The K7RA Solar Update

Tad Cook, K7RA, Seattle, reports: Solar activity was weaker over the February 24 – March 2 reporting week, with the average daily sunspot number weakening from 54.3 to 44, but average daily solar flux rising slightly from 95.4 to 98.5.

Geomagnetic numbers were moderate. Average daily planetary A index declined from 9.6 to 7.3, and middle latitude index from 7.3 to 5.6.

Predicted solar flux is 110 on March 4; 108 on March 5 – 7; 106, 104, and 100 on March 8 – 10; 99 on March 11 – 13; 98 on March 14; 95 on March 15 – 16; 96, 97, 98, and 99 on March 17 – 20; 100 on March 21 – 22; 101 and 100 on March 23 – 24; 102 on March 25 – 26; 99 and 102 on March 27 – 28; 105 on March 29 – 31; 102 on April 1 – 2, 101 on April 3 – 4; 100 on April 5 – 6, and 99 on April 7 – 9.

Predicted planetary A index is 12 on March 4 – 6; 10 on March 7; 5 on March 8 – 10; 10, 12, 8, 5, and 8 on March 11 – 15; 5 on March 16 – 17; 10 on March 18; 15 on March 19 – 21; 7 on March 22 – 24; 5 and 10 on March 25 – 26; 12 on March 27 – 28; 8 on March 29 – 30; 12 on March 31; 15 on April 1 – 2; 5 on April 3 – 6, and 18, 15, and 8 on April 7 – 9.

Here’s the weekly commentary from F.K. Janda, OK1HH:

“The decline in solar activity in the second half of February might have surprised us if it were not for the information about the increased eruptive activity on the far side of the sun. The far-side sunspots images were taken mainly by the STEREO-A spacecraft, starting with the huge far-side explosion, when the spacecraft recorded a spectacular coronal mass ejection (CME) appearing in the late hours of February 15. One day later, Solar and Heliospheric Observatory (SOHO) gave us a better view of the explosion on the far side. SOHO coronagraphs have recorded the most dramatic CME in recent years. The activity observed beyond the eastern edge of the solar disk looked promising several times, but after the spot groups actually came out, we experienced only occasional Class C eruptions. Earth’s magnetic field activity fluctuated irregularly, and attempts to predict further developments failed. Conditions for HF propagation began to improve in early March, but this was mainly due to seasonal changes.”

The article “DKIST, Our Biggest Eye on the Sun, is Ready to Bring the Science,” appears on the SyFy.com site.

Also, check out the solar orbiter from the European Space Agency.

Jeff, WA2BOT, in Connecticut wrote on March 2:

“Wow! 10 meters long path from East Coast USA to the Far East was amazing today! I noticed 10 meters was open to Europe at 1143 UTC when I first checked band conditions. Operating FT8 from FN32 between 1310 GMT and 1348 GMT, I worked BD7MXA, VR2XYL, VR2ZXP, VR2UBC, VR2XRW, VR2CH, JA7QVI and 12 other stations in Japan.

Solar Cycle 25 is just getting started and 10 meters is Wow!”

The subject of an article on Science Alert is “Stunning Loops of Plasma Observed on the Sun May Not Be What We Thought.”

Here’s a 2020 study regarding the terminator event, “Overlapping Magnetic Activity Cycles and the Sunspot Number: Forecasting Sunspot Cycle 25 Amplitude,” on Springer Link.

Now, the authors have announced “The Termination Event has Arrived” — the terminator event between sunspot Cycles 24 and 25.

Sunspot numbers for February 24 – March 2 were 23, 22, 22, 48, 65, 62, and 66, with a mean of 44. The 10.7-centimeter flux was 92.3, 96.2, 96.5, 96.9, 99, 99.3, and 109.5, with a mean of 98.5. Estimated planetary A indices were 7, 8, 3, 13, 8, 8, and 4, with a mean of 7.3. Middle latitude A index was 6, 7, 1, 11, 5, 6, and 3, with a mean of 5.6

For more information concerning radio propagation, visit the ARRL Technical Information Service, read “What the Numbers Mean…,” and check out this propagation page by Carl Luetzelschwab, K9LA.

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

Instructions for starting or ending email distribution of ARRL bulletins are on the ARRL website.

Share your reports and observations.

source:ARRL