08/12/2022

Solar activity did a rebound this week, back to more active levels.

Average daily sunspot number increased from 36.6 to 65.4.

Average daily 10.7 cm solar flux rose from 95.7 to 111.9.

Solar wind caused geomagnetic numbers to rise, with average planetary A index
going from 7.7 to 14.4, and middle latitude numbers from 8.6 to 12.1.

An improved outlook shows solar flux over the next month peaking at 116 on
September 2 to 4.  The forecast from USAF/NOAA on Thursday evening was improved
from Wednesday.

A look at ARLP032 from 2021 gives a perspective on solar cycle progress.  A
year ago, average sunspot number was 6 and average solar flux was just 74.8. 
Quite a difference from 65.4 and 111.9 during the past week.

Predicted flux values are 115 on August 12 to 14, 110 on August 15 to 18, 108
on August 19, 104 on August 20 and 21, then 98, 100, 102, 100, 102, and 100 on
August 22 to 27, then 102 on August 28 to 30, then 108 and 114 on August 31 and
September 1, 116 on September 2 to 4, 112 on September 5 to 7.  110 on
September 8 and 9, then 108 on September 10 to 12, 106 on September 13, then
104 on September 14 to 16, 102 on September 17 and 98 on September 18.

Predicted planetary A index is 12 on August 12, 5 on August 13 to 16 then 10,
12 and 15 on August 17 to 19, 8 on August 20 and 21, 5 on August 22 to 26, 12
on August 27, 8 on August 28 to 30, 5 on August 31 through September 2, then
14, 18, 14, 10 and 8 on September 3 to 7, and 5 on September 8 to 12, then 22
on September 13, 15 on September 14 and 15, 8 on September 16, and 5 on
September 17 to 22.

OK1HH commented:

"A geomagnetic disturbance rarely comes completely unexpectedly. And even more
so in a situation where its source cannot be located (or selected from several
locations).  Moreover, lasting five days. All this happened between August 7th
and 11th.

At higher latitudes, the 'STEVE' phenomenon was sighted on August 7 (Strong
Thermal Emission Velocity Enhancement).  STEVE is a recent discovery.  It looks
like an aurora, but it's not.

https://en.wikipedia.org/wiki/STEVE[1]

It all started with a positive phase of disturbance in the ionosphere, when
shortwave propagation improved.  The development continued with a deterioration
of propagation in the negative phase on August 8, followed by generally below
average conditions in the following days.  With a strong influence of sporadic
layer E, whose activity usually increases as the Perseids meteor shower
approaches maximum (expected on 12 and 13 August).  They are also called the
'Tears of St. Lawrence'.

Starting August 12 onward, we expect a longer mostly quiet period."

NASA expects increasing activity:

https://bit.ly/3QjOLk5[2]

Always appreciate The Sun Now page from the Solar Dynamics Observatory:

https://sdo.gsfc.nasa.gov/[3]

Yet another cycle prediction method:

https://bit.ly/3SKm29J[4]

Tamitha Skov, WX6SWW has a 200 minute part 2 of a course on ground effects:

https://youtu.be/cOom5LQ_LBY[5]

Send your tips, reports, observations, questions and comments to
k7ra@arrl.net[6].

For more information concerning shortwave radio propagation, see
http://www.arrl.org/propagation[7] and the ARRL Technical Information Service
at http://arrl.org/propagation-of-rf-signals[8]. For an explanation of numbers
used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[9]

An archive of past propagation bulletins is at

http://arrl.org/w1aw-bulletins-archive-propagation[10]. More good information
and tutorials on propagation are at http://k9la.us/[11]

Instructions for starting or ending email distribution of ARRL bulletins are at
http://arrl.org/bulletins[12].

Sunspot numbers for August 4 through 10, 2022 were 52, 69, 69, 87, 63, 58, and
60, with a mean of 65.4.  10.7 cm flux was 108.8, 112.2, 116.3, 116.1, 113,
109.4, and 107.6, with a mean of 111.9.  Estimated planetary A indices were 6,
6, 4, 24, 31, 19, and 11, with a mean of 14.4.  Middle latitude A index was 7,
7, 5, 20, 21, 15, and 10, with a mean of 12.1.

[1] https://en.wikipedia.org/wiki/STEVE
[2] https://bit.ly/3QjOLk5
[3] https://sdo.gsfc.nasa.gov/
[4] https://bit.ly/3SKm29J
[5] https://youtu.be/cOom5LQ_LBY
[6] mailto:k7ra@arrl.net
[7] http://www.arrl.org/propagation
[8] http://arrl.org/propagation-of-rf-signals
[9] http://arrl.org/the-sun-the-earth-the-ionosphere
[10] http://arrl.org/w1aw-bulletins-archive-propagation
[11] http://k9la.us/
[12] http://arrl.org/bulletins

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