@proceedings {949,
	title = {Climatology of Large-Scale Traveling Ionospheric Disturbances Observed with 14 MHz Amateur Radio Using a Novel Automated Detection Technique},
	year = {2025},
	month = {03/2025},
	publisher = {HamSCI},
	address = {Newark, NJ},
	abstract = {<p>We present a multi-year climatology of Large Scale Traveling Ionospheric Disturbance (LSTID) period oscillations observed using 14 MHz amateur (ham) radio data. Traveling ionospheric disturbances (TIDs) are quasi periodic electron density perturbations in the F region ionosphere that affect radio communications and can help with understanding energy transport throughout the coupled magnetosphere-ionosphere-neutral atmosphere system. These are seen, in daytime, as variations in contact ranges in 14 MHz amateur radio communication reports recorded by automated monitoring systems such as the Weak Signal Propagation Reporting Network (WSPRNet), the Reverse Beacon Network (RBN), and PSKReporter. A new deterministic and fully automated method was developed for identifying and quantifying these disturbances. This technique, which filters for TID wave periods between 1 and 5 hours and curve fits a sinusoidal function to the first hop skip-distance edge of observed communication ranges, provides both TID amplitudes and periods. In this study, we present full year climatologies of LSTID events over the continental United States (CONUS) using RBN, WSPRNet, and PSK observations from 2016- 2021. Results are organized as a function wave period, amplitude, and season. We find that LSTIDs increase in winter and decline during the fall and spring, with slight enhancements in the summer and occasional brief declines in LSTID winter activity. This seasonal pattern shows consistency with previous studies and observations of LSTIDs and medium scale TIDs that suggests this behavior may be associated with neutral wind filtering in the middle atmosphere, sudden stratospheric warming (SSW) events, and multi-step vertical coupling (MSVC) processes. MSVC is a process where gravity waves (GWs) from the lower neutral atmosphere propagate upwards, break, and produce new, higher-order GWs in the thermosphere and TIDs in the ionosphere.</p>
},
	author = {Diego Sanchez and Nathaniel Frissell and Mary Lou West and V. Lynn Harvey and Sharon Vadas and Erich Becker and Gareth Perry and William Engelke and Nicholas Callahan and Philip Erickson}
}
@proceedings {628,
	title = {Climatology of Large Scale Traveling Ionospheric Disturbances Observed by HamSCI Amateur Radio with Connections to Geospace and Neutral Atmospheric Sources},
	year = {2022},
	month = {03/2022},
	publisher = {HamSCI},
	address = {Huntsville, AL},
	abstract = {<p>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{\textquoteright}s Modern-Era Retrospective Analysis for Research and Applications Version 2 (MERRA-2).</p>
},
	author = {Diego S. Sanchez and Nathaniel A. Frissell and Gareth W. Perry and V. Lynn Harvey and William D. Engelke and Anthea Coster and Philip J. Erickson and J. Michael Ruohoniemi and Joseph B. H. Baker}
}
