A moon shadow passed through the region of eastern and southern China and ends near sunset (∼09:30 UT) under the solar minimum condition on 21 June 2020. It is an opportunity to study the ionospheric behaviors influenced by the solar eclipse at low latitudes. Wang et al. (2021) analyzed the behaviors of the sporadic-E (E s ) layer during the solar eclipse on 21 June 2020. The continuously upward and downward movement of the E s layer reveals a prominent transport process occurring in the vertical direction of the ionosphere during the obscuration.It is known that the transport effect dominants the F region during an eclipse (Dear et al., 2020;Rishbeth, 1970;Tsai & Liu, 1999). Dang et al. (2020) simulated the thermospheric and ionospheric responses to the annular solar eclipse on 21 June 2020 using a coupled thermosphere-ionosphere-electrodynamics model. They suggested that the solar eclipse could cause the total electron content (TEC) enhancement in the equatorial ionospheric anomaly (EIA) area for nearly 4.5 hr under the influence of the transequatorial plasma transport. Using the ground-and space-based observations, Zhang et al. ( 2020) and Huang et al. (2020) showed that the ionospheric responses to the annular solar eclipse, such as the disturbances of TEC, electron density and temperature, and maximum plasma density of F 2 layer (N m F 2 ), are much complicated at low latitudes. They suggested that the disturbed electric field, neutral winds, thermal conduction, interhemispheric photoelectron transport process, are mainly responsible for these complicated behaviors. Aa et al. ( 2021) also observed these similar ionospheric behaviors and suggested that the perturbations in the field-aligned thermal conduction during the solar eclipse lead to the possible interconnections between the eclipse and the conjugate ionospheres. Sun et al. (2021) analyzed the TEC data from the ground-based Global Navigation Satellite System (GNSS) receivers over east and south Asia as well as the ionospheric F 2 layer critical frequency (f o F 2 ) and its height (h m F 2 ) recorded by the ionosonde at Puer (22.7°N, 101.05°E, 72% obscuration) on 21 June 2020. Their results showed that the eclipse-induced TEC perturbations behave as a large-scale terminator wave propagating northwestward after sunset. The previous studies comprehensively examined the effects of the eclipse on the ionosphere. However, the effect of the vertical plasma drifts on the F-layer induced by this solar eclipse was not clearly identified yet.

The enhancement in the ionospheric electron density (Ne) can be greater in the nighttime than that in the daytime, which is one of the special phenomena during local summer in both the Northern and Southern Hemispheres at the geomagnetic midlatitudes (