Abstract:
The occurrence of late night spread F in the low and equatorial latitude regions during solar
minimum is not properly understood. Radar observations have revealed occurrence of postmidnight
echoes at low and equatorial latitudes during solar minimum periods. This work discusses the coordinated
airglow, VHF radar, and ionosonde observations of nighttime electrified medium‐scale traveling ionospheric
disturbances (EMSTIDs) made from the low and equatorial latitude Indian region. Two nights of
observations are discussed in detail in which EMSTIDs are seen to coexist with spread F in ionograms and
VHF backscatter. These observations reveal that the EMSTIDs propagate to latitudes very close to dip
equator at times and they can be responsible for a reasonable portion of the postmidnight radar echoes and
spread F events observed at low and equatorial latitudes during low solar activity period.
