赤道太平洋冷舌偏差对模式模拟和预估西北太平洋异常反气旋的影响

西北太平洋异常反气旋（NWPAC）是El Niño影响东亚气候的桥梁，也是东亚气候年际变率可预报性的主要来源，理解其在增暖情景下的变化对预估未来东亚气候年际变率的变化至关重要。然而模式对当前NWPAC的模拟以及未来NWPAC变化的预估均存在很大的模式间不确定性。前人研究表明赤道太平洋冷舌偏差能够影响模式预估未来太平洋气候态海温的变化，这有可能影响未来ENSO及其遥相关变化的预估。且预研究发现模式模拟的冷舌偏差的强弱与模式模拟的NWPAC强弱以及预估的未来NWPAC的变化之间存在显著的相关关系，但其中的机制尚不清楚。本项目拟利用多模式模拟和预估结果，研究冷舌偏差造成的气候态海温偏差对模式模拟和预估的El Niño异常海温的影响，进一步揭示模式间模拟和预估NWPAC差异性产生的主要海气相互作用过程。该项目有利于提高我们对东亚气候年际变率变化的理解，更好的应对气候变化，具有重要的科学意义。

The anomalous Northwest Pacific anticyclone (NWPAC) is a key bridge linking El Niño to the climate in East Asia and a primary predictor of the interannual variability of climate in East Asia. Understanding how this will change under global warming is crucial to project the changes in the interannual variability of climate in East Asia. However, many state-of-the-art climate models simulate the NWPAC in current climate and project the NWPAC changes in a warmer world with a large inter-model spread. Previous studies suggested that the excessive equatorial Pacific cold tongue bias disturbs the projection of sea surface temperature (SST) warming pattern, which may influence the projections of ENSO and its teleconnection. Moreover, our preliminary study finds that the simulated equatorial Pacific cold tongue strength is closely associated with the simulation of the NWPAC in current climate and the projections of the NWPAC in the future. However, the physical mechanisms connecting the excessive cold tongue bias and the simulated NWPAC in historical run and estimated NWPAC changes in future projections are not yet clear. In this project, we will investigate the effects of unrealistic SST mean state induced by the excessive cold tongue bias on the simulations and projections of El Niño by using multi-models. Further, we aim to reveal the main air-sea coupled processes of the multi-model uncertainty in simulating and projecting the NWPAC. This project will contribute to our understanding on the changes in the interannual variability of East Asia climate and play an important role in our response to global warming.