Long‐Term Climatology of Low‐Latitude Ionospheric Scintillation: Solar‐Geomagnetic Modulation and a Possible Gravity‐Wave Pathway in Summer

Abstract

Based on 12 years of observational data from Hainan (2013–2024), we systematically investigated the long‐term modulation of low‐latitude ionospheric scintillation by solar activity, with a focus on the physical mechanisms underlying summer scintillation. Using multi‐source observations and wavelet transform time‐frequency analysis, we find that scintillation occurrence and intensity are positively correlated with solar activity, whereas geomagnetic activity generally suppresses scintillation. During solar‐minimum summers, weak scintillation persists despite suppressed EPB activity and is predominantly associated with frequency spread‐F. Case studies reveal quasi‐1‐hr periodicities, together with atmospheric temperature perturbations and ionospheric TEC disturbances, suggesting a possible contribution from upward‐propagating atmospheric gravity waves. These waves may perturb the background ionosphere and provide seed disturbances that are subsequently amplified into small‐to medium‐scale irregularities. Our results suggest that atmospheric gravity‐wave forcing may provide an important pathway for summer nighttime irregularities when classical EPB‐related electrodynamic forcing is weak, advancing our understanding of low‐latitude scintillation climatology and its underlying physics.