5:15 PM - 7:15 PM
[PEM12-P27] Observation of Es using the range measurement function of the HF Doppler observation system
Keywords:HF Doppler, Ranging, Sporadic E layer (Es), High resolution observation
We have added an FMCW range measurement function to the HF Doppler observation system of the University of Electro-Communications, and ionospheric reflection heights between Chofu and Chiba (50km) have been continuously observed at frequencies of 5.006MHz and 8.006MHz. The ionospheric sporadic E layer (Es) of foEs>5MHz is observable with this system with height and time resolutions of 1km and 50ms respectively. Sequential Es generated by zonal wind shear becomes active in the East Asia from May to August, and daily variation of atmospheric tides can be traced. We reported on the altitude change of the sequential Es in the summer of 2024 at the previous conference. Es activity is observed to occur irregularly even during the inactive period from September to April. We will report on the altitude variation of Es throughout the year.
Prior to the disappearance of the sequential Es, which descends to around 100 km due to atmospheric tides, mobile Es is observed with a characteristic signal form in both Doppler and range measurements. We will analyze one year's mobile Es observed simultaneously with Doppler and ranging, and will report a comparison of the occurrence altitude of the mobile Es with the sequential Es.
Prior to the disappearance of the sequential Es, which descends to around 100 km due to atmospheric tides, mobile Es is observed with a characteristic signal form in both Doppler and range measurements. We will analyze one year's mobile Es observed simultaneously with Doppler and ranging, and will report a comparison of the occurrence altitude of the mobile Es with the sequential Es.