7-14-22 Solar report

Tad Cook, K7RA, of Seattle, Washington, reports for this week’s ARRL Propagation Bulletin ARLP028:

Rising solar activity over the past reporting week, July 7 – 13, 2022, was reflected in increased sunspot numbers, solar flux, and rising geomagnetic activity.

Average daily sunspot numbers increased from 62.6 to 102.1, with the peak value at 134 on Monday, July 11. Average daily solar flux rose from 103.5 to 147.4, with peak values at 164.9 and 164.8 on Tuesday and Wednesday.

New sunspots emerged on July 7, July 10, and July 11. Total sunspot area peaked on July 11.

Planetary A index averaged out at 12.4 (up from 9.8 last week) while the middle latitude A index went from 9.7 to 10.6.

Toward the end of the day on July 7, Alaska’s college A index was 46 (a very high value), while the last four K index readings of the same day and the next two were 6, 6, 7, 5, 5, and 5.

This was caused by a corotating interaction region, sparking a G1-class geomagnetic storm.

Visit the following links for info on corotating interaction regions:

https://bit.ly/3P91Xrp

https://bit.ly/3IBOtlm

https://bit.ly/3yDwxlU

The Wednesday-night prediction from the United States Air Force shows solar flux at 165 on July 14 – 15; 160 on July 16 – 18; and 155, 150, and 135 on July 19 – 21. A prediction of 130 is shown July 22 – 24; 138 and 148 on July 25 – 26; 150 on July 27 – 29; 160 on July 30 – August 7; and 155, 145, and 135 on August 8 – 10. August 11 – 12 is 138, then 128 and 125 on August 13 – 14, and 130 on August 15 – 17.

Predicted planetary A index is 8 on July 14 – 21, then 15, 20, and 12 on July 22 – 24. Eight is predicted again on July 25 – August 2, then 12 and 10 on August 3 – 4, and 8 on August 15 – 17.

I often see news items that mention solar flares and are written as though the world is about to end.

A few recent examples, for our collective amusement:

https://bit.ly/3yCXV3h

https://bit.ly/3RA5Bfy

https://bit.ly/3P5KakF

Sunspot numbers for July 7 – 13, 2022, were 80, 81, 89, 113, 134, 117, and 101, with a mean of 102.1. The 10.7-centimeter flux was 121.3, 129.6, 136.9, 153, 161, 164.9, and 164.8, with a mean of 147.4. Estimated planetary A indices were 20, 19, 6, 7, 12, 18, and 5, with a mean of 12.4. Middle latitude A index was 15, 14, 6, 8, 10, 16, and 5, with a mean of 10.6.

Send your tips, questions, or comments to k7ra@arrl.net.

A comprehensive K7RA Solar Update is posted Fridays on the ARRL website. For more information concerning radio propagation, visit the ARRL Technical Information Service, read “What the Numbers Mean…,” and check out the Propagation Page of Carl Luetzelschwab, K9LA.

A propagation bulletin archive is available. For customizable propagation charts, visit the VOACAP Online for Ham Radio website.

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