TY - Generic T1 - Exploring Ionospheric Variability Through Doppler Residuals: A Study Utilizing the HamSCI Grape V1 Receiver T2 - HamSCI Workshop 2024 Y1 - 2024 A1 - Sabastian Fernandes A1 - Gareth W. Perry A1 - Tiago Trigo A1 - John Gibbons AB -

This study leverages the capabilities of the Grape V1 low-IF receiver to analyze both long and short-term patterns of high frequency (HF; 3-30 MHz) skywave signals. The HF spectrum, often used for global long-range communications, also spans the frequencies used for remote sensing of the near-Earth plasma environment. The Grape receiver (callsign K2MFF) used in this study is located at the New Jersey Institute of Technology (NJIT) in Newark, NJ. At a rate of 1 Hz, it samples its link to the WWV broadcasting station transmitting at 10 MHz from Fort Collins, CO. The Doppler shift in this radio link, caused by its interactions with the ionosphere, is measured to study fluctuations in the ionosphere's electron density. This methodology provides insight into the effects of geomagnetic activity on the terrestrial ionosphere, caused by complex processes in the coupled Sun-Earth plasma environment. Our results show that the signal received during the daytime is less prone to Doppler shift than when received during the nighttime. This night-day contrast is consistent across most 24-hour cycles, barring dates of antenna maintenance or severe geomagnetic storms. We also found a strong correlation between daytime measurements and Cauchy statistics, and between nighttime measurements and a mixture of exponential power / lognormal statistics, wherein day and night at the geographic midpoint between WWV and NJIT are considered. The identification of these differing statistical regimes per time of day has led us to characterize long-term trends in the dataset by the medians of day and night Doppler measurements, independently. Additionally, the receiver's sensitivity and versatility was affirmed through case-studies of atypical Doppler traces captured in the data stream, by identifying characteristic markers of solar flares and solar eclipses.

JF - HamSCI Workshop 2024 PB - HamSCI CY - Cleveland, OH ER - 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 - Signatures of Space Weather in the NJIT V1 Grape Low-IF Receiver T2 - HamSCI Workshop 2024 Y1 - 2024 A1 - Tiago Trigo A1 - Gareth W. Perry A1 - Sebastian Fernandes A1 - John Gibbons A1 - Nathaniel A. Frissell AB -

The V1 Grape Low Intermediate Frequency (Low-IF; 10 MHz) Receiver is part of a low-cost Personal Space Weather Station (PSWS) developed by the Ham Radio Science Citizen Investigation (HamSCI) Collective. One of the existing deployed Grapes is located at the New Jersey Institute of Technology (NJIT). The Grape measures the WWV 10 MHz signal originating from Fort Collins, Colorado. Variations in WWV's signal intensity and frequency, received by the Grape can be used to investigate  strong space weather events and their effects on the Earth's ionosphere. The Grape data is separated into two parameters, Doppler Shift (Hz) which is a change in frequency introduced by the variability of the ionosphere along the WWV to NJIT link, and Relative Power (dB) which can be used as a proxy for the received signal's intensity.  In this presentation, we will explore the possibility of using the Relative Power parameter for studying ionospheric scintillation due to space weather events.  We will present several examples of data collected on days with known space weather events to assess the Grape's ability to detect the event. We will also discuss our analysis techniques, including our strategies to mitigate the local noise environment at NJIT, and future work.

