东亚冬夏季风的TBO循环过程与机理研究

Tropospheric biennial oscillation (TBO) is not only the basic signal of tropical coupled air sea system in the Asian-Australian monsoon region, but the key feature of interannual linkage between East Asian winter and summer monsoons (EAWM-EASM). Based on a significant biennial association between EAWM-EASM and the tropical Indo-Pacific warm pool (IPWP), by performing various statistical methods such as season-reliant EOF, bandpass filtering and linear regression, this project firstly investigate biennial evolution of oceanic and atmospheric components, and apply involved theories to make a diagnosis about air-sea coupling within the IPWP region; secondly analyze and simulate temporal evolution and meridional propagation of biennial air-sea signal inside the EAWM-IPWP-EASM region, so as to find out atmospheric interaction between middle and low latitudes in the TBO Cycle of EAWM-EASM; finally identify TBO-related air-sea signal outside the EAWM-IPWP-EASM region, and investigate impact of outside forcing factors (such as ENSO, et al.) on the TBO cycle of EAWM-EASM. The successful development of this project will disclose physical processes and mechanisms of the TBO cycle associated with strong or weak East Asian winter and summer monsoons, and build the TBO conceptual model linked with EAWM, IPWP and EASM, which give a great push for a reliable prediction of East Asian monsoon system.

对流层准两年振荡（TBO）既是亚澳热带季风区海气耦合的基本信号，也是东亚冬夏季风年际循环的主要特征。基于准两年时间尺度上东亚冬夏季风与热带印太暖池显著关联的事实，本项目拟采用S-EOF、带通滤波、线性回归等现代统计方法，剖析热带印太暖池海气系统各物理量的准两年演变规律，结合有关理论诊断研究东亚冬夏季风TBO循环过程中的暖池海气相互作用；分析与模拟关键区（东亚季风-印太暖池区）TBO信号的季节演变和经向传播特征，认识东亚冬夏季风TBO循环过程中的中低纬相互作用；分析研究关键区（东亚季风-印太暖池区）内TBO信号与关键区外海气信号的关联性，探讨外强迫因子（如ENSO等）对东亚冬夏季风TBO循环的可能影响。此项目的实施，旨在揭示东亚冬季风和夏季风强弱交替的TBO循环机理，建立东亚冬季风-印太暖池-东亚夏季风的TBO概念模型，为检验和改善东亚季风的模拟与预报能力提供理论依据。

本项目旨在揭示东亚冬夏季风准两年变化循环（TBO）的关键物理过程。首先，收集1979-2013年的逐月观测资料和再分析资料，使用20-30月的带通滤波器构建项目所需的TBO资料数据集；其次，基于TBO资料库剖析东亚季风-印太暖池关键区TBO 信号的季节演变和经向传播特征，辨识东亚冬夏季风TBO 循环的两个主导模态及其相关联的暖池区海气耦合和中低纬相互作用；最后，针对东亚季风TBO循环主导模态的季节演变过程进行模拟，探讨东亚季风-印太暖池关键区内TBO信号与关键区外海气信号的关联性，认识东亚冬夏季风TBO循环主模态的外强迫因子。此外，本项目还超额探讨了以下内容：中国汛期暴雨的年代际跃变及其大尺度环流背景；春季印缅槽的年代际增强及其气候影响等。相关研究成果已完成学术论文6篇：发表CSCD论文2篇，发表SCI论文2篇，在审SCI论文2篇。