Tree‐Ring Evidence for Solar Radiation Modulation of Sea Surface Temperature–Western Pacific Subtropical High Relationship

The western Pacific subtropical high (WPSH) profoundly influences climate changes and disaster frequencies in the densely populated East Asia. Yet, the mechanisms, drivers, and future changes of WPSH remain unclear. Here the longest annual resolution reconstruction of the summer WPSH intensity is presented using tree‐ring width and stable isotope from the southeastern China. WPSH displays intensified strength and variability since the 1950s, alongside increased extreme events. Tropical sea surface temperature (SST) from the Pacific, Atlantic and Indian Oceans influences WPSH intensity with significant spatial and temporal heterogeneity over the past 390 years. The eastern Pacific tropical SST has the strongest impact, though their relationship is unstable on multi‐decadal scales. Strong solar radiation influences the positive relationship between the eastern Pacific tropical SST and WPSH by modulating their mean intensity or variability. Despite the Coupled Model Intercomparison Project Phase 6 climate models projecting enhanced WPSH under greenhouse warming scenarios, time series prediction indicates that WPSH will weaken before enhancing in the next 50 years, modulated by solar radiation fluctuations. These findings underscore the dual necessity of preparing for natural disasters induced by extremely strong WPSH events and addressing potential climate anomalies arising from extremely weak WPSH conditions in the future.