夏季海洋性大陆越赤道气流季内振荡与西太大气对流和环流之间的相互作用关系

Various previous studies demonstrated that the cross-equatorial flows over the Maritime Continent (MC-CEF in short) in summer exhibit the variability of multi timescales from intraseasonal oscillation to interdecadal variation, and affect significantly the climate in China. However, relative to the other timescales, the intraseasonal oscillations of MC-CEF have not been well understood. Based on previous results, we hypothesize that the intraseasonal oscillations of MC-CEF might be closely related to the atmospheric convection over the tropical western Pacific. To check this hypothesis, this study aims to examine the intraseasonal oscillations of MC-CEF and their interaction with the atmospheric convection, subtropical high and monsoon trough over the tropical western Pacific. The results may be helpful for better understanding of relationships between the individual components of East Asian summer monsoon system.

大量的研究结果表明，夏季海洋性大陆越赤道气流（或称澳大利亚越赤道气流）呈现出从季内振荡到年代际的多时间尺度变化特征，并对我国气候具有重要的影响。然而，相对于其他时间尺度，目前对其季内振荡的特征和机理却不清楚，有待研究。基于以往的研究结果，我们推测海洋性大陆越赤道气流的季内振荡和热带西太平洋大气对流关系密切。围绕着这一推测，本项目拟研究海洋性大陆越赤道气流的季内振荡特征及其与西太大气对流、副高、季风槽之间的相互作用关系，研究结果可以使我们可以更深入地认识东亚夏季风系统组成成员之间的相互联系。

夏季海洋性大陆越赤道气流呈现出从季内振荡到年代际的多时间尺度变化特征，并对我国气候具有重要的影响。项目立项和执行以来，本项目按照计划分析了海洋性大陆越赤道气流的垂直结构，明确了高低层越赤道气流之间的反相关关系，利用多套再分析资料探讨了与越赤道气流相关联的热带异常及关键物理过程，并结合简单线性斜压模式及大气环流模式揭示了可能的物理机制。该项目取得的科研成果不仅加深了对越赤道气流多时间尺度变化规律的认识，还可以提高对东亚和西北太平洋天气气候变异的理解。