November 2011

Propagation Summary
The Solar flux has peaked at 140 on September 27-28^th but there is again a downward trend, which will see a drop to 105 by November 7^th. The only noticeable disturbance on propagation conditions was on October 5-6, with the Boulder A index peaking at 18, and the K Index peaking at 5. The general trend for sunspot activity is up, although certainly not to the predicted levels. Daily updates can be found at http://www.wm7d.net/hamradio/solar/27d_forecast.shtml

Historical Solar charts going back to 1950 are available at http://www.solen.info/solar/history/

Implications for Long Term Space Climate Change

“The recent solar minimum was the longest and deepest of the space age, with the lowest average sunspot numbers for nearly a century. The Sun appears to be exiting a grand solar maximum (GSM) of activity which has persisted throughout the space age, and is headed into a significantly quieter period. Indeed, initial observations of solar cycle 24 (SC24) continue to show a relatively low heliospheric magnetic field strength and sunspot number (R), despite the average latitude of sunspots and the inclination of the heliospheric current sheet showing the rise to solar maximum is well underway. We extrapolate the available SC24 observations forward in time by assuming R will continue to follow a similar form to previous cycles, despite the end of the GSM, and predict a very weak cycle 24, with R peaking at ∼65–75 around the middle/end of 2012. Similarly, we estimate the heliospheric magnetic field strength will peak around 6nT. We estimate that average galactic cosmic ray fluxes above 1GV rigidity will be ∼10% higher in SC24 than SC23 and that the probability of a large SEP event during this cycle is 0.8, compared to 0.5 for SC23. Comparison of the SC24 R estimates with previous ends of GSMs inferred from 9300 years of cosmogenic isotope data places the current evolution of the Sun and heliosphere in the lowest 5% of cases, suggesting Maunder Minimum conditions are likely within the next 40 years.” From: http://www.agu.org/pubs/crossref/2011/2011GL049328.shtml

Solar Flare Alerts by Text or Phone

Real time solar activity alerts to your mobile phone or landline phone can be set up online at http://spaceweathertext.com (text) and http://spaceweatherphone.com (voice).

Future Sunspot Cycle Predictions

Sunspot Cycles are Difficult to Accurately Predict. Solar physicists believe the speed of a massive circulating current of hot plasma within the Sun predicts the amplitudes of sunspot Cycles approximately twenty years into the future. In the years prior to 2006 that speed had become lower than ever before. Based on the plasma-speed/future-cycle-amplitude theory, a team led by physicist Mausumi Dikpata of the National Centre for Atmospheric Research predicted Cycle 24 would be intense. NASA solar physicist David Hathaway agreed, but predicted Solar Cycle 25 will be very weak.

VHF Propagation Software

A new VHF propagation gadget is available from SV2AGW. There are two Windows Vista Side Bar gadgets, for Europe and North America. They display Aurora and Sporadic-e propagation using the dxrobot images. George Rossopoulos, SV2AGW has also produced software for AX.25 Packet / APRS, which can be downloaded from his website. http://www.sv2agw.com/downloads/default.htm (Via Mike Terry)

Thanks to Mike Terry and Ken Fletcher for regular updates. The next Propagation report will be in January. Links to these articles and more are available at http://www.jameswelsh.org.uk