JF - HamSCI Workshop 2024 ER - TY - Generic T1 - Climatology of Large Scale Traveling Ionospheric Disturbances Observed with Amateur Radio Networks T2 - HamSCI Workshop 2023 Y1 - 2023 A1 - Diego Sanchez A1 - Mary Lou West A1 - Bob Gerzoff A1 - Gareth W. Perry A1 - Nathaniel A. Frissell A1 - William D. Engelke A1 - Philip J. Erickson AB -

A new climatology of Large Scale Traveling Ionospheric Disturbances (LSTIDs) has been observed from ham radio data in 2017. LSTIDs are quasiperiodic electron density perturbations of the F region ionosphere. LSTIDs have periods of 30 min to over 180 min, wavelengths of over 1000 km, and velocities of over 1400 km/hr. In this paper, we show a climatology of observed LSTID events using data from the Reverse Beacon Network (RBN), Weak Signal Propagation Network (WSPRNet), and PSKReporter amateur radio networks. This climatology was performed twice and was cross examined between two members of the research team. Results show that most of the observed LSTIDs occurred during the winter months with a decline towards the summer, with the exception of a spike in June. This paper provides additional insight into the seasonal trends of LSTIDs and provides additional knowledge that will help in the pursuit of what is causing this phenomenon.

JF - HamSCI Workshop 2023 PB - HamSCI CY - Scranton, PA ER - TY - Generic T1 - A Few Science Questions that HamSCI Can Help Address During the 2023 and 2024 Eclipses T2 - HamSCI Workshop 2023 Y1 - 2023 A1 - Gareth W. Perry A1 - Nathaniel A. Frissell A1 - Joseph D. Huba AB -

Solar eclipses are an exciting celestial event which can be used to study the terrestrial atmosphere and ionosphere systems. Locally, during a total solar eclipse, totality may only last a few minutes—and the times scales on which solar illumination decreases and then increases is much shorter that what is normally observed during sunrise and sunset. Additionally, on a larger, continental scale, the moon’s umbra moves at supersonic velocities, tracing out the path of totality. These properties serve to act as an impulse in energy on the atmosphere and ionosphere, generating a wide variety of yet to be specified (or identified) responses in those systems. 

As an example of some compelling response effects, the fast depletion-replenishment of the bottomside ionosphere (the portion of the ionosphere that is below the F-region peak) often appears asymmetric—an observation that is not well understood. Therefore, one science question which can be addressed is: will the different geometries of the 2023 and 2024 eclipses as well as the fact that they are an annular and total eclipse, respectively, have a significant effect on the asymmetry of the bottomside evolution during the eclipse? Furthermore, efforts to model and replicate the observed effects of eclipses have significantly improved in recent years; however, observations of the atmosphere and ionosphere are still required to constrain, validate, and ultimately improve our theoretical understanding of these systems. Another eclipse science question which can be addressed is: how well will these models perform for the 2023 and 2024 eclipse and how can we quantify the response of the ionosphere during these events? 

Over the past few years, HamSCI has emerged at the forefront of passive remote sensing techniques in solar-terrestrial physics. This is evidenced by HamSCI’s work using with HF timing signals and HF QSOs, show that both can be used to monitor the bottomside ionosphere on both regional and continental scales. The SEQP during the 2017 total solar eclipse was a resounding success, delivering high-impact and influential science results. Building upon that success, this technique may very well be a gamechanger for identifying and characterizing eclipse generated effects and phenomena during the upcoming 2023 and 2024 eclipses. The purpose of this presentation is to detail a few outstanding eclipse related science questions, and propose how HamSCI can lead the way in addressing them.

