[SFDXA] ARLP001 Propagation de K7RA

[William Marx]

> SB PROP @ ARL $ARLP001
> ARLP001 Propagation de K7RA
> 
> ZCZC AP01
> QST de W1AW  
> Propagation Forecast Bulletin 1  ARLP001
> From Tad Cook, K7RA
> Seattle, WA  January 4, 2013
> To all radio amateurs 
> 
> SB PROP ARL ARLP001
> ARLP001 Propagation de K7RA
> 
> The New Year brings dreams of solar cycles of old, so distant now,
> sweetly remembered for their profusion of sunspots. We hear many
> times from operators who began in the amateur radio service as
> teenagers at the peak of Cycle 19. With youthful optimism, they
> naturally assumed that radio propagation would always be like that,
> when a few watts and a modest radiator on 10 meters spanned the
> globe during all the days and nights.
> 
> If you were age 13 to 17 in 1957 to 1959, the peak of Cycle 19,
> perhaps you were born between 1941 and 1945, and probably looked
> forward to the next peak in activity. That may have been a
> disappointment when Cycle 20 peaked around 1969, as that had a
> somewhat broader peak but at a far lower level. You can see it
> graphically at http://wm7d.net/hamradio/solar/historical.shtml.
> These young adults, now 24 to 28 years old in 1969, might be busy
> starting families and careers, and no doubt fondly recalling simpler
> times and the tremendous propagation of their younger years.
> 
> Cycle 21 peaked around 1980, and the former teenaged ham of Cycle 19
> was now 35 to 39 years old. This was quite an improvement over the
> last cycle, as was Cycle 22, which looked like an echo of Cycle 21.
> Cycle 22 peaked around 1991-1992, with a more pronounced
> double-peak. The former teenager was now 47 to 51 years old, solidly
> into middle-age, and still wondering if sunspot activity would ever
> roar back to the levels of the late-1950s.
> 
> The following cycle, number 23, was another double-peak, but
> significantly lower in 2000 to 2002 than the previous cycle. Perhaps
> another disappointment for the now 56 to 60 year old ham, who then
> sees solar activity slide into a long and low minimum over the next
> decade, impossible to imagine 60 years earlier. The 160 meter
> operators, quite happy in this situation with a much quieter Sun,
> have no such longing for the active Sun of yesteryear.
> 
> Now the young ham of the late 1950s contemplates the peak of Cycle
> 24, apparently much lower than any seen in most of the past century,
> and expected to grow to maximum this year. Now we have many more
> tools to observe and measure both solar activity and propagation,
> and we know that activity could still increase significantly. Some
> foresee decades of lower activity, but of course predicting future
> solar activity is a very tricky proposition, and anything could
> happen.
> 
> At
> http://www.solen.info/solar/images/comparison_recent_cycles.png
> you can see a comparison of recent cycles, from 21 to the current
> 24.
> 
> While we've seen a number of papers and predictions for a series of
> quieter sunspot cycles, some disagree. For instance, Michael
> Proctor, professor of Astrophysical Fluid Dynamics at Cambridge
> University is not convinced. He was quoted this year as saying,
> "This present cycle is similar to the weak one that ended in 1913,
> and that was followed by a strong cycle."
> 
> Those were Cycles 14 and 15, and Cycle 15 was only strong relative
> to 14. Cycles 17, 18 and 19 were stronger than 15, and so were 21,
> 22 and 23.
> 
> It is also important to remember there is wild variability in solar
> activity. To make those graphs of sunspot numbers appear smooth,
> each point on the graph actually represents an average of a year of
> data. When averaged, the flurry of solar activity at the end of 2011
> and some future activity in 2013 could appear as a broad peak on a
> graph.
> 
> NASA looks frequently at their predictions for the current cycle,
> and often adjusts them every month. The latest shows a smoothed
> sunspot number a bit lower than the forecast from several weeks ago.
> In the December 10 forecast they predicted a smoothed sunspot number
> of 72 in the late in 2013, but that number is now 69 in the January
> 2 release. Note these are the lower international sunspot numbers,
> which are always less than Boulder numbers presented in this
> bulletin. Read the report at
> http://solarscience.msfc.nasa.gov/predict.shtml.
> 
> With the change from 2012 to 2013, now is a good time to review
> sunspot numbers and trends. Average daily sunspot numbers in 2013
> were up substantially from 2012. From 2004 through 2012 the yearly
> progression was 68.6, 48.9, 26.1, 12.8, 4.7, 5.1, 25.5, 29.9 and
> 82.3. I took all the daily sunspot numbers for 2012, added them
> together, and the sum was 30,133. Divide that by 366 (the number of
> days in 2012, a leap year) and the result is approximately 82.3. In
> 2011 it was 10,913 divided by 365, yielding 29.9.
> 
> The 2012 average was higher than any year after 2003. But at the
> peak of Cycle 23, the averages from 1998 to 2003 were all higher:
> 88.7, 136.3, 173, 170.3, 176.7, and 109.2. It seems unlikely that
> average daily sunspot numbers this year will reach anywhere near the
> level of 2000-2002.
> 
> We observe a moving 3-month average of sunspot numbers, in an
> attempt to smooth out some of the variations. Unfortunately, the
> past three months were much lower then the three month period ending
> one month earlier. The current average of 74.4, centered on November
> 2012, is lower than any three month period since averages centered
> on February and March of 2012.
> 
> The 3 month period previous to the current one is centered on
> October 2012, and covers September through November. The average
> then was 82.3. To recap averages from previous bulletins, the
> three-month moving averages of daily sunspot numbers centered on
> July 2011 through November 2012 were 63, 79.6, 98.6, 118.8, 118.6,
> 110, 83.3, 73.7, 71.2, 87.3, 91.5, 96.5, 91.9, 89.9, 81.2, 82.3, and
> 74.4.
> 
> Looking at the past week, yesterday we saw a sizable gain in solar
> flux, when the value went from 106.7, 113.6, 117.8, and 119 to
> 128.8, on December 30 through January 3. NOAA and USAF predict solar
> flux at 130 on January 4-6, 125 and 120 on January 7-8, 115 on
> January 9-10, 110 on January 11, 105 on January 12-13, 110 on
> January 14-17, 115 on January 18-20, and 120 on January 21-23.
> 
> Predicted planetary A index is 5 on January 4-12, 10 on January 13,
> 5 on January 14-25 and 8 on January 26.
> 
> F.K. Janda, OK1HH issues a weekly geomagnetic forecast. This week he
> says geomagnetic conditions will be quiet January 4, quiet to active
> January 5, mostly quite January 6, quiet January 7-9, quiet to
> unsettled January 10-12, active to disturbed January 13, quiet to
> unsettled January 14-16, quiet January 17-19, mostly quiet January
> 20-21, and quiet on January 22-26.
> 
> If you would like to make a comment or have a tip for our readers,
> email the author at, k7ra at arrl.net.
> 
> For more information concerning radio propagation, see the ARRL
> Technical Information Service web page 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. Find more good
> information and tutorials on propagation at
> http://myplace.frontier.com/~k9la/.
> 
> 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 December 27 through January 2 were 78, 54, 49,
> 37, 87, 99, and 90, with a mean of 70.6. 10.7 cm flux was 106.8,
> 105.8, 104.3, 106.7, 113.6, 117.8, and 119, with a mean of 110.6.
> Estimated planetary A indices were 1, 2, 3, 4, 2, 1, and 3, with a
> mean of 2.3. Estimated mid-latitude A indices were 0, 2, 3, 4, 1, 1,
> and 2, with a mean of 1.9.
> NNNN
> /EX