[KCDXC] Fw: ARLP012 Propagation de K7VVV

[Steve Lufcy]

Sent: Friday, March 22, 2002 9:03 PM
Subject: Fw: ARLP012 Propagation de K7VVV


> 
> > SB PROP @ ARL $ARLP012
> > ARLP012 Propagation de K7VVV
> > 
> > ZCZC AP12
> > QST de W1AW  
> > Propagation Forecast Bulletin 12  ARLP012
> > From Tad Cook, K7VVV
> > Seattle, WA  March 22, 2002
> > To all radio amateurs 
> > 
> > SB PROP ARL ARLP012
> > ARLP012 Propagation de K7VVV
> > 
> > Average daily solar flux and sunspot numbers for the past week were
> > almost identical to the previous week. Average sunspot numbers were
> > less than two points lower, and average solar flux rose less than
> > one point. Geomagnetic activity was essentially the same, with the
> > average estimated planetary A index less than a point higher this
> > week.
> > 
> > On March 19 the interplanetary magnetic field moved south, leaving
> > the earth vulnerable to solar wind. The planetary K index rose to 5
> > over two 3-hour periods, but during other periods through the day K
> > indices were very low. This resulted in a planetary A index for that
> > day of only 17, which indicates unsettled to active conditions. If
> > the K index were 5 through all eight 3-hour periods, the A index
> > would be around 50, indicating a geomagnetic storm. An A index of 17
> > for the day corresponds to an average K index of a little above 3.
> > 
> > The K index is a quasi-logarithmic index over three hours of
> > geomagnetic activity from a particular observatory. For instance, on
> > WWV at 18 minutes after the hour (you can also hear this report
> > anytime by calling 303-497-3235) you would hear the Boulder K index
> > from Colorado, although they have switched to a new reporting scale
> > that uses the mid-latitude K index.
> > 
> > The planetary K-index, or Kp, is a mean of the values taken from
> > thirteen observatories that are between 44 and 60 degrees northern
> > or southern latitude. The planetary A index, or Ap, is derived from
> > the average of the Kp values for the day. If the Kp average is 1,
> > this corresponds to an Ap for the day of 4. Kp of 2 equals Ap of 7,
> > Kp of 3 equals Ap of 15, Kp of 4 equals Ap of 27, Kp of 5 equals Ap
> > of 48, Kp of 6 equals Ap of 80, and the scale continues up to a Kp
> > of 9. The Boulder, or any other local A index is derived the same
> > way. For a thorough explanation of the scale see,
> > http://www.ngdc.noaa.gov/stp/GEOMAG/kp_ap.html and
> > http://www.sec.noaa.gov/info/Kindex.html .
> > 
> > At 1330z on March 20 a coronal mass ejection that left the sun on
> > March 18 near sunspot 9866 passed earth. It triggered some
> > geomagnetic activity, but only for a short period when both the
> > planetary K index reached 4 and the mid-latitude K index reached 5.
> > The rest of the day had very low K index numbers.
> > 
> > N4KG sent a note about the equinox and the effect on propagation.
> > He writes ''To my mind, the major benefit of the equinox period is
> > improved polar path propagation on the high bands (17-10 meters)
> > from three weeks before to three weeks after the equinox.'' He said
> > that 9N7RB is coming in during North America's local morning and
> > evening hours on 10 meters, shortly after sunrise and after sunset,
> > wrapping around the poles from both sides.
> > 
> > K0ZN is wondering when the next solar minimum will be. According to
> > a recent NOAA Preliminary Report and Forecast of Geophysical Data,
> > their prediction shows it to be some time between September 2006 and
> > April 2007. Still a ways off, and right now we are enjoying the peak
> > of the current cycle. You can read these NOAA reports at,
> > http://www.sec.noaa.gov/weekly/ , and the one showing the latest
> > solar cycle projection is the March 5 issue. You can also see some
> > nice historic charts of this and previous solar cycles on WM7D's web
> > site at, http://www.wm7d.net/hamradio/solar/index.epl ,
> > http://www.wm7d.net/hamradio/solar/past_cycle.shtml and
> > http://www.wm7d.net/hamradio/solar/historical.shtml .
> > 
> > KN9P and several others wrote in asking about the new unfamiliar
> > propagation reports on WWV. NOAA is using some new scales. An
> > article about this is at,
> > http://www.sec.noaa.gov/NOAAscales/EosNewScales.html and the scales
> > are explained at http://www.sec.noaa.gov/NOAAscales/ .
> > 
> > The latest forecast has unsettled conditions for Friday, with a
> > planetary A index around 15. Solar flux for the next week and a half
> > is expected to be a little lower than the past two weeks, between
> > 165 and 170.
> > 
> > Sunspot numbers for March 14 through 20 were 162, 134, 124, 124,
> > 136, 119 and 141 with a mean of 134.3. 10.7 cm flux was 180.7,
> > 175.9, 184.6, 184.4, 178.1, 174.8 and 187.8, with a mean of 180.9,
> > and estimated planetary A indices were 4, 6, 5, 4, 12, 17 and 7 with
> > a mean of 7.9.
> > NNNN
> > /EX
> > 
> > 
> > 
> 
>