JF - HamSCI Workshop 2023 PB - HamSCI CY - Scranton, PA 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 - JOUR T1 - Amateur Radio: An Integral Tool for Atmospheric, Ionospheric, and Space Physics Research and Operations JF - White Paper Submitted to the National Academy of Sciences Decadal Survey for Solar and Space Physics (Heliophysics) 2024-2033 Y1 - 2022 A1 - Nathaniel A. Frissell A1 - Laura Brandt A1 - Stephen A. Cerwin A1 - Kristina V. Collins A1 - David Kazdan A1 - John Gibbons A1 - William D. Engelke A1 - Rachel M. Frissell A1 - Robert B. Gerzoff A1 - Stephen R. Kaeppler A1 - Vincent Ledvina A1 - William Liles A1 - Michael Lombardi A1 - Elizabeth MacDonald A1 - Francesca Di Mare A1 - Ethan S. Miller A1 - Gareth W. Perry A1 - Jonathan D. Rizzo A1 - Diego F. Sanchez A1 - H. Lawrence Serra A1 - H. Ward Silver A1 - David R. Themens A1 - Mary Lou West 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 - TY - JOUR T1 - Fostering Collaborations with the Amateur Radio Community JF - White Paper Submitted to the National Academy of Sciences Decadal Survey for Solar and Space Physics (Heliophysics) 2024-2033 Y1 - 2022 A1 - Nathaniel A. Frissell A1 - Laura Brandt A1 - Stephen A. Cerwin A1 - Kristina V. Collins A1 - Timothy J. Duffy A1 - David Kazdan A1 - John Gibbons A1 - William D. Engelke A1 - Rachel M. Frissell A1 - Robert B. Gerzoff A1 - Stephen R. Kaeppler A1 - Vincent Ledvina A1 - William Liles A1 - Elizabeth MacDonald A1 - Gareth W. Perry A1 - Jonathan D. Rizzo A1 - Diego F. Sanchez A1 - H. Lawrence Serra A1 - H. Ward Silver A1 - Tamitha Mulligan Skov A1 - Mary Lou West ER - TY - Generic T1 - Potential Science Opportunities for HamSCI in Antarctica T2 - HamSCI Workshop 2022 Y1 - 2022 A1 - Gareth W. Perry A1 - Nathaniel A. Frissell AB -

The maturation and proliferation of passive radio receivers based on software defined radio principles and architecture herald a new era of radio remote sensing in solar-terrestrial physics. Antarctica is a region of interest for deploying HF radio receivers for many reasons. The significant offset of the geographic and magnetic poles allows one to study multiple terrestrial magnetosphere-ionosphere-thermosphere regions of interest, e.g., the polar, auroral, and sub-auroral zones, using ground-based instruments. Additionally, the significant snow and ice coverage in Antarctica is a strong absorber of HF radio waves. This severely mitigates intracontinental multi-hop propagation modes, which may be advantageous for geolocating geophysical features detected by HF radio techniques, thereby improving remote sensing performance. In this poster presentation, we will analyze a case of a QSO between two operators, captured by a receiver located at McMurdo Station in Antarctica. We will discuss the signal characteristics of each transmission and pay particularly close attention to how variations in the CW transmissions may be linked to geophysical processes occurring in the region at the time. The overarching goal of this presentation is to incite discussion on how existing and future passive HF receiving systems in Antarctica can leveraged to advance not only the art of radio but solar-terrestrial physics in Antarctica.

JF - HamSCI Workshop 2022 PB - HamSCI CY - Huntsville, AL ER - TY - Generic T1 - Properties and Drivers of Plasma Irregularities in the High-Latitude Ionosphere Computed using Novel Incoherent Scatter Radar Techniques T2 - HamSCI Workshop 2022 Y1 - 2022 A1 - Lindsay V. Goodwin A1 - Gareth W. Perry AB -

To provide new insights into the relationship between geomagnetic conditions and plasma irregularity scale-sizes, high-latitude irregularity spectra are computed using novel Incoherent Scatter Radar (ISR) techniques. This new technique leverages: 1) the ability of phased array Advanced Modular ISR (AMISR) technology to collect volumetric measurements of plasma density, 2) the slow F-region cross-field plasma diffusion at scales greater than 10 km, and 3) the high dip angle of geomagnetic field lines at high-latitudes. The resulting irregularity spectra are of a higher spatiotemporal resolution than has been previously possible with ISRs. Spatial structures as small as 20 km are resolved in less than two minutes (depending on the radar mode). In this work, we focus on Resolute Bay ISR observations operating in high-beam modes, such as the imaginglp mode. In addition to having an unprecedented view of the size and occurrence of irregularities as they traverse the polar cap, we find that near magnetic local noon the spectral power shifts to scales greater than 50 km, and from 15 to 5 magnetic local time the spectral power shifts to structures less than 50 km. This either reflects the role of polar cap convection in breaking down structures as they travel from the dayside ionosphere to the nightside, or the role of photoionization "smoothing" the dayside ionosphere. Additionally, during periods of enhanced geomagnetic conditions, such as periods with low AL indices, the spectral power shifts to structures 50 km and larger. This presentation will discuss these findings, as well as show seasonal variations.

