@proceedings {873, title = {Reexamining the Characteristics of Flare-Driven Doppler Flash using multipoint HF Observations}, year = {2024}, month = {03/2024}, publisher = {HamSCI}, address = {Cleveland, OH}, abstract = {

Sudden enhancement in the ionospheric electron density following a solar flare causes disruption in the transionospheric high frequency (HF: 3-30 MHz) communications, commonly referred to as Shortwave Fadeout (SWF). This disruption is also recorded as a sudden enhancement in Doppler frequency in the received HF signal, referred to as Doppler Flash. This phenomenon was recorded and reported by the SuperDARN HF radar network. Previous investigations have suggested that among various phases of flare-driven SWFs observed by HF radars Doppler Flash is the first to observe, and there are no significant trends in Doppler Flash with location, operating frequency, or flare intensity. Recent development showed that Doppler observations from the distributed HamSCI Personal Space Weather Station (PSWS) can provide insight into the physics behind changes in phase path length of the trans ionospheric radio signals. Unlike SuperDARN, HamSCI PSWS can record the full phase of the Doppler Flash, provide an edge to revisit the characterization study and compare with existing dataset. In this study, we demonstrate how HamSCI observations can be used to infer flare-driven changes in ionospheric properties. We found: (1) HamSCI PSWS has higher dynamic range than SuperDARN during flare making it less susceptible to SWF, thus it can record the full Doppler Flash; (2) data from HamSCI PSWS shows a strong function trend with flare strength, operating frequency, and location on the Earth; and (3) HF rays traveling longer distances experienced statistically higher Doppler. We understand that, while instantaneous Doppler realized by the HF signal is proportional to the rate of change in solar irradiance, the total Doppler realized is proportional to the total flare-deposited energy in the ionosphere.

}, author = {Shibaji Chakraborty and Kristina V. Collins and Nathaniel A. Frissell and J. Michael Ruohoniemi and Joseph B. H. Baker} } @proceedings {876, title = {Reworking the MUSIC Algorithm to Mitigate MSTID Direction Estimation Bias Associated with SuperDARN Radar Field-of-View Geometry}, year = {2024}, month = {03/2024}, publisher = {HamSCI}, address = {Cleveland, OH}, abstract = {

Medium Scale Traveling Ionospheric Disturbances (MSTIDs) are variations in the F region ionospheric electron density. MSTIDs can be associated with atmospheric gravity waves (AGWs) and provide critical information for understanding the ionosphere, which is an electrically charged region of the atmosphere. Previous SuperDARN studies of MSTIDs have used the Multiple Signal Classification (MUSIC) algorithm to determine the size, speed, and direction of these disturbances in the ionosphere. Upon analyzing MSTID MUSIC results from ten North American SuperDARN radars over a period of twelve winter seasons (2010-2022), we found a bias in the SuperDARN MSTID MUSIC direction estimation algorithm that preferentially reports waves as traveling along the boresight direction of the radars. We demonstrate that this bias is caused by the radar Field-of-View geometry and report on the progress algorithm development for removing this bias.

}, author = {Michael Molzen and Thomas Pisano and Nicholas Guerra and Juan Serna and Nathaniel A. Frissell} } @proceedings {752, title = {A Review of "Climatology of Medium Scale Traveling Ionospheric Disturbances Observed by the Midlatitude Blackstone SuperDARN Radar"}, year = {2023}, month = {03/2023}, publisher = {HamSCI}, address = {Scranton, PA}, abstract = {

This poster is a review of Frissell et al. (2014) by undergraduate students for the purpose of learning about SuperDARN and MSTIDs as part of a
research project to study the differences between MSTIDs observed in the Northern and Southern Hemispheres.

Frissell, N. A., Baker, J. B. H., Ruohoniemi, J. M., Gerrard, A. J., Miller, E. S., Marini, J. P., West, M. L., and Bristow, W. A. (2014), Climatology of medium-scale traveling ionospheric disturbances observed by the midlatitude Blackstone SuperDARN radar, J. Geophys. Res. Space Physics, 119, 7679{\textendash} 7697, doi:10.1002/2014JA019870.

}, author = {Nicholas Guerra and Michael Molzen and James Fox and Juan Serna and Nathaniel A. Frissell} }