热带平流层QBO对冬季ENSO热带外遥相关的调制及其机理研究

ENSO是热带地区年际尺度最重要的海气耦合现象，且可以通过激发热带外遥相关机制影响东亚和北美冬季气候异常。以往研究ENSO影响东亚和北美气候异常不稳定的机制时，主要侧重于海温信号和对流层大气环流的作用，基本上没有关注平流层大气环流的影响。QBO作为热带平流层大气环流变化的重要模态，针对QBO是否可以通过影响ENSO热带外遥相关进而调制ENSO对东亚和北美的冬季气候异常的科学问题，本项目拟利用多种观测数据和再分析资料，通过统计分析和动力诊断来研究冬季QBO对ENSO相关的热带外遥相关的调制作用，并揭示东亚和北美地区冬季气候的响应；进一步结合AMIP6模式模拟结果，通过系统性的比较分别从对流层和平流层来研究QBO调制ENSO影响东亚和北美气候的物理过程。项目预期成果不但对深入理解ENSO影响热带外气候异常的不稳定性及其机理有重要科学意义，而且为提高东亚和北美地区冬季气候预测水平提供科学基础。

ENSO is the predominant air-sea coupling phenomenon at the interannual timescale in the tropics. By changing tropical convective activities and associated diabatic forcing, ENSO stimulates tropical-extratropical teleconnections, and thus affects climate anomalies in East Asia(EA) and North America(NA) during boreal winter. Previous studies of the unstable relationships between ENSO and climate anomalies in EA and NA have focused primarily on the role of SST signals and tropospheric atmospheric circulation, with little attention to the effects of stratospheric atmospheric circulation. QBO is an important mode of atmospheric circulation variability in the tropical stratosphere. Regarding the scientific question of whether QBO can modulate ENSO's effects on winter climate anomalies in EA and NA by influencing ENSO teleconnections, this project proposes to investigate this issue through statistical analysis and dynamical diagnosis using multiple observational data and reanalysis data. This project aims to study the role of QBO in the modulation of ENSO-related extratropical teleconnections in winter and to reveal the climate response in EA and NA. Further incorporating the results of the AMIP6 model simulations, the physical processes by which QBO modulates ENSO’s remote effects on EA and NA climate are investigated through systematic comparative analysis from the troposphere and stratosphere, respectively. The anticipated results of the project are not only scientifically important for understanding the instability of ENSO's influence on extratropical climate anomalies, but also provide a scientific basis for improving winter climate prediction in EA and NA.