QBO影响和调制东亚冬季风的机理研究

Stratosphere-troposphere dynamical coupling research has been one of the international frontiers on the climate dynamics study. As a significant interannual variability signal of the climate system and one of the external forcing on the extratropical atmospheric system, the effect of QBO on the the characteristics and dynamic processes of the East Asian winter monsoon is the subject of the proposed research in this project. Based on the HT effect theory in recent years on the latest progress of this project, according to planetary wave propagation wave refraction index of the linear theory and wave-zonal flow interaction dynamics, we will make observational data analysis, dynamic diagnostics and run the dry atmospheric mechanism model to research the mechanism through the stratospheric polar vortex and the subtropical jet way, and to study the effect of dynamic process on the East Asian winter monsoon,to study the QBO's modulation of the planetary waves by El Nino on the dynamic process of the East Asian winter monsoon. It is important for us to better understand and predict the winter climate anomalies in China due to their scientific significance and application value.

平流层-对流层动力耦合是气候动力学研究国际前沿领域。作为气候系统显著年际变率信号和热带外大气系统外强迫因子之一的QBO，对东亚冬季风有何影响特征以及相关动力过程是本项目拟研究的课题。本项目在近年来HT effect理论研究最新进展上，根据行星波传播波折射指数线性理论和波流相互作用动力学，利用观测资料分析、动力诊断和干大气机制模式，研究QBO通过平流层极涡途径和副热带急流途径影响东亚冬季风的动力过程，研究QBO调制ENSO激发行星波影响东亚冬季风的动力过程。这对更好理解和预测我国冬季气候异常有重要科学意义和应用价值。

项目主要研究北半球冬季大气遥相关型的新观测和动力学机制。利用自组织映射方法对北半球冬季低频高度场进行聚类分析，新发现一类流型命名为西半球环流型。应用完整大气环流模式GFDL AM2和简单正压大气模式研究了西半球环流型的形成机制。指出热带西太平洋海表面温度强迫和基本气流的共同作用是西半球环流型成为大气内部模态的主要机制原因，研究还揭示热带外天气尺度波的反馈作用及下游发展对西半球环流也起到维持作用。项目还研究了MJO通过下游Rossby波和副热带急流的正压不稳定影响热带外太平洋-北美区域天气气候的物理机制。