DPS-4D EI764 064 / 64.630750, -147.042904

Propagation for Snipers Net 3920 KHz 0200 UTC (Net Roster)

Receiver Audio Location - 64.6 / 147.4


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B. NOAA Solar Radiation Activity Observation and Forecast

Solar radiation, as observed by NOAA GOES-13 over the past 24 hours, was
above S-scale storm level thresholds.

Solar Radiation Storm Forecast for Sep 12-Sep 14 2017

              Sep 12  Sep 13  Sep 14
S1 or greater   99%     80%     60%

Rationale: The greater than 10 MeV proton flux is expected to continue
at S2 (Moderate) levels on day one (12 Sep), with S1-S2 (Minor-Moderate)
levels likely on day two (13 Sep) and S1 (Minor) levels on day three (14
Sep) as the radiation storm slowly decreases intensity. The greater than
100 MeV flux levels are expected to remain enhanced, but continue to
decrease on day one as well, with levels possibly remaining above the 1
pfu level into day two.

# Global Ionospheric Radio Observatory

# GIRO Tabulated Ionospheric Characteristics, Version 1.0 Revision B
# Generated by DIDBGetValues on 2017-09-12T04:32:45.575Z
# Location: GEO 64.66N 212.93E, URSI-Code EI764 EIELSON
# Instrument: Ionosonde, Model: DPS-4D
# Query for measurement intervals of time:
# 2017-09-12T02:00:00.000Z - 2017-09-12T02:30:00.000Z

 # foF2 [MHz] - F2 layer critical frequency

#Time                     CS   foF2 QD



Latest 24 Hour Ionogram Movies for Eielson AFB



Propagation Failure

Ionograms reveal no return signal reflections and recorded transmission were only of local ground wave stations


Hypothesized Conclusion

Failure of propagation due to a 10MeV Proton event producing Polar Cap Absorption manifesting as major D-Layer signal attenuation for central Alaska and other areas north of 60 degrees north latitude as shown on the below chart. 

D-Layer attenuation associated with reports by NOAA of Radio Blackout Activity

Radio blackouts reaching the R3 levels were observed over the past 24
hours. The largest was at Sep 10 2017 1606 UTC

Radio Blackout Forecast for Sep 11-Sep 13 2017

              Sep 11        Sep 12        Sep 13
R1-R2           80%           10%            1%
R3 or greater   50%            1%            1%

Rationale: The potential for R1-R3 (Minor-Strong) radio blackouts exists
on day one (Sep 11) from Region 2673. Probabilities are expected to drop
rapidly as the region moves further around the far-side of the Sun on
days two and three (Sep 12-13).



10MeV Proton event in progress, 12 09 2017 0020UT flux =    727 pfu

Area in RED defined as Polar Cap Absorption

Being an artifact of the above noted Proton event.


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