Observations of neutral winds and electric fields using backscatter from field-aligned irregularities

Abstract

Ionospheric F2-layer disturbances not related to geomagnetic activity (Q disturbances) were analyzed using all available N_mF2 observations over 26 Northern Hemisphere high-to-lower latitude ionosonde stations. Both positive and negative Q disturbances were revealed, their amplitude being comparable to moderate F2-layer storm effects. The occurrence of Q disturbances exhibits a systematic dependence on solar activity, season, and local time. Spatial variation pattern is different for positive and negative Q disturbances with the amplitude of the former increasing with latitude while the amplitude of the latter being practically latitudinal-independent. Longitudinal variations of the amplitude for both types of disturbances look like a planetary wave with minimal deviations in the American sector and maximal deviations in the European sector. Large longitudinal gradients in N_mF2 can appear on the front of such waves.