@proceedings {1048, title = {Phase Coding in Digital SuperDARN Radars to Observe Oblique Scattering}, year = {2026}, month = {03/2026}, publisher = {HamSCI}, address = {Newington, CT}, abstract = {Super Dual Auroral Radar Network (SuperDARN) is a network of HF radars in the mid to high-latitude regions that observe space weather effects on the ionosphere and magnetosphere. These radars typically transmit a single frequency multi-pulse sequence in the 8-22MHz range in a monostatic configuration. Between 2019 and 2020, two radars were reconfigured at certain times to carry out bistatic operations to demonstrate detecting oblique scatter. These operations were limited to intersecting fields-of-view of both radars, and forcing one radar to be receive-only, disrupting regular radar operation. The results of these operations showed a need for a more flexible approach that is not constrained by mode or field-of-view. Since then, some radars in the network have been converted to a Software Defined Radio (SDR) based system. An SDR-based system enables greater configurability in the transmit waveform the radar uses, including the possibility to encode unique radar IDs into the pulse. Operating modes incorporating phase coding are currently in use for their increased range resolution, so phase coding an ID in the transmit pulse would not affect the normal operation of the radar. This work proposes that SuperDARN radar waveforms with phase-coded IDs could be received by low-cost SDRs similar to the PSWS Grape receivers, to study propagation and oblique scattering in the ionosphere.}, author = {Allison Pitzl and Kevin Sterne and Mike Ruohoniemi and Joseph Baker and Bharat Kunduri and Nathaniel Frissell} } @proceedings {970, title = {Southern Hemisphere MSTID response to a Sudden Stratospheric Warming Observed by the Falkland Islands SuperDARN Radar}, year = {2025}, month = {03/2025}, publisher = {HamSCI}, address = {Newark, NJ}, abstract = {

We present a study of Medium Scale Traveling Ionospheric Disturbances (MSTIDs) observed by the Falkland Islands Radar (FIR) in the Southern Hemisphere in response to a sudden stratospheric warming (SSW) event. MSTIDs are quasi-periodic variations in the upper atmospheric (~250 km altitude) plasma with phase speeds of ~100-250 m/s, periods from ~15-60 minutes, and horizontal wavelengths of several hundred kilometers. Daytime MSTIDs are known to be associated with gravity waves (GWs) that originate in the lower and middle atmosphere and propagate upward into the F-region. Neutral wind filtering of these GWs creates a strong dependence of GW-associated MSTIDs on stratospheric and mesospheric zonal wind direction and speed, which is tied to polar vortex strength during fall, winter, and spring months. This dependence manifests as both seasonal and sub-seasonal variability of MSTID amplitudes. Most existing SuperDARN MSTID studies have focused on observations from the Northern Hemisphere. This work uses an automated spectral approach previously used to study Northern Hemisphere winter daytime SuperDARN MSTIDs and applied it to all radars in both hemispheres for all times of day and all seasons for the years 2010-2021. This helped us identify the Southern Hemisphere radars with the highest quality data. One radar for which the retrievals worked particularly well was FIR which illustrates suppressed MSTID activity following the minor SSW beginning on 6 September 2019. This suggests that Southern Hemisphere MSTIDs, like their Northern Hemisphere counterparts, have GW sources in the lower/middle neutral atmosphere and are modulated by the polar vortex jet.\ 

}, author = {James Fox and Nicholas Guerra and Thomas Pisano and Michael Molzen and Nathaniel Frissell and Lynn Harvey and Joseph Klobusicky and Mark Fenner and Joseph Baker and Michael Ruohoniemi} } @proceedings {835, title = {Comparative Analysis of Medium Scale Travelling Ionospheric Disturbances: Grape PSWS vs. SuperDARN}, year = {2024}, month = {03/2024}, publisher = {HamSCI}, address = {Cleveland, OH}, abstract = {

Medium Scale Traveling Ionospheric Disturbances (MSTIDs) are periodic fluctuations in ionospheric electron density associated with atmospheric gravity waves. They are characterized by wavelengths of 50-500 kilometers and periods of 15-60 minutes. This study presents initial findings from a comparative analysis of MSTID observations sourced from two distinct systems: the Super Dual Auroral Radar Network (SuperDARN) and the Grape Personal Space Weather Station (PSWS). The Grape PSWS, developed by the Ham Radio Science Citizen Investigation (HamSCI), is a small ground-based remote sensing device aimed at monitoring space weather parameters, including MSTIDs. It achieves this by monitoring a 10 MHz transmission from WWV, a National Institute of Standards and Technology (NIST) time standard station located near Fort Collins, Colorado, USA. In contrast, SuperDARN comprises a global network of high-frequency radars that offer extensive coverage of ionospheric plasma motion. This comparative investigation focuses on aligning MSTID observations obtained from Grape PSWS data with SuperDARN radar data. By investigating datasets from both platforms, these findings serve as initial results for an ongoing investigation of MSTIDs, laying the groundwork for a comprehensive understanding of their dynamics and impacts on ionospheric variability and space weather.

}, author = {Veronica I. Romanek and Nathaniel A. Frissell and Bharat Kunduri and J. Michael Ruohoniemi and Joseph Baker and William Liles and John Gibbons and Kristina Collins and David Kazdan and Rachel Boedicker} }