The K7RA Solar Update
This has been quite a week for dramatic solar activity. The average daily sunspot number was up nearly 26 points to 69.4, while the average daily solar flux rose nearly 17 points to 121.9 for the period March 1-7. Sunspot numbers for March 1-7 were 24, 24, 52, 70, 105, 109 and 102, with a mean of 69.4. The 10.7 cm flux was 103.4, 108.2, 116.4, 120.1, 131.6, 138.1 and 135.7, with a mean of 121.9. The estimated planetary A indices were 14, 10, 8, 12, 8, 8 and 44, with a mean of 14.9. The estimated mid-latitude A indices were 12, 10, 8, 10, 11, 10 and 33, with a mean of 13.4.
The latest forecast has solar flux at 140 on March 9, 135 on March 10-13, 130 on March 14, 125 on March 15-17, then 120, 115, 115, 110, 110 on March 18-22, then back down to 105 on March 23-25. The predicted planetary A index for March 9-13 is 27, 12, 10, 10 and 12, then 5 on March 14-16, then 12, 15, 10, and 8 on March 17-20, and 5 on March 21-27.
A series of coronal mass ejections emerged from a very large sunspot group (1429), and a large one produced a shockwave that hit the ACE spacecraft at 1045 UTC Thursday. I had been out earlier looking for aurora as well as a dark place to watch it, as the shock was expected to hit at 0630 UTC, but that was plus or minus seven hours caveat on the forecast. By the time it hit, I was back at home. I was using real time geomagnetic data to look for a rise in activity, which can be accessed by hitting the Submit Query button here. For some reason, the shockwave was more noticeable at mid-latitude magnetometers than those at the far north.
Early today (Friday morning), another CME hit Earth, and geomagnetic activity is still high, with the planetary K index reaching 7. This is a good place to see changes in geomagnetic conditions recorded every three hours.
On Thursday, NPR featured an excellent interview with Joe Kunches of NOAA’s Space Weather Prediction Center in Boulder. Listen as he gives a clear explanation of what a CME is, and talks about effects to Earth and satellites above. Note also that the Boulder facility is also on Facebook.
Find more on solar activity here.
Among all of this activity, I’ve not heard anything from VHF operators about auroral communications. But we did get this interesting note from Jim Parkinson, W9JEF, of Tontitown, Arkansas: “I operate low band (160, 80 and 40 meters), tying the feeders of my 80 meter turnstile together as a flat top with a vertical run of 48 feet. I run 400-500 W. On March 7 at 0748, I heard K8QKY on 40 meters CW, with considerable flutter on his 599 signal with some fading signals, and sometimes a sort of echo, which may have indicated simultaneous long path propagation. I gave him a call, and Steve gave me a 599 (from Ann Arbor, Michigan); he reported a similar sound on my sig. Then at 0801, NN6T in Kingman, Arizona gave me a call, and I observed the same effect on Glen’s signal, but he said mine sounded ‘FB’ (presumably he had his 2 el beam headed in my direction, so maybe aurora instead of long path) -- 599 in both ways, again with fading signals. At 0837, I heard ZL1BVB, but not as strong as the two times I worked him (days earlier).”
Note that around the time Jim worked NN6T and K8QKY, the planetary K index was 6, and the planetary A index for that day was 44.
We also heard from Angel Santana Diaz, WP3GW, of Trujillo Alto, Puerto Rico: “It’s 1000 UTC today March 8, and I only hear noise, a loud ‘SSSHHHHHHhhhhhhh’ on the lower bands. I can’t hear anything on 40 meters, no CW, not even the shortwave AM stations. Now at 1015 UTC, I can barely hear some local Caribbean stations on 7.188 MHz. About this past weekend’s contest, all I can say is, wow! Ten meters was the band to be on, the easiest one where you could park and call all day long. I had 400 QSOs there, breaking last year’s record. Later, I was on 80 meters, and the best time to operate was after 0700 when I did 70 contacts in an hour. In all, I made 103 QSOs, something I’ve never done in a contest. And even though I had only 27 QSOs on 20 meters during the weekend, in less than an hour, I had a chance on 14.189 and did 102 QSOs and as the stations were coming; I’ve never dealt with a pile-up in that way. I felt like a pro attending everybody fast!”
Later Angel reported that conditions were improving fast.
All times listed are UTC, unless otherwise noted.
Amateur solar observer Tad Cook, K7RA, of Seattle, Washington, provides this weekly report on solar conditions and propagation. This report also is available via W1AW every Friday, and an abbreviated version appears each Thursday in The ARRL Letter. You can find a guide to articles and programs concerning propagation here. Check here and here for a detailed explanation of the numbers used in this bulletin. An archive of past propagation bulletins can be found here. You can find monthly propagation charts between four USA regions and 12 overseas locations here. Readers may contact the author via e-mail.