Pacific anticyclone. This indicates substantial inter-model differences in representing the underlying physical mechanisms. As a result, uncertainties in simulating multiyear El Niño teleconnections may limit the reliability of regional climate projections and seasonal predictions based on current climate models.

“The key message of this study is that while many CMIP6 models can reproduce the occurrence of multiyear El Niño events, most of them struggle to realistically simulate their impacts on spring precipitation over southern China,” said Meng Li, a meteorological engineer at Handan Meteorological Bureau.

Looking ahead, the team wants to investigate the physical mechanisms responsible for the model performance differences, particularly why some models outperform others in simulating multiyear El Niño impacts. This would include examining air-sea coupling processes, tropical Pacific sea surface temperature evolution, and atmospheric circulation responses. “Ultimately, our goal is to improve the representation of multiyear El Niño-Southern Oscillation events and their teleconnections in climate models. This work will help provide more reliable climate information for assessing regional impacts, reducing disaster risks, and supporting climate adaptation, particularly in East Asia,” said Zhang.

The team includes Xiaoman Zhang, Wenxiu Zhong, and Xiaoming Hu, Sun Yat-sen University and Southern Marine Science and Engineering Guangdong Laboratory; Qingquan Li, National Climate Centre, Beijing, and Nanjing University of Information Science and Technology; Meng Li, Handan Meteorological Bureau; and Yunqi Kong, Guangdong Ecological Meteorological Centre.

This research is funded by the Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai).