| Autor: |
Chen, Shaowen1,2 (AUTHOR), Chen, Shangfeng2,3,4 (AUTHOR) chenshangfeng@mail.iap.ac.cn, Jin, Jiangbo1,2 (AUTHOR) jinjiangbo@mail.iap.ac.cn, Zheng, Yuqiong5 (AUTHOR), Chen, Wen5 (AUTHOR), Zheng, Tao6 (AUTHOR), Feng, Tao7 (AUTHOR) |
| Abstrakt: |
The North Pacific Meridional Mode (PMM) is the strongest interannual air‐sea coupled system in the subtropical northeastern Pacific, which can significantly impact the development of El Niño and Southern Oscillation (ENSO). This study examines performance of the second version of the Chinese Academy of Sciences Earth System Model (CAS‐ESM2), developed primarily at the Institute of Atmospheric Physics, Chinese Academy of Sciences (IAP/CAS), in simulating the PMM, ENSO, and their relationship. It reveals that CAS‐ESM2 can well reproduce the tropical climate mean states, including sea surface temperature (SST), surface winds, and precipitation. Furthermore, the model shows a good ability in reproducing the seasonal evolutions of the PMM and ENSO. Moreover, CAS‐ESM2 effectively simulates the influence of the PMM on subsequent ENSO and the underlying physical mechanisms, including the wind‐evaporation‐SST feedback process, the trade wind charging mechanism and summer deep convection mechanism. However, some improvements are still needed, particularly in representing the periodicity of the PMM, an overestimation of the ENSO intensity and westward extension of ENSO‐related SST anomalies in the tropical Pacific. The results obtained from the CAS‐ESM2 showcase significant progress in understanding the interaction between air‐sea interaction systems over the tropics and subtropics. Plain Language Summary: El Niño and Southern Oscillation (ENSO) is the strongest interannual atmosphere‐ocean coupling variability in the tropical Pacific. ENSO can trigger extreme weather and climate events worldwide, and lead to substantial economic losses. While tropical processes are acknowledged to influence ENSO, many recent studies have emphasized the important role of extratropical air‐sea variabilities in modulating the occurrence and development of ENSO events. The Pacific Meridional Mode (PMM) has been identified as a key channel in transmitting the impact of extratropical forcing on ENSO. Therefore, it is crucial to evaluate the performance of current climate models in representing the PMM and its relationship with the ENSO. This evaluation holds significant scientific value as it can enhance our understanding of the dynamics underlying the ENSO and help improve the prediction of ENSO. The second version of the Chinese Academy of Sciences Earth System Model (CAS‐ESM2), developed primarily at the Institute of Atmospheric Physics, Chinese Academy of Sciences, represents a significant milestone in advancing atmospheric science in China. This study aims to assess the capabilities of CAS‐ESM2 in simulating the ENSO, PMM, and the impact of PMM on ENSO. Our findings indicate that CAS‐ESM2 well reproduces these two air‐sea coupling systems and captures their relation. Key Points: Chinese Academy of Sciences Earth System Model (CAS‐ESM2) has eliminated the double Intertropical Convergence Zone bias to some extentCAS‐ESM2 can reasonably well simulate the spatial‐temporal features of Pacific Meridional Mode (PMM) and El Niño and Southern Oscillation (ENSO)The influence of the spring PMM on ENSO and the underlying mechanism can be captured by the CAS‐ESM2 [ABSTRACT FROM AUTHOR] |
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