TY - Generic T1 - Possible Drivers of Large Scale Traveling Ionospheric Disturbances by Analysis of Aggregated Ham Radio Contacts T2 - HamSCI Workshop 2024 Y1 - 2024 A1 - Diego Sanchez A1 - Mary Lou West A1 - Nathaniel A. Frissell A1 - Gareth W. Perry A1 - William D. Engelke A1 - Robert B. Gerzoff A1 - Philip J. Erickson A1 - J. Michael Ruohoniemi A1 - Joseph B. H. Baker A1 - V. Lynn Harvey AB -

Large Scale Traveling Ionospheric Disturbances (LSTIDs) are quasiperiodic electron density perturbations of the F region ionosphere that have periods of 30 min to over 180 min, wavelengths of over 1000 km, and velocities of 150 to 1000 m/s. These are seen as long slow oscillations in the bottom side of the ionosphere in data from ham radio contacts at 20 meters wavelength on roughly a third of the days in a year. They might be triggered by electromagnetic forces from above, and/or by mechanical pressures from below. The explosion of the Tonga volcano on January 15, 2022 revealed that such a LSTID could be triggered by a violent updraft from the Earth’s surface into the stratosphere and then detected in the ionosphere over the United States nine hours later. We consider other possible drivers such as the auroral electrojet, the polar vortex, thunderstorms, zonal wind speeds, gravity wave variances, and their time derivatives in 2017.

JF - HamSCI Workshop 2024 PB - HamSCI CY - Cleveland, OH ER - TY - Generic T1 - Medium Scale Traveling Ionospheric Disturbances and their Connection to the Lower and Middle Atmosphere T2 - HamSCI Workshop 2023 Y1 - 2023 A1 - Nathaniel A. Frissell A1 - Francis Tholley A1 - V. Lynn Harvey A1 - Sophie R. Phillips A1 - Katrina Bossert A1 - Sevag Derghazarian A1 - Larisa Goncharenko A1 - Richard Collins A1 - Mary Lou West A1 - Diego F. Sanchez A1 - Gareth W. Perry A1 - Robert B. Gerzoff A1 - Philip J. Erickson A1 - William D. Engelke A1 - Nicholas Callahan A1 - Lucas Underbakke A1 - Travis Atkison A1 - J. Michael Ruohoniemi A1 - Joseph B. H. Baker JF - HamSCI Workshop 2023 PB - HamSCI CY - Scranton, PA ER - TY - Generic T1 - Climatology of Large Scale Traveling Ionospheric Disturbances Observed by HamSCI Amateur Radio with Connections to Geospace and Neutral Atmospheric Sources T2 - HamSCI Workshop 2022 Y1 - 2022 A1 - Diego S. Sanchez A1 - Nathaniel A. Frissell A1 - Gareth W. Perry A1 - V. Lynn Harvey A1 - William D. Engelke A1 - Anthea Coster A1 - Philip J. Erickson A1 - J. Michael Ruohoniemi A1 - Joseph B. H. Baker AB -

Traveling Ionospheric Disturbances (TIDs) are propagating variations of F-region ionospheric electron densities that can affect the range and quality of High Frequency (HF, 3-30 MHz) radio communications. TIDs create concavities in the ionospheric electron density profile that move horizontally with the TID and cause skip-distance focusing effects for high frequency radio signals propagating through the ionosphere. TIDs are of great interest scientifically because they are often associated with neutral Atmospheric Gravity Waves (AGWs) and can be used to advance understanding of atmosphere-ionosphere coupling. Large scale TIDs (LSTIDs) have periods of 30-180 min, horizontal phase velocities of 100 - 250 m/s, and horizontal wavelengths of over 1000 km and are believed to be generated either by geomagnetic activity or lower atmospheric sources. The signature of this phenomena is manifest as quasi-periodic variations in contact ranges in HF amateur radio communication reports recorded by automated monitoring systems such as the Weak Signal Propagation Reporting Network (WSPRNet) and the Reverse Beacon Network (RBN). Current amateur radio observations are only able to detect LSTIDs. In this study, we present a climatology of LSTID activity using RBN and WSPRNet observations on the 1.8, 3.5, 7, 14, 21, and 28 MHz amateur radio bands from 2017. Results will be organized as a function observation frequency, longitudinal sector (North America and Europe), season, and geomagnetic activity level. Connections to geospace are explored via SYM-H and Auroral Electrojet indexes, while neutral atmospheric sources are explored using NASA’s Modern-Era Retrospective Analysis for Research and Applications Version 2 (MERRA-2).

JF - HamSCI Workshop 2022 PB - HamSCI CY - Huntsville, AL ER -