Tad Cook, K7RA, of Seattle, Washington, reports for this week’s ARRL Propagation Bulletin, ARLP035:
| Solar disc image taken September 1, 2022, courtesy of NASA SDO/HMI. |
The past week saw many interesting events. The observatory at Penticton, British Columbia (the source of 10.7-centimeter solar flux measurements) was overwhelmed by solar flares, and at 2000 UTC on August 28, reported a solar flux value of 251.9. The next day at 1700 UTC, 357.1 was reported. The 2000 UTC local noon numbers are the official solar flux number for each day, so for the August 28 value, I chose to report the 2300 UTC number of 133.5.
I checked with astronomer Andrew Gray at Penticton. He reported, ”The high values are indeed because of solar activity. Both yesterday and today, flares occurred right during our flux measurements.”
Solar activity increased this reporting week (August 25 – 31) with average daily sunspot numbers increasing from 58.7 to 74.9, and solar flux from 104.5 to 123.8.
Without that correction for August 28, the average daily solar flux would have been 140.8 instead of 123.8.
The average daily A index was a little lower, as the planetary values shifted from 12.6 to 10.1 and the middle latitude went from 11 to 9.4.
Three new sunspot groups appeared on August 25 at the beginning of the week, but none have appeared since then.
The predicted solar flux is 110 on September 1 – 2; 115 on September 3 – 5; 110 on September 6 – 7; 115, 120, and 124 on September 8 – 10; 130, 128 and 120 on September 11 – 13; 117, 105, and 102 on September 14 – 16; 98 on September 17 – 18; 104, 102, and 108 on September 19 – 21; 118 on September 22 – 23; 124 and 125 on September 24 – 25; 120 on September 26 – 28; 115 on September 29 to October 1, and 112 on October 2.
The predicted planetary A index is 5 on September 1 – 2; 8, 20, 25, and 15 on September 3 – 6; 10 on September 7 – 8; 12 and 8 on September 9 – 10; 5 on September 11 – 12; 12, 15, and 10 on September 13 – 15; 8 on September 16 – 17; 5 on September 18 – 23; 14, 10, and 8 on September 24 – 26; 5 on September 27 – 29, and 30, 38, and 20 on September 30 through October 2.
The sunspot numbers for August 25 through 31, 2022, were 94, 88, 84, 79, 87, 50, and 42 with a mean of 74.9. The 10.7-centimeter flux was 117.8, 118.6, 127.5, 133.5, 130.6, 125.6, and 113.3, with a mean of 123.8. The estimated planetary A indices were 5, 5, 14, 7, 14, 13, and 13, with a mean of 10.1. The middle latitude A index was 5, 5, 11, 7, 13, 13, and 12, with a mean of 9.4.
ARRL News Letter on September 1, 2022