MJO、AO、ENSO的协同作用对东亚冬季次季节尺度天气/气候异常的影响

“次季节预报”越来越受到国内外科研和业务部门的关注。热带大气季节内振荡（MJO）和北极涛动（AO）是次季节预报重要的可预报性来源，而厄尔尼诺/南方涛动（ENSO）提供了海-气系统在年际尺度上最重要的变率背景。在次季节尺度变率的研究和预报中，需要在“天气-气候”界面上，考虑MJO、AO、ENSO的协同作用对次季节尺度变率的影响。目前，关于MJO、AO、ENSO对天气气候影响的研究大多是针对各自时间尺度，而将年际尺度的ENSO变率与MJO、AO的次季节尺度变率联系起来，探讨三者的协同作用对次季节时间尺度气候异常的影响鲜有研究。项目通过诊断分析，分析三者不同位相配置下，东亚冬季温度、降水和寒潮过程在次季节尺度上的变化特征；研究三者协同作用对东亚冬季极端事件的影响；揭示三者协同作用调制东亚冬季次季节尺度天气/气候异常的物理机制。研究成果有望应用于目前的次季节尺度预测分析业务。

Subseasonal prediction attracts more and more attention both in research and in operational fields. The tropical intraseasonal oscillation (MJO) and the Arctic oscillation (AO) are two of important predictability sources for subseasonal prediction; meanwhile, the El Niño/south oscillation (ENSO) provides the background of the interannual variability of the air-sea system. For subseasonal prediction, the cooperative effect of the MJO, AO and ENSO should be considered on the "weather-climate" interface. At present, most studies focus on the individual impact of the MJO, AO or ENSO on weather/climate. So, few studies have been made for the modulation of their cooperative effect on the winter weather/climate of the East Asia on the subseasonal time scales by relating the ENSO varability with the MJO and AO variability. This project will analyze the variation characteristics of rainfall, temperature and cold surge over East Asia on the subseasonal time scales with different phase combination of the MJO, AO, ENSO, and disclose the physical mechanism of the modulation of the cooperative effect of MJO, AO, ENSO on winter weather/climate over the East Asia, especially on the extreme climate events. Study fruits could be applied in present sub-seasonal forecast operation.