ARRL Propagation Report
|
SB PROP @ ARL $ARLP001
ARLP001 Propagation de K7RA ZCZC AP01 QST de W1AW Propagation Forecast Bulletin 1 ARLP001 From Tad Cook, K7RA Seattle, WA January 5, 2024 To all radio amateurs SB PROP ARL ARLP001 ARLP001 Propagation de K7RA Only four new sunspot groups emerged over the past week, one on December 28, another on December 31, and two more on January 2 and 3. Solar indices sank. The average daily sunspot number declined from 114.4 to 63.4, and average daily solar flux from 172.6 to 141.9. Average daily planetary A index rose from 8.4 to 6.7 and middle latitude numbers from 4 to 5.1. Predicted solar flux over the next few weeks is 130 on January 5-7, 135 on January 8-10, 140 on January 11, 155 on January 12-14, then 160, 165, 160 and 155 on January 15-18, 150 on January 19-21, then 145 and 140 on January 22-23, and 135 on January 24-26, 130 and 145 on January 27-28, 140 on January 29-30, 145 on January 31 through February 1, 150 on February 2-4, 155 on February 5-6, 160 on February 7, and 155 on February 8-10. This is from the Thursday forecast, which looks substantially weaker than the Wednesday outlook in Thursday's ARRL Letter. Predicted planetary A index is 5, 5, 8, 10 and 8 on January 5-9, then 5 on January 10-26, then 8, 15 and 12 on January 27-29, 8 on January 30-31, 5 on February 1-3, then 10, 10 and 8 on February 4-6, and 5 on February 7-18. Solar activity looks soft of late, but perhaps we will see a double peak in this cycle. But look at this illustration comparing progress in the current cycle against the last cycle, month by month since each minimum: https://bit.ly/4aMBefh Page down to the second chart, labeled "Solar Cycle Comparison." There is some confusion because of the similarity in colors. The red line is the last cycle, probably smoothed by monthly averages. The blue green line inside it is probably a conventional moving average with points on the line smoothed over a year. The yellow line is the current cycle, also probably smoothed over a year, and the light blue green line is the current cycle, probably smoothed with monthly numbers. This looks promising for more activity to come. Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere, January 4, 2024, from F.K. Janda, OK1HH. "The first celebrations of the end of the calendar year in Western civilization are associated with the person of the canonized Pope Silvester I, who died on the last day of the year 335. However, no one expected that December 31, 2023, would be celebrated with fireworks all the way on the Sun. "Helioseismological observations focused on a large active region approaching the northeastern limb of the solar disk from the far side, and large spots on the far side of the Sun were seen by the camera of the Perseverance rover on Mars. But no one actually expected a proton solar flare, the largest in the current eleven-year cycle. "The X5.0 eruption in X-ray band 1 to 8 Angstrom occurred at 2155 UTC in NOAA/SWPC 3536 and was the largest observed eruption since the X8.2 eruption on September 10, 2017. In the same sunspot group (in the previous solar rotation), an X2.8 eruption was observed on December 14, 2023, whereby this was the strongest since the beginning of Solar Cycle 25 up to that point. "In particular, however, it also contributed to expectations of a further increase in activity in the next year or two. "Four days later, AR3536 is no longer as large as it was on the Sun's far side and about half the size it was in December as AR3514, but it is still capable of producing moderate solar flares. Now AR 3536 is approaching the central meridian from where a possible CME (within the next week) could already be hitting Earth. At the same time, we expect a further increase in solar radiation , which could improve propagation conditions in the DX bands. But of course, also worsen if a possible magstorm lasts longer or even starts at night." I was on a video session on Sunday with Dr. Tamitha Skov and her Patreon subscribers. She was displaying the Sun in real time when the big flare happened. It was quite dramatic. She was also using a setting on Pskreporter.info that I had never tried before. The settings are, "On All Bands, show Signals, sent/rcvd by Anyone, using All Modes, over the last" (pick a time). In real time we could immediately see the effects the flare had on propagation. It was fascinating. I use this regularly now to check worldwide propagation on all HF bands. I asked her if her husband was an astrophysicist, and she said, "No." She yelled, "Hey Kent! Come in here." Kent is an actor, an acting coach, a producer, and a writer. I asked how they met, which was hilarious. You won't read it here, but you can email me if you want more details. Scott Craig, WA4TTK years ago built some Windows software that sucks up solar data from this bulletin and displays it in a nice format on his Solar Data Plotting Utility. To update it, you just create a plain .txt file of this bulletin and point the program to the file. You can download it from http://www.craigcentral.com/sol.asp and also on the same page is an updated data file good through 1/3/2024. The latest video from Dr. Tamitha Skov, WX6SWW: https://youtu.be/WN4iqCq4LAU An article about a powerful solar storm: https://bit.ly/3RO0Ek5 Two articles about a solar storm that will hit hard: https://bit.ly/3vqMhL9 https://bit.ly/41L5SBI Send your tips, reports, observations, questions, and comments to k7ra@arrl.net. When reporting observations, don't forget to tell us which mode you were operating. For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation and the ARRL Technical Information Service web page at, http://arrl.org/propagation-of-rf-signals . For an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere . An archive of past propagation bulletins is at http://arrl.org/w1aw-bulletins-archive-propagation . More good information and tutorials on propagation are at http://k9la.us/ . Also, check this article: https://bit.ly/3Rc8Njt Instructions for starting or ending email distribution of ARRL bulletins are at http://arrl.org/bulletins . Sunspot numbers for December 28, 2023, through January 3, 2024, were 83, 92, 48, 55, 44, 59, and 63, with a mean of 63.4. 10.7 cm flux was 146.7, 142.9, 139.7, 146.2, 135.7, 142.1, and 140.2, with a mean of 141.9. Estimated planetary A indices were 3, 6, 5, 4, 10, 8, and 11, with a mean of 6.7. Middle latitude A index was 2, 6, 4, 2, 6, 8, and 8, with a mean of 5.1. NNNN /EX |