@conference {586,
	title = {Amateur Radio Communications as a Novel Sensor of Large Scale Traveling Ionospheric Disturbances (Invited)},
	booktitle = {American Geophysical Union Fall Meeting},
	year = {2021},
	month = {12},
	publisher = {American Geophysical Union},
	organization = {American Geophysical Union},
	address = {New Orleans, LA},
	abstract = {<p>Amateur (ham) radio high frequency (HF) communications are routinely observed by automated receiving systems on a quasi-global scale. As these signals are modulated by the ionosphere, it is possible to use these observations to remotely sense ionospheric dynamics and the coupled geospace environment. In this presentation, we demonstrate the use of these data to observe Large Scale Traveling Ionospheric Disturbances (LSTIDs), which are quasi-periodic variations in F region electron density with horizontal wavelengths \&gt; 1000 km and periods between 30 to 180 min. On 3 November 2017, LSTID signatures were detected simultaneously over the continental United States in observations made by global HF amateur radio observing networks and the Blackstone (BKS) SuperDARN radar. The amateur radio LSTIDs were observed on the 7 and 14 MHz amateur radio bands as changes in average propagation path length with time, while the LSTIDs were observed by SuperDARN as oscillations of average scatter range. LSTID period lengthened from T ~ 1.5 hr at 12 UT to T ~ 2.25 hr by 21 UT. The amateur radio and BKS SuperDARN radar observations corresponded with Global Navigation Satellite System differential Total Electron Content (GNSS dTEC) measurements. dTEC was used to estimate LSTID parameters: horizontal wavelength 1136 km, phase velocity 1280 km/hr, period 53 min, and propagation azimuth 167{\textdegree}. The LSTID signatures were observed throughout the day following ~400 to 800 nT surges in the Auroral Electrojet (AE) index. As a contrast, 16 May 2017 was identified as a period with significant amateur radio coverage but no LSTID signatures in spite of similar geomagnetic conditions and AE activity as the 3 November event. We hypothesize that atmospheric gravity wave (AGW) sources triggered by auroral electrojet intensifications and associated Joule heating are the source of the LSTIDs, and discuss possible reasons why LSTIDs were observed in November but not May.</p>
},
	url = {https://agu.confex.com/agu/fm21/meetingapp.cgi/Paper/822746},
	author = {Frissell, Nathaniel A. and Sanchez, Diego F. and Perry, Gareth W. and Kaeppler, Steven R. and Joshi, Dev Raj and Engelke, William and Thomas, Evan G. and Coster, Anthea J. and Erickson, Philip J. and Ruohoniemi, J. Michael and Baker, Joseph B. H.}
}
@proceedings {575,
	title = {Climatology of Traveling Ionospheric Disturbances Observed by HamSCI Amateur Radio with Connections to Geospace and Neutral Atmospheric Sources},
	year = {2021},
	month = {09/2021},
	publisher = {ARRL-TAPR},
	address = {Virtual},
	url = {https://youtu.be/MHkz7jNynOg?t=23773},
	author = {Sanchez, Diego F. and Frissell, Nathaniel A. and Perry, Gareth W. and Engelke, William D. and Coster, Anthea J. and Erickson, Philip J. and Ruohoniemi, J. Michael and Baker, Joseph B. H. and Harvey, Lynn and Luetzelschwab, R. Carl}
}
@proceedings {559,
	title = {HamSCI: Ham Radio Science Citizen Investigation},
	year = {2021},
	month = {09/2021},
	publisher = {International Space Weather Action Team (ISWAT)},
	address = {Virtual},
	author = {Frissell, Nathaniel A. and Sanchez, Diego and Perry, Gareth W. and Kaeppler, Stephen R. and Joshi, Dev Raj and Engelke, William D. and Thomas, Evan G. and Coster, Anthea J. and Erickson, Philip J. and Ruohoniemi, J. Michael and Baker, Joseph B. H. and Gerzoff, Robert}
}
@proceedings {578,
	title = {HF Doppler Observations of Traveling Ionospheric Disturbances in the WWV Signal Received with a Network of Low-Cost HamSCI Personal Space Weather Stations},
	year = {2021},
	month = {09/2021},
	publisher = {ARRL-TAPR},
	address = {Virtual},
	url = {https://youtu.be/kVY3E3e--_I?t=3495},
	author = {Romanek, Veronica I. and Frissell, Nathaniel A. and Joshi, Dev Raj and Liles, William and Trop, Claire and Collins, Kristina and Perry, Gareth W.}
}
@conference {580,
	title = {HF Doppler Observations of Traveling Ionospheric Disturbances in the WWV Signal Received with a Network of Low-Cost HamSCI Personal Space Weather Stations},
	booktitle = {American Geophysical Union Fall Meeting},
	year = {2021},
	month = {12},
	publisher = {American Geophysical Union},
	organization = {American Geophysical Union},
	address = {New Orleans, LA},
	abstract = {<p>Traveling Ionospheric Disturbances (TIDs) are quasi-periodic variations in ionospheric electron density that are often associated with atmospheric gravity waves. TIDs cause amplitude and frequency variations in high frequency (HF, 3-30 MHz) refracted radio waves. We present observations of TIDs made with a network of Ham Radio Science Citizen Investigation (HamSCI) Low-Cost Personal Space Weather Stations (PSWS) with nodes located in Pennsylvania, New Jersey, and Ohio. The TIDs were detected in the Doppler shifted carrier of the received signal from the WWV frequency and time standard station near Fort Collins, CO. Using a lagged cross correlation analysis, we demonstrate a method for determining TID wavelength, direction, and period using the collected WWV HF Doppler shifted data.</p>
},
	url = {https://agu.confex.com/agu/fm21/meetingapp.cgi/Paper/888443},
	author = {Romanek, Veronica I. and Frissell, Nathaniel A. and Joshi, Dev Raj and Liles, William and Trop, Clair and Collins, Kristina and Perry, Gareth W.}
}
@proceedings {555,
	title = {Sources of Large Scale Traveling Ionospheric Disturbances Observed using HamSCI Amateur Radio, SuperDARN, and GNSS TEC},
	year = {2021},
	month = {05/2021},
	publisher = {SANSA},
	address = {Virtual},
	url = {https://www.sansa.org.za/events-outreach/superdarn-workshop-2021/},
	author = {Frissell, Nathaniel A. and Sanchez, Diego F. and Perry, Gareth W. and Joshi, Dev Raj and Engelke, William D. and Thomas, Evan G. and Coster, Anthea J. and Erickson, Philip J. and Ruohoniemi, J. Michael and Baker, Joseph B. H.}
}
@proceedings {574,
	title = {Sources of Large Scale Traveling Ionospheric Disturbances Observed using HamSCI Amateur Radio, SuperDARN, and GNSS TEC},
	year = {2021},
	month = {09/2021},
	publisher = {ARRL-TAPR},
	address = {Virtual},
	url = {https://youtu.be/MHkz7jNynOg?t=22608},
	author = {Frissell, Nathaniel A. and Sanchez, Diego F. and Perry, Gareth W. and Kaeppler, Stephen R. and Joshi, Dev Raj and Engelke, William D. and Thomas, Evan G. and Coster, Anthea J. and Erickson, Philip J. and Ruohoniemi, J. Michael and Baker, Joseph B. H.}
}
