Statistical study of relationship between medium-scale traveling ionospheric disturbance and sporadic E layer activities in summer night over Japan

Abstract

We investigate the relationship between medium-scale traveling ionospheric disturbance (MSTID) and sporadic E ( E s ) layer activities in summer nights by analyzing total electron content (TEC) data obtained from a global positioning system (GPS) network in Japan and ionosonde data obtained at Kokubunji, Japan during May–August in 2001–2005. MSTID activity is defined as δ I / I ¯ , where δ I is standard deviation of the TEC perturbations over Kokubunji within 1 h, and I ¯ is the background TEC. By analyzing nighttime-averaged (19-02 LT) values of MSTID activity and E s layer parameters, we find that the MSTID activity is closely correlated with f 0 E s and f 0 E s - f b E s . This result suggests that MSTID and the spatial structures of E s layer could be generated by an electro-dynamical coupling process between the E s layer and F region through polarization electric fields. Furthermore, we suggest that the appearance of the E s layer in the summer hemisphere could play an important role in generating MSTIDs in both hemispheres.