JF - HamSCI Workshop 2022 PB - HamSCI CY - Huntsville, AL ER - TY - CONF T1 - HF Doppler Observations of Traveling Ionospheric Disturbances in a WWV Signal Received with a Network of Low-Cost HamSCI Personal Space Weather Stations T2 - Annual (Summer) Eastern Conference Y1 - 2021 A1 - Veronica I. Romanek A1 - Nathaniel A. Frissell A1 - Dev Raj Joshi A1 - William Liles A1 - Claire C. Trop A1 - Kristina V. Collins A1 - Gareth W. Perry AB -

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. One way to detect TIDs is through the use of a Grape Personal Space Weather Station (PSWS). The Grape PSWS successfully detected TIDs in the Doppler shifted carrier of the received signal from the 10 MHz WWV frequency and time standard station in Fort Collins, CO. This paper will present an explanation of how the Grape PSWS was used to collect data, and how scientist can use this data to further investigate the ionosphere.

JF - Annual (Summer) Eastern Conference PB - Society of Amateur Radio Astronomers (SARA) CY - Virtual UR - https://rasdr.org/store/books/books/journals/proceedings-of-annual-conference ER - TY - Generic T1 - K2MFF: Nearly a Century of Advancing the Radio Art at NJIT T2 - HamSCI Workshop 2021 Y1 - 2021 A1 - Gareth W. Perry A1 - F. Chu A1 - Peter Teklinski AB -

The New Jersey Institute of Technology Amateur Radio Club (NJITARC), K2MFF, has been an active part of the NJIT community for nearly a century.  K2MFF has been a diligent community member, volunteering in such large-scale events as the New York City Marathon for over 30 years.  Not only that, K2MFF, has been a fertile ground for developing young technical talent and advances in the radio art.  Indeed, K2MFF has been a supporter and contributor to the HamSCI effort since its inception.  In this presentation, we will offer a brief history of K2MFF, and discuss the current status and activities of the club.  We will also offer some prognosis of the club’s future directions.

JF - HamSCI Workshop 2021 PB - HamSCI CY - Scranton, PA (Virtual) UR - https://hamsci2021-uscranton.ipostersessions.com/?s=6A-73-A8-1F-B3-F9-DE-00-42-92-9A-F7-6B-59-C4-ED ER - TY - CONF T1 - Observing Large Scale Traveling Ionospheric Disturbances using HamSCI Amateur Radio: Climatology with Connections to Geospace and Neutral Atmospheric Sources T2 - NSF CEDAR (Coupling, Energetics, and Dynamics of Atmospheric Regions) Y1 - 2021 A1 - Diego F. Sanchez A1 - Nathaniel A. Frissell A1 - Gareth W. Perry A1 - William D. Engelke A1 - Anthea Coster A1 - Philip J. Erickson A1 - J. Michael Ruohoniemi A1 - Joseph B. H. Baker AB -

Large Scale Traveling lonospheric Disturbances (TIDs) are propagating variations in ionospheric electron densities that affect radio communications. LSTIDs create concavities in the ionospheric electron density profile that move horizontally with the LSTID and cause skip-distance focusing effects for high frequency (HF, 3-30 MHz) radio signals propagating through the ionosphere. This phenomena manifests as quasi-periodic variations in contact ranges in HF amateur radio communications recorded by automated monitoring systems such as RBN and WSPRNet. In this study, members of the Ham Radio Science Citizen Investigation (HamSCI) present a climatology of LSTID activity as well as 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, season, and geomagnetic activity level. Connections to neutral atmospheric sources are also explored.

