The First Observation of Additional Ionospheric Layers Over Arecibo Using an Incoherent Scatter Radar

Abstract

AbstractWe present an analysis of additional ionospheric F‐region layers, the F3 layers at Arecibo (18.3°N, 32°N geomagnetic latitude). The F3 layer is often observed in low geomagnetic latitudes observed above the F2 layer. This is the first time that the F3 layer is reported at Arecibo, which has a dip angle of 43.6°. Three F3 layer events were captured by the Arecibo incoherent scatter radar at around 400 km in the period of 03:00–07:00 LT, 04:00–06:00 LT, and 02:00–06:30 LT on 30 November, 1 December, and 2 December 2016, respectively. The formation of the observed layers is largely due to the change of the height gradient of the vertical ion drift, which accumulates the electrons at around 400 km. This generation mechanism is further verified by the simulation. The altitudinal variation of the vertical ion drift is mainly due to the effect of the westward electric field.