Interdecadal Pacific variability modulates recent drying and near-term changes in early-spring precipitation over subtropical East Asia

Subtropical East Asia, among the world's most densely populated regions and a major agricultural region, has experienced pronounced early-spring drying since the 1980s, posing growing risks to water resources and agriculture. However, the relative contributions of external forcing and internal variability to the drying trend, as well as the associated dynamic and thermodynamic processes, remain unclear. The circulation analogues-based dynamic adjustment reveals that atmospheric circulation changes explain approximately 108% of the observed drying trend, which were largely driven by internal variability. These circulation changes are closely linked to a positive-to-negative phase transition of the Interdecadal Pacific Variability (IPV), which can suppress precipitation by weakening the Northwest Pacific anticyclone and inducing anomalous subsidence over subtropical East Asia. The IPV also modulates near-term precipitation projections. Based on the projected IPV inferred from ensemble members that realistically capture the historical IPV, we identify a likely reversal toward wetter conditions in the near future.