November '09

Propagation Forecast
Sunspot activity has once again died down, apart from a minor sunspot on 20 October which has made little difference to the calm conditions which will remain until at least mid November. The Solar Flux will remain at a maximum of 72, and is likely to drop as low as 69, returning to 72 by the 15th. The Boulder A and K indicies will also remain at a steady 5 and 2 repectively during early November. Following speculation new sunspot activity, there has not been any major sunspot activity so far. (From http://www.wm7d.net/hamradio/solar/27d_forecast.shtml )

On 24 October, the NOAA 45 day forecast predicts nothing significant, even up to early December 09: ( www.swpc.noaa.gov/ftpdir/forecasts/45DF/102345DF.txt ) Most long term estimates show a steady rise in sunspot activity which peaks in late 2012 but the actual smoothed sunspot estimates show current figures to be lower than estimated. (http://solarcycle24.com/ )

The Boulder K Index seems to be the best indicator of HF reception conditions. A reading of 3 or under usually indicates calm conditions but 5 or over usually means a noticeable disturbance on the bands.
( http://www.swpc.noaa.gov/alerts/k-index.html )

The K7RA Update
“A tiny Solar Cycle 24 sunspot group -- numbered 1028 -- emerged briefly on Tuesday, October 20, and then was gone. This is another brief phantom sunspot, teasing us with hints of the expected increase in activity that never seems to manifest. Of course, the silver lining in the low solar activity is low geomagnetic activity. While folks in Alaska miss dramatic aurora, HF hams in the northern latitudes can enjoy the bands without all the disruption that comes with geomagnetic storms.

Sunspot numbers for October 15-21 were 0, 0, 0, 0, 0, 11 and 0 with a mean of 1.6. The 10.7 cm flux was 70.4, 69.6, 70.7, 70.1, 70.9, 71 and 71.3 with a mean of 70.6. The estimated planetary A indices were 4, 4, 2, 1, 1, 1 and 1 with a mean of 2. The estimated mid-latitude A indices were 3, 3, 0, 0, 1, 0 and 1 with a mean of 1.1. Franta Janda, OK1HH, of the Czech Propagation Interest Group expects a bit higher activity, with quiet conditions for October 23 and unsettled to active geomagnetic conditions for October 24-25.

A couple of coronal holes are spewing enough plasma to activate some aurora, but remember that most of the photos you see of beautiful displays in the sky are actually very long exposures taken from a rock-steady tripod mount; many times, the unaided eye cannot perceive the more dramatic details. As a result of solar wind from coronal holes, geomagnetic indices rose yesterday, on Thursday, with planetary A index at 14, mid-latitude A index as measured in Virginia at 12 and the College A index at Fairbanks, Alaska way up to 25.

The College A index has been quiet for a long time; the last time the index was nearly this high was on August 30, 2009 at 24. Prior College A index readings higher than Thursday's were July 22, 2009 at 27, February 4, 2009 at 36, December 6, 2008 at 26 and November 8, 2008 at 30.”
(From Tad Cooke: http://www.arrl.org/news/stories/2009/10/23/11162/?nc=1 )

Forecast Of Next Sunspot Cycle
In 2006, scientists predicted that the next cycle, known as Cycle 24, will produce sunspots across an area slightly larger than 2.5 percent of the visible surface of the Sun. The cycle is projected to reach its peak about 2012, one year later than indicated by alternative forecasting methods that rely on statistics.
By analyzing recent solar cycles, the scientists also hope to forecast sunspot activity two solar cycles, or 22 years, into the future. The researchers expect that predicting the Sun's cycles years in advance will lead to more accurate plans for solar storms, which can slow satellite orbits, disrupt communications, and bring down power systems. The team has verified the information by using the relatively new technique of helioseismology, based in part on observations from NASA instruments. This technique tracks sound waves reverberating inside the Sun to reveal details about the interior, much as a doctor might use ultrasound to see inside a patient.
The programme’s director, Paul Bellaire said, "Important discoveries are being made using helioseismology. Through this technique, we can image even the far side of the Sun."
Links to this months articles can be found at http://www.jameswelsh.org.uk/.

Thanks to Ken Fletcher and Mike Terry for updates during 2009. The next Propagation report will be in January 2010.