Antarctic ozone as a precursor to winter central asian precipitation beyond ENSO

Central Asia (CA) experiences large interannual hydroclimate variability that profoundly affects ecosystems, agriculture, and socioeconomic stability. While the El Niño–Southern Oscillation (ENSO) has long been recognized as the leading driver, a significant proportion of observed CA precipitation variability remains unexplained. Here, we reveal that Antarctic ozone variability in October–November serves as a robust and independent precursor to winter CA precipitation (WCAP). Antarctic ozone modulates WCAP through two primary pathways. First, enhanced Antarctic ozone drives a persistent negative phase of the Southern Annular Mode (SAM) that persists into the following winter. The ensuing ozone–SAM coupling shifts two Ferrel cells equatorward and enhances low-level convergence and ascent over CA, thereby increasing WCAP. Second, the negative SAM induces central–eastern South Pacific warming, triggering Rossby wave trains that establish a meridional circulation dipole around CA and strengthen subtropical westerlies, moisture transport, and WCAP. Exposure analyses further indicate that combined ozone–ENSO effects substantially exacerbate precipitation-related socioeconomic risks across CA, adding ~34 billion person-days of population exposure and >34 billion dollar-days of economic exposure by mid-century relative to ENSO alone. Our findings identify Antarctic ozone variability as a critical yet previously underappreciated predictor of CA hydroclimate, revealing subtle interhemispheric connections beyond the traditional ENSO-centric paradigm.