SB PROP @ ARL $ARLP011 ARLP011 Propagation de K7RA ZCZC AP11 QST de W1AW Propagation Forecast Bulletin 11 ARLP011 >From Tad Cook, K7RA Seattle, WA March 16, 2012 To all radio amateurs
SB PROP ARL ARLP011 ARLP011 Propagation de K7RA Average daily sunspot numbers over the past reporting week (March 8-14) were 88.3, a rise of nearly 19 points. Average daily solar flux rose over 12 points to 134.2. Four new sunspots emerged, the first was sunspot group 1432 on March 9 (misidentified as 1421 in yesterday's ARRL Letter), which began with a relative area of 90, and in the following days went to 80, 50, 80, 70, 60 and 100. Two sunspot groups, numbered 1433 and 1434 appeared on March 11, with a combined relative size (in millionths of a solar hemisphere) of 240, then 130, 140, 150 and 150. Finally on March 15, a new sunspot group 1435 emerged, with a relative size of 30. The daily sunspot number on this day rose to 85. The sunspot number peaked on March 11 at 103, and the solar flux on March 10 at 148.9 and again on March 13 at 140.7. The outlook for the next few days has solar flux at 110 on March 16, 105 on March 17-21, 100 on March 22, 105 on March 23-27, 110, 115 and 125 on March 28-30, and 130 on March 31 through April 5. There was a great deal of geomagnetic activity on March 9 with a planetary A index at 68, and again on March 12 with a planetary A index of 28. An M-class x-ray flare occurred on March 15 at 0752 UTC, and if you catch it soon enough, you can see the resulting x-ray flux on the GOES monitor at, http://www.swpc.noaa.gov/rt_plots/xray_5mBL.html. The predicted planetary A index for March 16-17 are 18 and 10, then 5 for March 18-27, 10 on March 28, 8 on March 29-31, 5 on April 1-2, 8 on April 3-4 and 5 on April 5-9. The Vernal Equinox will occur at 0514 UTC on March 20. The shift to Spring in the Northern Hemisphere and Autumn in the Southern Hemisphere generally signals favorable conditions for HF propagation. Thanks to Howard Lester, N7SO, who sent in a photo of a backyard telescope in Brooklyn, New York owned by Alan Friedman and operated among city lights: http://www.avertedimagination.com/img_pages/little_big_man.html. Howard also sent this solar image from March 11 using the same telescope, with appropriate filters, of course: http://www.avertedimagination.com/img_pages/x-rated2.html. A detail of region 1429: http://www.avertedimagination.com/img_pages/x-rated.html. NASA posted a nice image plus a video of sunspot region 1429. See it at, http://www.nasa.gov/mission_pages/sunearth/news/flare-20120313.html. Scott Woelm, WX0V of Fridley, Minnesota wrote: "Bob Conzemius, KB0ZXT, of Grand Rapids, Minnesota has some rather spectacular time-lapse video of aurora displays. These can be accessed on his youtube site at http://www.youtube.com/user/TornadoBob1."; If you would like to make a comment or have a tip for our readers, email the author at, k...@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 March 8 through 14 were 86, 96, 89, 103, 89, 80, and 75, with a mean of 88.3. 10.7 cm flux was 139.5, 145.5, 148.9, 131.2, 114.9, 140.7, and 118.8, with a mean of 134.2. Estimated planetary A indices were 24, 68, 18, 8, 28, 10, and 8, with a mean of 23.4. Estimated mid-latitude A indices were 21, 57, 17, 10, 28, 10, and 6, with a mean of 21.3. NNNN /EX ----------------------------------------------------------- To unsubscribe or subscribe to this list. Please send a message to imail...@njdxa.org In the message body put either unsubscribe dx-news or subscribe dx-news This is the DX-NEWS reflector sponsored by the NJDXA http://njdxa.org -----------------------------------------------------------
