A statistical study on the F2 layer vertical variation during nighttime medium‐scale traveling ionospheric disturbances

Abstract

AbstractA statistical study on the relationship between the perturbation component (ΔTEC (total electron content)) and the F2 layer peak height (hmF2) during nighttime medium‐scale traveling ionospheric disturbances is presented. The results are obtained by using a time‐dependent computerized ionospheric tomography (CIT) technique. This was realized by using slant total electron content observations from a dense Global Positioning System receiver network over Japan (with more than 1000 receivers), together with a multiplicative algebraic reconstruction technique. Reconstructions from CIT were validated by using ionosonde and occultation measurements. A total of 36 different time snapshots of the ionosphere when medium‐scale traveling ionospheric disturbances (MSTIDs) were eminent were analyzed. These were obtained from a data set covering years from 2011 to 2014. The reconstructed surface wavefronts of ΔTEC and hmF2 structure were found to be aligned along the northwest‐southeast direction. These results confirm that nighttime MSTIDs are driven by electrodynamic forces related to Perkins instability which explains the northwest‐southeast wavefront alignment based on the F region electrodynamics. Furthermore, from the statistical analysis hmF2 varied quasiperiodically in altitude with dominant peak‐to‐peak amplitudes between 10 and 40 km. In addition, ΔTEC and hmF2 were 60% anticorrelated.