Wave Signals From Rapidly Intensifying Typhoons Mark Vortex Adjustment Rather Than Robust Ionospheric Coupling

Abstract Rapidly intensifying typhoons can generate atmospheric waves, but nearby neutral‐atmosphere and ionospheric anomalies need not form a robust cross‐layer coupling chain. We examine 75 western North Pacific rapid‐intensification events during 2018–2023. Across 65 paired events, an ERA5 upper‐tropospheric omega–wind covariance‐amplitude proxy increases by 0.177 from 24 hr before onset to onset (Wilcoxon ). Co‐located vertical‐motion, wind, and temperature perturbations are consistent with transient vortex adjustment, although ERA5 cannot isolate freely propagating waves. The derived metrics add little rapid‐intensification discrimination in life‐cycle, hourly, and matched non‐RI comparisons (oriented AUC = 0.503–0.540). AIRS daily maxima are indistinguishable from same‐day regional maxima, and CODE maps neither resolve propagating ionospheric fronts nor yield robust source–response relations after background controls. The available signals therefore mark resolved‐scale vortex adjustment more clearly than robust ionospheric coupling. This limit applies to the observing products and does not rule out coupling detectable with denser regional measurements.