  This study investigates the spatial and temporal characteristics of L1
amplitude scintillation-causing ionospheric irregularities over the Eastern
Arabian Peninsula during the ascending phase of solar cycle 25 (years
2020--2023). The temporal occurrences of weak and strong scintillation were
separated by sunset, with weak scintillation observed predominantly pre-sunset
during the winter solstice and strong scintillation observed mainly post-sunset
during the autumnal equinox. Strong scintillation was much more pronounced in
2023 compared to the other three years, indicating a strong influence of solar
activity. Spatially, weak-scintillation-causing irregularities exhibited a wide
distribution in azimuth and elevation, while strong-scintillation-causing
irregularities were concentrated southwards. The combined analysis of S4 and
rate of total electron content index (ROTI) suggested that small-scale
ionospheric irregularities were present in both pre- and post-sunset periods,
while large-scale irregularities were only seen during the post-sunset period.
Furthermore, the presence of southward traveling ionospheric disturbances
(TIDs) during the 2023 autumnal equinox was confirmed with the total electron
content anomaly ($\Delta\text{TEC}$), while the Ionospheric Bubble Index (IBI)
provided by the Swarm mission was unable to confirm the presence of equatorial
plasma bubbles during the same period. Observations from the
FORMOSAT-7/COSMIC-2 mission indicated that strong-scintillation-causing
irregularities were more prevalent under the F2-layer peak, while the
weak-scintillation-causing irregularities were mostly observed at the E-layer,
F2-layer, and above the F2-layer.