JF - NSF CEDAR (Coupling, Energetics, and Dynamics of Atmospheric Regions) PB - CEDAR CY - Virtual ER - TY - Generic T1 - Observing Traveling Ionospheric Disturbances using HamSCI Amateur Radio: Validation and Climatology T2 - HamSCI Workshop 2021 Y1 - 2021 A1 - Diego F. Sanchez A1 - Nathaniel A. Frissell A1 - Gareth W. Perry A1 - William D. Engelke A1 - Anthea Coster A1 - Philip J. Erickson A1 - J. Michael Ruohoniemi A1 - Joseph B. H. Baker AB -

Traveling lonospheric Disturbances (TIDs) are propagating variations in ionospheric electron densities that affect radio communications and can help with understanding energy transport throughout the coupled magnetosphere-ionosphere-neutral atmosphere system. Large scale TIDs (LSTIDs) have periods T\ \approx30-180\ min, horizontal phase velocities v_H\approx‍100-‍250 m/s, and horizontal wavelengths \lambda_H>1000 km and are believed to be generated either by geomagnetic activity or lower atmospheric sources. TIDs create concavities in the ionospheric electron density profile that move horizontally with the TID and cause skip-distance focusing effects for high frequency (HF, 3-30 MHz) radio signals propagating through the ionosphere. 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). First in this study, members of the Ham Radio Science Citizen Investigation (HamSCI) present a case study showing consistency in LSTID signatures in RBN and WSPRNet are also present in Super Dual Auroral Radar Network (SuperDARN), Global Navigation Satellite System (GNSS), and ionosonde measurements. Then, we present a climatology of LSTID activity as well as  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.

JF - HamSCI Workshop 2021 PB - HamSCI CY - Scranton, PA (Virtual) ER - TY - CONF T1 - Sources of Large Scale Traveling Ionospheric Disturbances Observed using HamSCI Amateur Radio, SuperDARN, and GNSS TEC T2 - NSF CEDAR (Coupling, Energetics, and Dynamics of Atmospheric Regions) Y1 - 2021 A1 - Nathaniel A. Frissell A1 - Diego F. Sanchez A1 - Gareth W. Perry A1 - Dev Joshi A1 - William D. Engelke A1 - Evan G. Thomas A1 - Anthea Coster A1 - Philip J. Erickson A1 - J. Michael Ruohoniemi A1 - Joseph B. H. Baker AB -

Large Scale Traveling Ionospheric Disturbances (LSTIDs) are quasi-periodic variations in F region electron density with horizontal wavelengths > 1000 km and periods between 30 to 180 min. On 3 November 2017, LSTID signatures were detected in simultaneously over the continental United States in observations made by global High Frequency (HF) amateur (ham) 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°. 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 that seasonal neutral atmospheric conditions may play a role in preventing AGW propagation in May but not in November.

JF - NSF CEDAR (Coupling, Energetics, and Dynamics of Atmospheric Regions) PB - CEDAR CY - Virtual ER - TY - CONF T1 - Large Scale Traveling Ionospheric Disturbances Observed using HamSCI Amateur Radio, SuperDARN, and GNSS TEC T2 - American Geophysical Union Fall Meeting Y1 - 2019 A1 - Nathaniel A. Frissell A1 - Diego F. Sanchez A1 - Evan Markowitz A1 - Gareth W. Perry A1 - William D. Engelke A1 - Anthea Coster A1 - Philip J. Erickson A1 - J. Michael Ruohoniemi A1 - Joseph B. H. Baker AB -

