<div dir="ltr">Graham,<div><br></div><div>Thanks for posting those links. I don't utilize TEC data because it doesn't relate to my study, but time series TEC data will show scintillation on GNSS signals which would be useful in this case. I've only ever had these anomalies where geomagnetic storming affected my local region of the ionosphere which includes when aurora was observed in my state. Once I find some scintillation data for that day, I'll try to do some correlation.</div><div><br></div><div>Thanks again.</div><div><br></div><div>Jonathan</div><div>KC3EEY</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, Sep 26, 2023 at 4:08 PM Graham c <<a href="mailto:colonelkrypton@gmail.com">colonelkrypton@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">Jonathan,<div><br></div><div>You may already be well aware but on the off chance you are not, there are a number of Canadian locations along the north shores of lake Erie and Ontario as part of the Canadian Active Control System ( ACS ) <a href="https://webapp.csrs-scrs.nrcan-rncan.gc.ca/geod/data-donnees/cacs-scca.php" target="_blank">https://webapp.csrs-scrs.nrcan-rncan.gc.ca/geod/data-donnees/cacs-scca.php</a> which provide data that is used for ionospheric purposes <a href="https://meteospatiale.gc.ca/data-donnee/ionosphere/index-en.php" target="_blank">https://meteospatiale.gc.ca/data-donnee/ionosphere/index-en.php</a> </div><div><br></div><div>Historical TEC data can be either plotted ( jpg or png ) or as an HTML table from here: <a href="https://meteospatiale.gc.ca/data-donnee/ionosphere/tec-arch-en.php" target="_blank">https://meteospatiale.gc.ca/data-donnee/ionosphere/tec-arch-en.php</a></div><div><br></div><div>I would guess from your work that you are already aware and I am just preaching to choir but there may be others on the list who are not aware and may find this data interesting.</div><div><br></div><div>cheers, Graham ve3gtc</div><div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, Sep 25, 2023 at 7:38 AM Jonathan <<a href="mailto:emuman100@gmail.com" target="_blank">emuman100@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="auto">Come to think of it, does anyone have access to GNSS TEC plots from GNSS receivers in Pennsylvania or surrounding states on both days?</div><div dir="auto"><br></div><div dir="auto">Jonathan</div><div dir="auto">KC3EEY </div><div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, Sep 25, 2023 at 6:55 AM Jonathan <<a href="mailto:emuman100@gmail.com" target="_blank">emuman100@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">A really cool effect was observed on the VLF system during the strong geomagnetic storming of 9/19 and 9/20. I believe that the scintillation of the GNSS signal during that period produced a lot of error in the timing solution of the GNSS receiver which resulted in a sawtooth characteristic in the absolute phase measurement in NAA, which that measurement is referenced to GNSS timing. This geomagnetic storming event caused visible aurora, characteristic of low latitudes (red emissions) across Pennsylvania. <div dir="auto"><br></div><div dir="auto">Here is the plot of the NAA diurnal on 9/19/23 showing the effect of the scintillation in the absolute phase measurement as well as two SIDs caused by solar flares:<div dir="auto"><div><img src="cid:18acbf3e3201de287341" style="width: 628px; max-width: 100%;"></div><div dir="auto"><br></div><div dir="auto">And on 9/20/23, showing more SIDs and the sawtooth effect past the initial onset of the geomagnetic storm:</div><div dir="auto"><div><img src="cid:18acbf5bc1682289b352" style="width: 616px; max-width: 100%;"></div><br></div><div dir="auto">Not only that, the nighttime portion of the diurnal (00:00-10:00) show the D layer being affected by the CME, showing different absorption variation than the night before. There are some SIDs as well, so these plots are indicating quite a bit of activity and a really nice observation.</div></div></div><div dir="auto"><div dir="auto"><div dir="auto"><br></div><div dir="auto">Jonathan</div><div dir="auto">KC3EEY </div> </div></div>
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