Origins of the Intraseasonal Variability of East Asian Summer Precipitation
Origins of the Intraseasonal Variability of East Asian Summer Precipitation
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DOI：
10.1029/2021gl096574
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发表时间：
2022-02
影响因子：
5.2
通讯作者：
Qiaoling Ren;Fei Liu;Bin Wang;Song Yang;Hui Wang;Wen-jie Dong
中科院分区：
文献类型：
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作者：
Qiaoling Ren;Fei Liu;Bin Wang;Song Yang;Hui Wang;Wen-jie Dong
准确的东亚夏季降水（EASP）的亚季节预测需要深入了解其季节内变化（ISV）的起源。然而，从本地过程，热带季节内振荡（ISO），和热带外影响的相对贡献EASP ISV仍然未知。我们进行了一系列数值试验，采用网格轻推方法确认中高纬波列和热带ISO的外部强迫作用，并量化它们的相对贡献。社区地球系统模型可以再现真实的EASP ISV和相关的先前信号。热带和中高纬强迫分别占EASP两个主要ISV模态总方差的53%和40%。热带强迫对两个主要模态的贡献（分别为31%和40%）比热带外强迫（24%和15%）更显著。这些外部强迫主要影响EASP区域平均值，而不是本地（网格）尺度的值。
Accurate subseasonal prediction of East Asian summer precipitation (EASP) requires a deep understanding of the origins of its intraseasonal variability (ISV). However, the relative contributions to the EASP ISV from local processes, tropical intraseasonal oscillation (ISO), and extratropical influence remain unknown. We conducted a set of numerical experiments with a grid nudging method to confirm the roles of external forcing from mid‐to‐high latitude wave trains and tropical ISO and quantify their relative contributions. The Community Earth System Model can reproduce realistic EASP ISV and associated preceding signals. The tropical and mid‐to‐high latitude forcings account for, respectively, 53% and 40% of the total variance for the two leading ISV modes of EASP. The tropical forcing contributes more significantly to the two leading modes (31% and 40%, respectively) compared to the extratropical forcing (24% and 15%). These external forcings mainly affect EASP regional averages rather than the values of local (grid) scale.