Large Scale Traveling Ionospheric Disturbances (LSTIDs) are quasi-periodic variations in F region electron density with horizontal wavelengths > 1000 km and periods between 30 to 180 min. On 3 November 2017, LSTID signatures were detected in observations made by Reverse Beacon Network (RBN) and the Weak Signal Propagation Reporting Network (WSPRNet) for the first time. The RBN and WSPRNet are two large-scale High Frequency (HF, 3-30 MHz) amateur (ham) radio observing networks that provide data to the Ham Radio Science Citizen Investigation (HamSCI). The LSTIDs were observed on the 7 and 14 MHz amateur radio bands, and are detected by observing changes in average propagation path length with time. LSTID period lengthened from T ~ 1.5 hr at 12 UT to T ~ 2.25 hr by 21 UT. Simultaneous LSTID signatures were present in ham radio observations over the continental United States, the Atlantic Ocean, and Europe. LSTIDs observed with amateur radio were consistent with LSTIDs observed by the Blackstone SuperDARN HF radar and in differential GNSS Total Electron Content (TEC) measurements. GNSS TEC maps were used to estimate LSTID parameters: horizontal wavelength 1100 km, phase velocity 950 km/hr, period 70 min, and propagation azimuth 135°. The LSTID signatures were observed throughout the day following ~800 nT surges in the Auroral Electrojet (AE) index at 00 and 12 UT. We will discuss potential generation hypotheses for the observed LSTIDs, including atmospheric gravity wave (AGW) sources triggered by auroral electrojet intensifications and associated Joule heating.

JF - American Geophysical Union Fall Meeting PB - American Geophysical Union CY - San Francisco, CA UR - https://agu.confex.com/agu/fm19/meetingapp.cgi/Paper/581488 ER - TY - CONF T1 - Sounding the Ionosphere with Signals of Opportunity in the High-Frequency (HF) Band T2 - HamSCI Workshop 2019 Y1 - 2019 A1 - Ethan S. Miller A1 - Gary S. Bust A1 - Gareth W. Perry A1 - Stephen R. Kaeppler A1 - Juha Vierinen A1 - Nathaniel A. Frissell A1 - A. A. Knuth A1 - Philip J. Erickson A1 - Romina Nikoukar A1 - Alexander T. Chartier A1 - P. Santos A1 - C. Brum A1 - J. T. Fentzke A1 - T. R. Hanley A1 - Andrew J. Gerrard AB -

The explosion of commercial off-the-shelf (COTS) education- and consumer-grade hardware supporting software-defined radio (SDR) over the past two decades has revolutionized many aspects of radio science, bringing the cost and calibration of traditionally complex receiver hardware within the grasp of even advanced amateur experimenters. Transmission has now become the limiter of access in many cases, particularly through spectrum management and licensing considerations. Fortunately, several classes of signals endemic to the HF band lend themselves to processing for ionospheric characteristics: time and frequency standard broadcasters, surface-wave oceanographic radars, amateur radio transmissions, and ionospheric sounders.

This presentation is a tour of these signals of opportunity and techniques for collecting and processing them into ionospheric characteristics, with emphasis on distributed receivers collecting on a small number (four or fewer) of coherent channels. Receiving techniques will be discussed for near-vertical (“quasi-vertical”) incidence skywave (NVIS or QVI), long-distance oblique soundings, and transionospheric sounding. Soundings will be demonstrated from space-based, ground-based, and maritime platforms.

Binary, Doppler, delay, cone angle of arrival, and polarization observations will be exploited, depending on the signal type and capability of the collector. Each of these techniques conveys different, but not always “orthogonal,” information about the ionospheric skywave channel. The information content of each datum will be discussed with respect to the implications for inverting the local or regional ionosphere from the observations. More importantly than inverting the full ionosphere, some of these techniques are sensitive indicators of ionospheric irregularities, structures, and instabilities, that might otherwise be difficult to study due to limited geographic coverage with larger, more exquisite instrumentation.

JF - HamSCI Workshop 2019 PB - HamSCI CY - Cleveland, OH ER -