[South Florida DX Association] ARLP002 Propagation de K7RA

[Bill Marx]

 ZCZC AP02
> QST de W1AW
> Propagation Forecast Bulletin 2  ARLP002
> From Tad Cook, K7RA
> Seattle, WA  January 14, 2005
> To all radio amateurs
>
> SB PROP ARL ARLP002
> ARLP002 Propagation de K7RA
>
> For the second reporting week for 2005 (January 6-12) both solar
> flux and sunspot numbers were down, as expressed in the weekly
> averages of the daily numbers. Average daily sunspot numbers
> declined over 9 points to 31.6, and average daily solar flux was
> down over 5 points to 89.9. These are not big point spreads, but at
> this low level of solar activity there isn't much room for decline.
> Eventually over the next two years we will see increasing periods of
> consecutive days with a sunspot count of 0 and solar flux down below
> 70.
>
> The daily solar flux value is an expression of the noontime 2.8 GHz
> energy detected at a sun-pointing receiving antenna in Penticton,
> British Columbia. Canada's Dominion Radio Astrophysical Observatory
> does the measurement, and you can see details along with a history
> of this daily observation at,
> http://www.drao.nrc.ca/icarus/www/history.html. According to my
> records, the lowest daily solar flux value measured over the past
> decade was 64.9, on July 9, 1996. This was during a time when the
> sunspot number was 0.
>
> Solar activity has been rising over the past week. Right after this
> bulletin was put to bed a week ago, the interplanetary magnetic
> field near earth dropped sharply to the south, which made earth
> vulnerable to geomagnetic storms. The geomagnetic indices (A and K
> index) rose sharply from very quiet to very stormy on January 7 and
> 8. A few days later earth was inside a high-speed solar wind, and
> conditions were stormy again on January 12. Fast growing sunspot 720
> emerged, and this should increase the sunspot number and solar flux
> over the next few days. See,
> http://spaceweather.com/images2005/14jan05/midi512_blank.gif for a
> January 14 view of this fast growing spot.
>
> Solar flux is predicted at 120 for January 14-15, and around 125 for
> January 16-20. This is a sharp increase over the average daily value
> of 89.9 for the past week and 95.4 for the previous week. Solar flux
> values around 120-125 suggest daily sunspot numbers rising toward
> (but not reaching) 100. Unsettled to active geomagnetic conditions
> are predicted for January 14, and quiet conditions for the following
> week.
>
> Last week's Propagation Forecast Bulletin ARLP001 didn't say
> anything about disturbed conditions on the first days of 2005.
> There was a powerful solar flare around 40 minutes into the UTC New
> Year on January 1 (0040z, or 4:40 PM December 31 here on the West
> Coast). The high latitude and planetary A and K indices rose
> dramatically over the following two days. This produced disturbed HF
> conditions. On January 2, the high latitude college A index (in
> Alaska) rose to 64, and it was 44 and 41 over the next two days. The
> planetary A index was up to 33 on January 2, indicating a
> geomagnetic storm.
>
> If you would like to comment or have a tip, email the author at,
> k7ra at arrl.net.
>
> For more information concerning propagation and an explanation of
> the numbers used in this bulletin see the ARRL Technical Information
> Service propagation page at,
> http://www.arrl.org/tis/info/propagation.html.
>
> Sunspot numbers for January 6 through 12 were 14, 22, 34, 28, 40, 25
> and 58 with a mean of 31.6. 10.7 cm flux was 83.2, 83.5, 88.5, 87.5,
> 90.1, 94.2 and 102.1, with a mean of 89.9. Estimated planetary A
> indices were 4, 37, 30, 4, 6, 14 and 30 with a mean of 17.9.
> Estimated mid-latitude A indices were 4, 21, 20, 3, 4, 9 and 18,
> with a mean of 11.3.
> NNNN
> /EX
>