Citation:Mao, Y.-C. and C. Y. Lin, 2021: VHF scintillations and plasma drifts observed in southern Taiwan during the declining phase of solar cycle 24. Terr. Atmos. Ocean. Sci., 32, 553-560, doi: 10.3319/TAO.2021.09.16.02
Multi-temporal variations of VHF scintillations investigated at EIA latitude
Strong/weak scintillations have different local-time dependences
Dayside plasma drifts are prominently westward and nightside drifts are eastward
4 indices, occurrences and east-west drifts are investigated with respect to local time, season, and solar activity. The results show that strong scintillations (S4 > 0.5) appear frequently at early nighttime at equinoxes during the high solar activity year of 2015, while weak scintillations (S4: 0.2 - 0.5) occur often at early daytime and more frequently at early nighttime in summer without obvious correlation with solar activity levels. The peak drift of ~50 - 60 m s-1 is observed eastward at night and westward during the day. Stronger scintillations and higher drift velocities are observed in spring and fall.