Propagation January 2010

Propagation Forecast
January is likely to remain fairly calm with the Boulder A index remaining at 5 and the K index at 2 throughout the month. The Solar flux will start at 80 and should drop to 76 by the end of the month. The http://www.wm7d.net/hamradio/solar/27d_forecast.shtml Maximum Useable frequencies Western Europe for daylight hours in January are 6-7 MHz. http://hfradio.org/fot_7.html

2009 has seen a total of 209 days of zero sunspot activity (71%), according to Spaceweather.com and is estimated to be the 5th most spotless year since 1849. http://anhonestclimatedebate.wordpress.com/category/sunspots/

Solar Cycle Prediction
A number of techniques are used to predict the amplitude of a cycle during the time near and before sunspot minimum. Relationships have been found between the size of the next cycle maximum and the length of the previous cycle, the level of activity at sunspot minimum, and the size of the previous cycle.

Predicting the behaviour of a sunspot cycle is fairly reliable once the cycle is well underway (about 3 years after the minimum in sunspot number occurs. Prior to that time the predictions are less reliable but nonetheless equally as important. Planning for satellite orbits and space missions often require knowledge of solar activity levels years in advance. A number of techniques are used to predict the amplitude of a cycle during the time near and before sunspot minimum. Relationships have been found between the size of the next cycle maximum and the length of the previous cycle, the level of activity at sunspot minimum, and the size of the previous cycle.

Among the most reliable techniques are those that use the measurements of changes in the Earth's magnetic field at, and before, sunspot minimum. These changes in the Earth's magnetic field are known to be caused by solar storms but the precise connections between them and future solar activity levels is still uncertain.

Of these "geomagnetic precursor" techniques three stand out. The earliest is from Ohl and Ohl [Solar-Terrestrial Predictions Proceedings, Vol. II. 258 (1979)] They found that the value of the geomagnetic A index at its minimum was related to the sunspot number during the ensuing maximum. The primary disadvantage of this technique is that the minimum in the geomagnetic A index often occurs slightly after sunspot minimum so the prediction isn't available until the sunspot cycle has started.

An alternative method is due to a process suggested by Joan Feynman. She separates the geomagnetic A index into two components: one in phase with and proportional to the sunspot number, the other component is then the remaining signal. This remaining signal faithfully represents the sunspot numbers several years in advance. The maximum in this signal occurs near sunspot minimum and is proportional to the sunspot number during the following maximum. This method does allow for a prediction of the next sunspot maximum at the time of sunspot minimum.

A third method is due to Richard Thompson [Solar Physics 148, 383 (1993)]. He found a relationship between the number of days during a sunspot cycle in which the geomagnetic field was "disturbed" and the amplitude of the next sunspot maximum. His method has the advantage of giving a prediction for the size of the next sunspot maximum well before sunspot minimum.
From: http://solarscience.msfc.nasa.gov/predict.shtml 8 December 2009

Sunspot Plotter
Here is a web page where you can go to a specific date and get sunspot data to compare reception conditions with the Solar conditions at the time.
http://spaceweather.com/glossary/sunspotplotter.htm

Thanks to Mike Terry and Ken Fletcher for regular updates