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K7RA's Solar Report

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Last update: Friday, 01-Mar-2024 02:46:32 GMT

SB PROP @ ARL $ARLP009
ARLP009 Propagation DE K7RA
QST DE W1AW
ARRL Propagation Bulletin 9 ARLP009 From Tad Cook, K7RA
Seattle, Washington March 1 2024
To all radio amateurs

"ASWFC GEOMAGNETIC DISTURBANCE WARNING ISSUED AT 2208 UTC/29 FEBRUARY 2024 BY THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE.

"A filament eruption was observed at 28/0855UT from the solar southeast quadrant. The associated CME has been determined to contain an Earth-directed component, with an arrival to Earth's magnetosphere at 02/1100 UTC +/- 12 hours. G1 geomagnetic conditions are expected.

"INCREASED GEOMAGNETIC ACTIVITY EXPECTED DUE TO CORONAL MASS EJECTION FROM 02-03 MARCH 2024"

Seven new sunspot groups emerged this week, four on February 23, one on February 25, another on February 26 and one more on February 28.

Solar activity increased this reporting week, February 22-28, compared to the week before. Average daily sunspot number rose from 84.4 to 108.4, and solar flux from 164 to 175.

Geomagnetic conditions were quiet, though the numbers rose. Planetary A index went from 4.4 to 8.4, and middle latitude numbers from 3.3 to 7.4.

Predicted solar flux 160, 155, and 160 on March 1-3, 165 on March 4-5, 160 and 165 on March 6-7, 165 on March 8-9, 168 on March 10, then 165 on March 11-12, 160 on March 13-14, then 168 and 172 on March 15-16, then 175, 175 and 178 on March 17-19, 180 on March 20-24, and 175 on March 25-26, then 180 and 175 on March 27-28, 170 on March 29-30, 172 on March 31 to April 1, 170 on April 2, and 165 on April 3-5.

Predicted planetary A index is 8, 12, 12 and 10 on March 1-4, then 5 on March 5-23, then 15, 12 and 12 on March 24-26, and 5 on March 27 to mid-April.

. Spaceweather.com reported on giant sunspot AR3590. "In only 23 hours spanning February 21-22, the active region unleashed three powerful X-class solar flares (X1.8, X1.7 and X6.3). The X6.3 flare is the strongest of Solar Cycle 25, so far, and the most powerful flare since the great solar storms of Sept. 2017.'D

Because there were no CMEs, there were no geomagnetic storms, but extreme ultraviolet radiation ionized the top of earth's atmosphere and caused several shortwave blackouts over Hawaii and Australia on February 21-22.

Sunspot group AR3590 is the largest of the current solar cycle.

"Weekly Commentary on the Sun, the Magnetosphere, and the Earth'sIonosphere ' Febrary 29, 2024 from OK1HH.

"Over the past seven days, we have seen the deflection of an active region of AR3590 on the Sun, 760 millionths of the size of the solar disk. On February 25, it already occupied an area of 1450 millionths, making it the largest group of spots so far since the beginning of the 25th cycle. It produced its largest and extra proton flares on February 21-22, including three X-class flares in 23 hours. The largest of these, X6.3 on 22 February, with a maximum at 2324 UT, was the most important flare since the beginning of Cycle 25.

Proton flares were no exception and caused an absorption in the polar cap (PCA). The first of these was recorded on 9 February in the already setting region AR3575. At the same time, there was a region AR3576 in the southeast of the solar disk, which will rise again in the next few days, so we do not have to worry about a decrease in solar activity.

With the exception of the unsettled days of February 25-27, the geomagnetic field was mostly calm. We expect a similar pattern in the coming weeks. Ideally, the mostly calm development could last until the spring equinox. If this happens, shortwave propagation conditions will be mostly above average.

This weekend is the ARRL International DX SSB contest. See:

https://www.arrl.org/arrl-dx

Some solar basics:

https://www.ktvh.com/news/weather-wise/weather-wise-sunspots

https://bit.ly/49AmNKf

https://bit.ly/3V0biHJ

https://bit.ly/3wE1Orx

https://star-hunter.ru/en/sunspots-2024-02-28/

Minima

https://www.popsci.com/science/sun-quiet/

I do not trust the data or the correlations in this article, but there is some interesting content here:

https://bit.ly/48Ablxc

News from Dr. Tamitha Skov

https://youtu.be/V-PQSkYYEB4

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.

https://bit.ly/3Rc8Njt

Instructions for starting or ending email distribution of ARRL bulletins are at http://arrl.org/bulletins .

Sunspot numbers for February 22 through 28 2024 were 46, 116, 106, 114, 133, 103, and 127, with a mean of 106.4. 10.7 cm flux was 173.3, 172.9, 179.2, 180.8, 171.7, 168.3, and 179.1, with a mean of 175. Estimated planetary A indices were 6, 3, 7, 13, 11, 13, and 6, with a mean of 8.4. Middle latitude A index was 6, 2, 6, 14, 10, 9, and 5, with a mean of 7.4. NNNN


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