A 3‐D empirical model of <i>F</i> region Medium‐Scale Traveling Ionospheric Disturbance bands using incoherent scatter radar and all‐sky imaging at Arecibo

Abstract

Perhaps the most persistent and prominent of the midlatitude nighttime F region phenomena observed with all‐sky imagers is the Medium‐Scale Traveling Ionospheric Disturbances (MSTID) that occur when the geomagnetic activity is low. We introduce a simple empirical 3‐D model of these bands, which was developed on the basis of an extension of results given by Seker et al. (2008). Seker et al. (2008) reported observational results on the 3‐D geometry of MSTID structures found using combined incoherent scatter radar (ISR) and all‐sky imager observations over the Arecibo Observatory in Puerto Rico. To confirm and further investigate these findings, a simple empirical 3‐D model of nighttime MSTID bands is constructed. We show ISR and all‐sky imager results derived from the model, compare them with the actual observations, and highlight the important findings. This model is intended to replicate both the azimuth‐scanning ISR and the all‐sky imager results and is especially useful in explaining how these complex structures appear in azimuth‐scanning ISR results. In addition, confidence in the empirical model allows us to know what to expect from the theory (of MSTID) and to assess how well geomagnetically quiet, nighttime, midlatitude, F region electrodynamics models succeed. Furthermore, the technique described in the paper is not limited to F region or midlatitudes only; it could be applied to any other phenomenon which can be observed by both radar and imager.