ARLP033 Propagation de K7RA
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SB PROP @ ARL $ARLP033
ARLP033 Propagation de K7RA
ZCZC AP33
QST de W1AW
Propagation Forecast Bulletin 33 ARLP033
From Tad Cook, K7RA
Seattle, WA August 15, 2014
To all radio amateurs
SB PROP ARL ARLP033
ARLP033 Propagation de K7RA
Solar activity showed further signs of weakness this week, with the
average daily sunspot number dropping 41.8 points to 94.9, while
average daily solar flux declined 36.5 points to 113.1.
In the 45-day forecast for solar flux, it was surprising back on
August 3 to see a new solar flux prediction of 150 for August 31
through September 3. I suspected this prediction would come down to
a lower level, more in line with predicted values before and after
that period, and in the August 11 forecast, that is what happened.
The predicted solar flux for those dates was changed to 125 on
August 31 through September 2, then 120 on September 3, where it
remains today.
From that 45-day forecast, solar flux at 105 is predicted for August
15, 110 on August 16 to 18, 105 on August 19 and 20, then 100 and
110 on August 21 and 22, 115 on August 23 and 24, 120 on August 25
and 26, then 125 and 130 on August 27 and 28, 125 on August 29
through September 2, 120 and 115 on September 3 and 4, and 110 on
September 5 to 7. Flux values are expected to go as low as 100 on
September 13 to 16, then rise to 135 by September 24, the day
following the fall equinox.
Predicted planetary A index is 8 on August 15 and 16, 5 on August 17
to 23, 8 on August 24, 5 on August 25 to 27, 8 on August 28 and 29,
then 5, 12, 10 and 8 on August 30 through September 2, 5 on
September 3 to 5, 8 on September 6, 5 on September 7 and 8, 8 on
September 9, and 5 until September 18.
Not all looks weak or bleak. On Thursday, August 14 there were four
new sunspot regions emerging. We have not seen four or more new
regions emerge in one day since December 31, 2013. And solar
activity is certainly higher now than it was a year ago. Average
daily sunspot numbers for propagation bulletins 31-33 this year
(representing the past three weeks) were 107.7, 136.7 and 94.9. For
the same weeks in 2013 the averages were 79.6, 85.4 and 85.
OK1HH believes we should expect quiet to unsettled geomagnetic
conditions on August 15, mostly quiet conditions August 16, quiet on
August 17 and 18, mostly quiet August 19 to 21, quiet to unsettled
August 22, active to disturbed August 23, quiet to unsettled August
24, mostly quiet August 25, quiet to active August 26 to 29, active
to disturbed August 30, quiet to active August 31, mostly quiet
September 1 and 2, quiet to unsettled September 3, quiet September 4
and 5, quiet to unsettled September 6, quiet on September 7, mostly
quiet September 8, and quiet to unsettled September 9. He thinks we
will see increased solar wind on September 7 to 9.
Scott Bidstrup, TI3/W7RI sent this report:
"In spite of the recent uptick in solar activity, there has been
only a modest improvement in propagation here in the low latitudes.
Ten meters has been open for several days during the first week of
this month, but little before or since. Six has been entirely dead,
and most of the avid six meter aficionados have pretty much given up
for now. Often we will see TES openings from here into Brazil,
Argentina and Chile on a daily basis for a month or so, beginning
about now, but so far the propagation has been late to appear. Given
the bust that this year's Es season into the States has been, we're
not terribly hopeful, especially with the 304a index headed down
again.
The improved conditions on 75 meter DX have been continuing, but
oddly enough, it's been almost entirely into VK/ZL and adjacent
areas of the South Pacific from here. Normally, we'd be working
Japan on gray line every day, but there've been just a few openings
so far this season. The Intertropical Convergence Zone has been
exceptionally active this year, and so atmospheric noise levels have
been downright brutal - S9+30 on many mornings, and rarely below
S9+10. This may account for the lack of Qs with Japan. We have yet
another two months of high thunderstorm activity, and everyone's
already looking forward to an end to it. 73 and best regards from
rainy Costa Rica."
Scott also sent along this article, about using techniques from
weather forecasting to aid in predicting solar cycles:
http://www2.ucar.edu/atmosnews/just-published/12097/next-step-toward-predicting-sun-cyclesPenn State has an article and impressive video on the 2.5 meter
telescope at Apache Point Observatory, Sunspot, New Mexico. Read
about it here:
http://news.psu.edu/video/322684/2014/08/12/research/sloan-foundation-25m-telescope-apache-point-observatory-sunspot-newThe video on that page is a wonderful time-lapse movie of this very
busy telescope over one night. Be sure to select the HD option and
expand to full screen. Watch the stars track across the sky, while a
technician scurries around tending to this telescope. Eventually the
sun rises. Separately, the video is available at:
https://www.youtube.com/watch?feature=player_embedded&v=AHsS57NMQjEHere is a great big representation of smoothed sunspot numbers, back
to 1985, for cycles 22 to 24. Note you can click on it to make it
appear even larger:
http://solarscience.msfc.nasa.gov/images/Cycle22Cycle23Cycle24big.gif David Moore of Morro Bay, California frequently sends interesting
items about our sun, and here is one explaining why the sun's
atmosphere is so much hotter than its surface:
http://www.sciencealert.com.au/news/20140408-25970.htmlFor more information concerning radio propagation, see the ARRL
Technical Information Service at
http://arrl.org/propagation-of-rf-signals. For an explanation of the
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/.
Monthly propagation charts between four USA regions and twelve
overseas locations are at
http://arrl.org/propagation.
Instructions for starting or ending email distribution of ARRL
bulletins are at
http://arrl.org/bulletins.
Sunspot numbers for August 7 through 13 were 158, 101, 111, 64, 82,
80, and 68, with a mean of 94.9. 10.7 cm flux was 136, 123, 113,
108, 105, 104, and 103, with a mean of 113.1. Estimated planetary A
indices were 6, 8, 4, 9, 7, 12, and 6, with a mean of 7.4. Estimated
mid-latitude A indices were 6, 9, 4, 9, 7, 11, and 8, with a mean of
7.7.
NNNN
/EX
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