The influence of the Atlantic multidecadal oscillation on the interdecadal variability of winter precipitation in the Greater Mekong Subregion
The influence of the Atlantic multidecadal oscillation on the interdecadal variability of winter precipitation in the Greater Mekong Subregion
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DOI：
10.1002/joc.7117
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发表时间：
2021-04
期刊：
影响因子：
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通讯作者：
S. Gui;Ruowen Yang;Jie Cao;Shucheng Tan;S. Janjai;Zeyu Dong
中科院分区：
文献类型：
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作者：
S. Gui;Ruowen Yang;Jie Cao;Shucheng Tan;S. Janjai;Zeyu Dong
在这项研究中，我们调查了1892年至2016年大湄公河次区域（GMS）冬季降水的年代际变化（IDV）。结果表明，大湄公河次区域降水IDV主要表现为南、北方相反的变化特征。这种IDV型与大西洋年代际振荡（AMO）密切相关。AMO激发的Rossby波调制了欧亚大陆的大气环流，导致欧亚大陆出现类似EU的遥相关，并伴有气旋和反气旋交替异常。东亚反气旋异常对GMS有直接影响。这种反气旋异常对GMS降水有双重影响。首先，它导致大湄公河次区域北方上空出现下降异常，并产生偏东异常，阻碍了北方BOB的水汽输送。其次，东亚冬季风加强，减弱了西北太平洋反气旋，有利于南海向GMS南部的水汽输送。因此，大湄公河次区域南部和北方的降水量呈相反的变化。数值试验证实了GMS冬季降水的AMO和IDV之间的因果关系。
In this study, we investigated the interdecadal variability (IDV) of winter precipitation in the Greater Mekong Subregion (GMS) between 1892 and 2016. The results showed that the precipitation IDV was characterized mainly by opposite variations between the southern and northern parts of GMS. This IDV pattern was closely linked to the Atlantic multidecadal oscillation (AMO). Rossby waves excited by the AMO modulated the atmospheric circulation across Eurasia, inducing an EU‐like teleconnection with alternating cyclonic and anticyclonic anomalies across Eurasia. The GMS was directly affected by the anticyclonic anomaly over East Asia. This anticyclonic anomaly had dual effects on the GMS precipitation. Firstly, it caused a descending anomaly over the northern GMS and generated easterly anomalies that impeded the moisture transport from the northern BOB. Secondly, it strengthened the East Asian winter monsoon (EAWM) that weakened the western North Pacific anticyclone (WNPAC) to facilitate moisture transport from South China Sea to the southern GMS. Consequently, the precipitation varied inversely between the southern and northern parts of GMS. Numerical experiments confirmed the causal link between the AMO and IDV of winter precipitation in the GMS.