The influence of the Atlantic multidecadal oscillation on the interdecadal variability of winter precipitation in the Greater Mekong Subregion.

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. [ABSTRACT FROM AUTHOR]