image: The red arrow indicates enhanced convective activity, and the blue arrow indicates enhanced download motion. Blue anti-clockwise arrows signify cyclonic circulation anomalies, and red and yellow clockwise arrows represent anticyclonic anomalies.
Credit: ©Science China Press
A research team led by Qiuxiao Zhu and Dr. Huixin Li from Nanjing University of Information Science and Technology, in collaboration with Dr. Shengping He from the University of Bergen and other collaborators, has uncovered the mechanism by which the Atlantic Multidecadal Oscillation (AMO) modulates interdecadal changes in compound hot drought events (CHDEs) over Northern East Asia.
By analyzing reanalysis datasets during 1940–2022 and conducting Atlantic pacemaker experiments from the CESM1.1 model, the researchers identified two pronounced interdecadal transitions in July CHDEs: a weakening in the mid-1950s and a strengthening in the mid-1990s. These shifts closely align with changes in AMO phases.
When the AMO enters its positive phase, anomalous warming in the North Atlantic triggers Rossby wave trains that propagate across Eurasia. This atmospheric teleconnection causes the northward displacement and intensification of the subtropical westerly jet, strengthens regional high-pressure anomalies, and enhances descending motion over Northern East Asia. These processes suppress rainfall and raise surface temperatures, significantly increasing the intensity and frequency of CHDEs.
The findings provide a new physical perspective for understanding variability in Northern East Asia’s hot droughts and offer a scientific foundation for improving decadal climate prediction and disaster risk management.
See the article:
Zhu Q, Li H, Sun B, He S, Yuan Y, Zeng J, Tan A. 2025. How the AMO influences interdecadal variations of compound hot drought events in Northern East Asia. Science China Earth Sciences, 68(9), 2924–2937, https://doi.org/10.1007/s11430-025-1642-3
Journal
Science China Earth Sciences