Equatorial F‐region neutral winds from nightglow OI 630.0 nm Doppler shifts

Abstract

A Fabry‐Perot interferometer has been used to determine equatorial thermospheric wind velocities from measurements of the doppler shifts in the twilight and nightglow 630.0 nm emission line observed from Kwajelein Atoll (9° 24′ N., 167° 29′ E.) during August and September 1977. Shortly after sunset, the F‐region neutral winds typically are directed roughly eastward at velocities ranging from 50 to 120 m/sec. The velocity grows moderately in magnitude for several hours and then turns somewhat southward, sometimes decreasing in the late night (∼03 h local time) to small values (<50 m/sec). These measurements are compatible with recent inferences from measurements of satellite orbit changes but disagree in some respects with pressure‐gradient model predictions and with the winds inferred from OGO‐4 135.6 nm and 630.0 nm airglow intensity measurements.