[SFDXA] ARLP031 Propagation de K7RA

Fri Aug 1 17:23:47 EDT 2014

> SB PROP @ ARL $ARLP031
> ARLP031 Propagation de K7RA
> 
> ZCZC AP31
> QST de W1AW  
> Propagation Forecast Bulletin 31  ARLP031
> From Tad Cook, K7RA
> Seattle, WA  August 1, 2014
> To all radio amateurs 
> 
> SB PROP ARL ARLP031
> ARLP031 Propagation de K7RA
> 
> Spaceweather.com reports that a CME is coming toward us from the sun
> since July 30 when a magnetic filament erupted. It may sideswipe our
> magnetic field on Saturday, August 2, and there is a thirty percent
> chance of geomagnetic storms in polar regions.
> 
> Right now there are plenty of sunspots, but they are magnetically
> weak.
> 
> Since July 24, the Dominion Radio Astrophysical Observatory in
> Penticton, British Columbia has been experiencing some serious
> computer network issues, I think involving a severed fiber optic
> cable. As a result, we do not have a source for the 10.7 cm. solar
> flux values resolved to one-tenth of a point. This is not a serious
> problem, except those of us who archive the values like to see the
> values in a consistent format. We can still get the flux values
> resolved to whole integers from NOAA:
> 
> http://www.swpc.noaa.gov/ftpdir/latest/DSD.txt
> 
> These numbers appear at the end of the weekly bulletin. For those
> who archive the values, when the Penticton site goes back online you
> will be able to correct the values from these usual sources:
> 
> http://www.spaceweather.ca/solarflux/sx-5-flux-eng.php
> 
> ftp://ftp.geolab.nrcan.gc.ca/data/solar_flux/daily_flux_values/fluxtable.txt
> 
> The official flux number is the daily local noon value, which is at
> 2000 UTC. When the system comes back online, you should see solar
> flux readings after July 23. NOAA has always presented these as
> whole integers, and for the past week the noon flux has been
> supplied via a daily phone call to Boulder from Penticton.
> 
> Using the flux values rounded to whole integers makes little
> difference. For example, rounding to whole integers would change the
> average solar flux in ARLP027 from 129.5 to 129.6, and in ARLP028 it
> does not change the average at all.
> 
> Thank goodness there were no zero-sunspot days over the past week,
> so the average daily sunspot number rose from 25.9 in the July 17 to
> 23 period to 107.7 this week. Average daily solar flux rose from
> 90.3 to a more robust 125. Solar flux on Thursday, July 31 was 156.
> 
> July ended yesterday, so we can look at recent averages. The average
> daily sunspot number for July was 113.6, up from 107.8 for June. The
> three month moving averages of daily sunspot numbers for the past
> year are 85.6, 77.4, 91.2, 102.9, 123.7, 123.3, 138.5, 146.4, 148.2,
> 129.6, 118.4 and 112.8.
> 
> Predicted solar flux for the near term is 160 on August 1 and 2, 150
> on August 3, 145 on August 4 to 6, then 140, 120, 110, 105, 100 and
> 95 on August 7 to 12, 90 on August 13 to 15, 95 on August 16 and 17,
> 100 on August 18, and 105 on August 19 to 21.
> 
> From July 21 to 27 the flux value predicted for August 18 was only
> 85, but that was revised back to 100 on July 28, the same value
> predicted from July 13 to 20 (for August 18. Is that clear as mud?)
> 
> Predicted planetary A index is 5, 8, 14, 10, and 8 on August 1 to 5,
> then 5, 8, 6, 5 and 8 on August 6 to 10, 5 on August 11 to 21, then
> 8, 5, 12 and 10 on August 22 to 25, and 5 on August 26 to 31.
> 
> F. K. Janda, OK1HH predicts mostly quiet geomagnetic conditions
> August 1, quiet to unsettled August 2 and 3, quiet to active August
> 4, quiet to unsettled August 5 and 6, quiet August 7, quiet to
> active August 8, active to disturbed August 9, quiet to active
> August 10 and 11, quiet August 12 to 15, mostly quiet August 16,
> quiet August 17 and 18, mostly quiet August 19 and 20, quiet August
> 21, quiet to unsettled August 22, quiet to active August 23 and
> active to disturbed on August 24.
> 
> Scott Bidstrup, TI3/W7RI commented, "You wrote: 'No sunspots? Sky
> and Telescope recommends observing faculae.'
> 
> There's actually a good reason for hams to do so. Faculae actually
> appear fairly bright in the 304 angstrom wavelength images of the
> sun. When they are large and numerous, even in the absence of
> significant sunspots, they can contribute significantly to the 304
> angstrom ultraviolet that causes about half of our F2 ionization. So
> when the sunspots are low, but the propagation isn't all that bad,
> it's a good bet that there are a lot of faculae present on the solar
> disk.
> 
> You can easily see if this is the case in the 304 angstrom image of
> the sun, which can be found on my propagation web page at
> http://www.bidstrup.com/w7ri-hf-radio-propagation.htm . The 304a
> image is the upper right in the group of four solar images (the
> image can be viewed full size by right-clicking the image and
> selecting "view image" from the drop-down menu). Sunspots normally
> appear as a bright, white spot in this image, but faculae appear as
> bright orange areas surrounding the sunspots, much brighter than the
> background granulation around them. The faculae may not be as bright
> as the sunspots, but they make up for that in a much larger area on
> the solar surface.
> 
> While the faculae don't show up quite as well in the 195 angstrom
> image from the STEREO B spacecraft beacon, the green image just
> below the 304a image on my page, it will give you an idea of what
> faculae as well as active regions are about to rotate into view. So
> it can be useful to watch these images to get an idea of what is
> coming up - particularly for a contest weekend - it can help in
> planning band strategies."
> 
> Thanks Scott!
> 
> Tomas Hood, NW7US, the propagation editor for CQ and several other
> magazines, is publishing cool propagation and space weather
> information throughout each day on his Space Weather and Radio
> Propagation page on Facebook (see https://www.facebook.com/spacewx.hfradio ).
> 
> These posts include current images from the Solar Dynamics
> Observatory (SDO) instruments that watch the Sun 24/7, daily space
> weather and radio propagation conditions and forecasts, plus
> educational tidbits that can enhance your understanding of this
> exciting topic. Anyone who has a Facebook account can 'Like' and
> have notifications turned on so that you can see alerts when these
> page posts are made. Speaking of educational material, check out the
> self-study course that Tomas is offering at http://nw7us.us/swc .
> 
> 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 July 24 through 30 were 55, 65, 76, 110, 143,
> 160, and 145, with a mean of 107.7. 10.7 cm flux was 104, 107, 117,
> 121, 132, 142, and 152, with a mean of 125. Estimated planetary A
> indices were 5, 6, 7, 5, 9, 4, and 5, with a mean of 5.9. Estimated
> mid-latitude A indices were 6, 9, 9, 6, 12, 6, and 7, with a mean of
> 7.9.
> NNNN
> /EX