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

Abstract

A 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.

Reconstruction of Plasmaspheric Density Distributions by Applying a Tomography Technique to Jason‐1 Plasmaspheric TEC Measurements

“…However, inversion of the ill‐posed problem requires a sophisticated algorithm. Our previous work on ionospheric tomography (Ssessanga et al, ) has inverted the similar equation successfully by adopting a MART algorithm.…”

“…Although the GPS TEC measurements cover the global ionosphere and plasmasphere, only two‐dimensional information (in latitudinal and longitudinal) is directly deduced from such measurements. Vertical distributions of electron density from GPS TEC data have been obtained in ionospheric studies using tomographic techniques (e.g., Das & Shukla, ; Ssessanga et al, , ; Tsai et al, ). The computerized ionospheric tomography enables to investigate vertical structure of the ionosphere.…”

“…However, the pTEC measurements have a minimum in June solstice, indicating the annual anomaly. They also found that the largest annual anomaly occurs in the American sector and the ratio is approximately 1.5 to 2. distributions of electron density from GPS TEC data have been obtained in ionospheric studies using tomographic techniques (e.g., Das & Shukla, 2011;Ssessanga et al, 2015Ssessanga et al, , 2017Tsai et al, 2002). The computerized ionospheric tomography enables to investigate vertical structure of the ionosphere.…”

Multievent Analysis of Oscillatory Motion of Medium‐Scale Traveling Ionospheric Disturbances Observed by a 630‐nm Airglow Imager Over Tromsø

“…MSTIDs are wave-like structures in the ionosphere with horizontal wavelengths of 100-1,000 km and periods of 15 min to 1 hr (Hocke & Schlegel, 1996;Hunsucker, 1982). The phenomenon of MSTIDs has been investigated extensively using a variety of equipment such as ionosondes (Amorim et al, 2011;Ssessanga et al, 2017), satellites beacon (Forbes et al, 2016;Garcia et al, 2016), airglow imagers (Makela et al, 2010;Shiokawa, Ihara, et al, 2003), Global Navigation Satellite Systems (Huang et al, 2018;Otsuka et al, 2013;Saito et al, 1998), and the high frequency (HF) radars (Bristow et al, 1994;Oinats et al, 2016). The 630.0-nm airglow all-sky images particularly stand out because of high spatial resolution (less than 1 km) and ability of revealing the two-dimensional (2-D) structure of MSTIDs.…”

Assimilation of Multiple Data Types to a Regional Ionosphere Model With a 3D‐Var Algorithm (IDA4D)

“…To improve on estimations of climatologic models and still obtain a full 3-D picture of the ionosphere, tomography techniques have extensively been applied (e.g., Hong et al, 2017;Raymund et al, 1990;Saito et al, 2016;Seemala et al, 2014;Ssessanga et al, 2015Ssessanga et al, , 2017Tsai et al, 2002). However, ionosphere tomography techniques have a deficiency of not being able to adequately spread observation information within the grid, specifically over remote areas where measurements are lacking.…”