[SFDXA] ARLP033 Propagation de K7RA

Fri Aug 15 17:45:09 EDT 2014

> 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-cycles 
> 
> Penn 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-new
> 
> The 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=AHsS57NMQjE
> 
> Here 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.html
> 
> For 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