Decadal‐Scale Increase in the Risk of Compound Hot‐Drought Events Over the Yangtze River Valley: The Indirect Forcing of the Atlantic Multidecadal Oscillation

In recent years, compound hot‐drought events (CHDEs) have occurred with increasing frequency in the Yangtze River Valley in China. These extreme events have a severe effect on societal and ecological systems, as well as the economy. To identify the primary drivers of this decadal‐scale intensification of CHDEs, we present empirical and modeling evidence that demonstrates that the Atlantic Multidecadal Oscillation (AMO) exerts a dual effect on the decadal‐scale increase in CHDEs in the Yangtze River Valley. The AMO‐related high pressure over the northeastern flank of the South Asian High (SAH) directly contributes to its eastward extent. In addition, the AMO has facilitated the recent rapid warming of the Arabian Sea through the amplification of a positive wind‐evaporation‐sea surface temperature feedback. Warming in the northern Arabian Sea has further modified regional precipitation across the northern Arabian Sea and northwestern India. Subsequently, the pronounced interdecadal increase in summer precipitation has triggered anomalous diabatic heating, and thus strengthened the upper‐level West Asian High center on the circum‐global teleconnection system. It has also strengthened the downstream East Asian High center that extends the upper SAH. This study highlights the need to consider the dual effects of the AMO when investigating CHDEs.