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 6, 2012   
   To all radio amateurs    
      
   SB PROP ARL ARLP001   
   ARLP001 Propagation de K7RA   
      
   Reports of good conditions continue, although sunspot activity   
   declined a bit.  Average daily sunspot numbers for December 29   
   through January 4 declined nearly 20 points (when compared to the   
   previous seven days) to 88.1.  Average daily solar flux was off 6.4   
   points to 143.1.   
      
   88.1 is the lowest reported weekly sunspot number average since   
   Propagation Forecast Bulletin ARLP035 from 18 weeks ago.   
      
   As expected, last week's report of 80.1 as the average daily sunspot   
   number for all of 2011 was correct.  The additional sunspot numbers   
   from December 30-31 did not change it, but we just had to verify.   
      
   In a preview for this bulletin in Thursday's ARRL Letter, I   
   indicated a problem with the planetary A index numbers we are   
   getting from NOAA.  I made an inquiry, and heard from Mike Husler of   
   NOAA/SWPC.  NOAA is no longer getting planetary A and K index data   
   from the USAF, but is now doing their own estimates. But their   
   estimates seemed to be too low, so they have changed their method   
   for calculating planetary A and K indices.   
      
   Mike Husler wrote, "A comparison of our new real-time Kp estimate   
   with the official values for October-December showed that we were   
   tending to estimate too low. In order to improve the situation we   
   reran the fits between stations' Ks (as they would be derived using   
   our real-time algorithm) and official Kp to get an updated table of   
   conversion coefficients. The new values have been deployed as of 4   
   January 2012 at 1500Z.   
      
   "For 10/19/2011-12/15/2011 we found the following improvement in   
   performance of the estimate compared to the official values: Kp Mean   
   absolute error decreases from 0.44 to 0.24.  Average bias improves   
   from -0.41 to 0.00   
      
   "Ap Mean absolute error decreases from 1.93 to 0.98.  Average bias   
   improves from -1.69 to -0.34.   
      
   "You should generally see somewhat higher Kp and Ap values than you   
   have been seeing previously. The values from 10/1/2011 forward are   
   NOAA Kp values with the correction stated above and the values prior   
   to that are from the USAF Kp."   
      
   They are currently going back and correcting data for the last few   
   months of 2011. I do not know what he meant by ''official values,''   
   but I suspect that since the Ap and Kp values are called estimates,   
   that there is some other longer term method for determining   
   "official values."   
      
   Mike also wrote, "Here is a web page for general information about   
   the Kp and Ap indices from the official source:   
      
   "http://www-app3.gfz-potsdam.de/kp_index/index.html   
      
   "Here is a link to the data files that are updated twice per month.   
   I recommend people use these data if they need something that is for   
   previous months:   
      
   "ftp://ftp.gfz-potsdam.de/pub/home/obs/kp-ap/"   
      
   A new solar cycle prediction was released on January 3, revised   
   slightly lower from the prediction released less than three weeks   
   before, on December 16.   
      
   The key phrase from the December 16 prediction: "We find a starting   
   time of October 2008 with minimum occurring in December 2008 and   
   maximum of about 99 in February of 2013."  This was changed in the   
   January 3 prediction to: "We find a starting time of October 2008   
   with minimum occurring in November 2008 and maximum of about 96 in   
   February of 2013."   
      
   The latest version is at:   
   http://solarscience.msfc.nasa.gov/predict.shtml .   
      
   The Washington Post recently ran a blog post on space weather events   
   of 2011.  Read it at   
   washingtonpost.com/blogs/capital-weather-gang/post/.  Look for the   
   top-space-weather-and-astronomy-events-of-2011/2012/01/05/gIQAMMzqcP_blog.html   
   link.   
      
   We received 6 meter reports from Jon Jones, N0JK.  On December 30 he   
   wrote: "Great Es on 6M yesterday 12/29.  Open most of the afternoon   
   and evening for many parts of the USA. And Es links from W4, W5 and   
   W8 to E51 and ZL. K5N was a Grid DXpedition active yesterday from   
   the line from two rare grids, DM90/DL99. The Es allowed them to give   
   many ops two really rare new grids. I logged them at 0403 UTC 12/30   
   on my indoor dipole. They were in to my location only about 7   
   minutes."   
      
   On January 5, Jon wrote: "The 6 Meter band really came alive last   
   week. Major long lasting Es openings on Dec. 30, 31 and Jan. 1. New   
   Years Eve worked NP4A FK68 on double hop Es. Jan. 1 strong short Es   
   to ND, MN, WY, etc. Noted spots by stations in W4, W5 to VK, ZL on   
   Es links New Years Eve."   
      
   Thanks, Jon.   
      
   If you would like to make a comment or have a tip for our readers,   
   email the author at, k7ra@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 29 through January 4 were 105, 104, 68,   
   61, 83, 95, and 101, with a mean of 88.1. 10.7 cm flux was 147.1,   
   141.1, 132.9, 130, 134.7, 134.6, and 136.2, with a mean of 136.7.   
   Estimated planetary A indices were 7, 6, 4, 4, 5, 7, and 3, with a   
   mean of 5.1. Estimated mid-latitude A indices were 7, 5, 5, 4, 4, 9,   
   and 3, with a mean of 5.3.   
   NNNN   
   /EX   
      
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