@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 {972,
	title = {Investigating January 2016 Traveling Ionospheric Disturbance Causes with SuperDARN},
	year = {2025},
	month = {03/2025},
	publisher = {HamSCI},
	address = {Newark, NJ},
	abstract = {<p>Medium-Scale Traveling Ionospheric Disturbances (MSTIDs) are quasi-periodic variations of F-region ionospheric densities that are most often associated with atmospheric gravity waves (GWs) generated in the lower neutral atmosphere. The ionospheric variations caused by MSTIDs can focus and defocus HF radio signals, propagating through the ionosphere, thereby causing changes in the range at which these radio signals are refracted back to Earth. Using this principle, high frequency radars such as those in the Super Dual Auroral Radar Network (SuperDARN) can be used to observe MSTIDs. The SuperDARN MSTID Multiple Signal Classification (MUSIC) Algorithm can be used to determine the period, wavelength, speed, and direction of propagation of the observed MSTIDs. We present SuperDARN observations over the North American continent for the period of 11-16 January 2016 as shown in Vadas et. Al. 2024. \&nbsp;This period is known to be important in terms of the polar vortex generating GWs that seed MSTID activity through multi-step vertical coupling processes. A period of low MSTID activity is observed from 11-13 January followed by a period of elevated MSTID activity from 14-16 January, which is observed across multiple radar fields of view. For this period of interest, an Investigation of MUSIC{\textquoteright}s radar-by-radar reports of observed MSTID parameters including direction of propagation, speed, and period and their comparison to polar vortex activity level observation is also presented.\&nbsp;</p>
},
	author = {Michael Molzen and Nathaniel Frissell and Sharon Vadas and Lynn Harvey}
}
