++++++++++++++++++ Date: Tue, 25 Sep 2001 18:34:54 -0600 (MDT) From: "Paul Harden, NA5N" To: qrp-canada at neale.gpfn.sk.ca, qrp-l at lehigh.edu Cc: nmqrp at yahoogroups.com, "Prof. Arnaldo Coro Antich" Subject: [107492] STORM/AURORA 25-26 SEPT Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Gang, I know there are new members on QRP-L, QRP-Canada, etc. that have missed some of these solar tutorials over the past couple of years, so this is intended primarily for them. There was a major X-class flare yesterday on the sun. For the duration of this flare, speed of light energy (x-rays and protons) were fired at the earth. This caused poor HF conditions for several hours, but also ionized the E and F layers for good skip propagation -- the situation that exists right now. 10M is wide open during daylight hours right now. The flare also spews out gobs of solar mass that travels outward from the sun at 800-1200 km/sec. When it hits the earth about 2 days later, it triggers a geomagnetic storm. The shockwave from yesterdays flare hit us today, about 30 hours after the flare, or cooking along quite well. This is like a big blast of wind that hits our magnetic field, makes it wiggle to generate huge electrical currents. Those currents also make large noise bursts on 10-15MHz and below. This enhanced noise on the lower bands will persist for a couple of days, wednesday being the worse. This wiggling of our magnetic field, plus the protons from the sun being pumped into the solar regions, also produces aurora, or the northern lights. So there is a good chance of seeing aurora tonight in the northern US. The extent of aurora is always difficult to predict and often surprises observers. So even if you live in the middle US latitudes, it would be worth taking a look northward tonight around 10pm to midnite. Below is portions of todays RSGA report from NOAA, annotated for those interested in the interpretation. SUMMARY: The HIGHER bands are in GREAT shape. The LOWER bands will be experiencing signal loss and enhanced noise. But nothing so severe to stop QRPers from getting on the air. 72, Paul NA5N On Tue, 25 Sep 2001, Space Environment Center wrote: > Joint USAF/NOAA Report of Solar and Geophysical Activity > SDF Number 268 Issued at 2200Z on 25 Sep 2001 > IA. Analysis of Solar Active Regions and Activity from 24/2100Z > to 25/2100Z: Solar activity was high. Region 9628 (S18W14) produced > an M7/1n with associated Type II sweep at 0440 UTC. A Type II sweep are radio emissions starting around 300MHz and sweeping downward into the HF spectrum, caused by the shockwave of the flare punching through the sun's magnetic field lines. Astronomers use this information to calculate the approximate speed of the departing shockwave. To us other earthlings, it tells us a shockwave is on the way. This one was not as energetic as the X-class flare monday, and will probably hit the earth thursday to trigger a minor geomagnetic storm. > In addition, the region also generated an M2/1n with Type II at 1027 UTC Ditto. This flare also produced a shockwave. Since both these flares are near the center of the sun, both shockwaves will contact earth in a couple of days. > IB. Solar Activity Forecast: Solar activity is expected to be > moderate to high. Both Regions 9628 and 9632 retain the potential > for additional M-class activity, and a possible isolated X-class > event. A major flare from these two regions WILL impact earth ... first, HF degradation will occur DURING the flare, and the lower HF frequencies will experience poor conditions two days later when the shockwave arrives. > IIA. Geophysical Activity Summary 24/2100Z to 25/2100Z: > The geomagnetic field was quiet until the end of the interval. A > shock, presumably related to the flare/CME of 24/1038 UTC, passed > ACE at approximately 2003 UTC. > The field is now at active Note that this report, issued at the end of the UTC, is only about 2 hours after the shockwave hit, and insufficient time for the 3-hour K index measurements to be made. Thus, only ACTIVE conditions were measured. Since this report was issued, the K indices of 5 and 6 are being measured across the globe for minor-major storm conditions. > The proton events at greater than 10 and 100 MeV continue. The >10 and >100MeV protons are the energetic proton emissions from the sun. These are striking the earth at near the speed of light, and thus remain as enhanced ionizing radiation. This is good in that it is ionizing the E and F layer for very reflective layers and a high MUF. Good daylight DX propagation exists right now and tomorrow (at least) on 20-10M. BUT ... is IS also wiping out our VE friends, as up north, these protons are also ionizing the D-layer, producing a near HF blackout for them. This will continue another couple of days for them. Ditto for the extreme southern hemisphere, like southern Australia, etc. This phenomenon is called a "Polar Cap Absorption Event." > The Polar Cap Absorption event remains in progress. See? > IIB. Geophysical Activity Forecast: The geomagnetic field is > expected to be at major storm levels during the next 24-36 hours, > due to the effects of a shock/cme related to the X2/2b flare of > 24/1038 UTC. The storm should persist through 27 September. The > current proton events are expected to continue for at least the next > 24 hours. The shockwave hit the earth a few hours ago, triggering a geomagnetic storm. However, as we approach night fall in North America, our part of the earth turns away from the sun, and hence the solar wind, and storm conditions will subside. 40-80M will be extra noisy tonight, but not useless. BUT ... tomorrow at sunrise, North America will rotate again into the high solar wind and the storm will elevate to major storm levels. Thus, the worse conditions will be on the sunlit side of the planet. This is why NOAA is forecasting MAJOR storming tomorrow ... as "the earth turns" back into the solar wind stream. At 0000UTC 26 SEP, the ESTIMATED A-index is already at 80, or major storm conditions. > PCAF in progress As discussed above. Pretty lousy conditions above/below about 50 degrees latitude, and creeping southward/northward. > IV. Penticton 10.7 cm Flux > Observed 25 Sep 275 Don't miss this opportunity to experience a solar flux of 275 on 10M during daylight hours or greyline (as the sun begins to set). The MUF and E/F layer reflectivity maps show excellent reflectivity right now with little path loss. This is the perfect condition for working QRP DX. This condition will persist for several days, and will NOT be heavily bothered by the geomagnetic storm bothering the lower bands. > 90 Day Mean 25 Sep 169 The average solar flux has been 169 for the past 3 months, so to say our current flux of 275 is an abberation is an understatement. Enjoy it!!! > V. Geomagnetic A Indices > Observed Afr/Ap 24 Sep 005/006 > Estimated Afr/Ap 25 Sep 010/012 > Predicted Afr/Ap 26 Sep-28 Sep 080/100-040/040-015/015 ^^^^^^^ ^^^^^^^ ^^^^^^^ WED THURS FRIDAY Predicted: MAJOR storm tomorrow/wednesday, subsiding to minor storming on thursday, and virtually gone by friday. Again, this effects only the lower ham bands, not 20M and above. 30M is in the transition zone, and I would suspect DX signals on 30M would be quite nice tonite and tomorrow nite, but kinda poor tomorrow during the day. 72, Paul NA5N +++++++++++++++++++