@article {802, title = {Validating Ionospheric Models Against Technologically Relevant MetricsAbstractPlain Language SummaryKey Points}, journal = {Space Weather}, volume = {21}, year = {2023}, month = {Jan-12-2023}, abstract = {

New, open access tools have been developed to validate ionospheric models in terms of technologically relevant metrics. These are ionospheric errors on GPS 3D position, HF ham radio communications, and peak F-region density. To demonstrate these tools, we have used output from Sami is Another Model of the Ionosphere (SAMI3) driven by high-latitude electric potentials derived from Active Magnetosphere and Planetary Electrodynamics Response Experiment, covering the first available month of operation using Iridium-NEXT data (March 2019). Output of this model is now available for visualization and download via\ https://sami3.jhuapl.edu. The GPS test indicates SAMI3 reduces ionospheric errors on 3D position solutions from 1.9\ m with no model to 1.6\ m on average (maximum error: 14.2\ m without correction, 13.9\ m with correction). SAMI3 predicts 55.5\% of reported amateur radio links between 2{\textendash}30\ MHz and 500{\textendash}2,000\ km. Autoscaled and then machine learning {\textquotedblleft}cleaned{\textquotedblright} Digisonde NmF2 data indicate a 1.0\ {\texttimes}\ 1011\ el. m3\ median positive bias in SAMI3 (equivalent to a 27\% overestimation). The positive NmF2 bias is largest during the daytime, which may explain the relatively good performance in predicting HF links then. The underlying data sources and software used here are publicly available, so that interested groups may apply these tests to other models and time intervals.

}, issn = {1542-7390}, doi = {10.1029/2023SW003590}, url = {https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2023SW003590https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2023SW003590https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2023SW003590}, author = {Chartier, A. T. and Steele, J. and Sugar, G. and Themens, D. R. and Vines, S. K. and Huba, J. D.} } @conference {277, title = {Modeling Amateur Radio Soundings of the Ionospheric Response to the 2017 Great American Eclipse}, booktitle = {Fall AGU}, year = {2018}, month = {12/2018}, publisher = {American Geophysical Union Meeting}, organization = {American Geophysical Union Meeting}, address = {Washington, DC}, abstract = {

On 21 August 2017, a total solar eclipse traversed the continental United States and caused large-scale changes in ionospheric densities. These were detected as changes in medium- and high-frequency radio propagation by the Solar Eclipse QSO Party citizen science experiment organized by the Ham Radio Science Citizen Investigation (hamsci.org). This is the first eclipse-ionospheric study to make use of measurements from a citizen-operated, global-scale HF propagation network and develop tools for comparison to a physics-based model ionosphere. Eclipse effects were observed {\textpm}0.3 hr on 1.8 MHz, {\textpm}0.75 hr on 3.5 and 7 MHz, and {\textpm}1 hr on 14 MHz and are consistent with eclipse-induced ionospheric densities. Observations were simulated using the PHaRLAP raytracing toolkit in conjunction with the eclipsed SAMI3 ionospheric model. Model results suggest 1.8, 3.5, and 7 MHz refracted at h>=125 km altitude with elevation angles θ>=22{\textdegree}, while 14 MHz signals refracted at h \< 125 km with elevation angles θ \< 10{\textdegree}.

}, keywords = {Amateur Radio, Citizen Science, Ham Radio, HF propagation, ionosphere, solar eclipse}, url = {https://agu.confex.com/agu/fm18/meetingapp.cgi/Paper/418915}, author = {Frissell, N. A. and Katz, J. D. and Gunning, S. W. and Vega, J. S. and Gerrard, A. J. and Earle, G. D. and Moses, M. L. and West, M. L. and Huba, J. D. and Erickson, P. J. and Miller, E. S. and Gerzoff, R. B. and Liles, W. and Silver, H. W.} }