March 2011

Propagation Summary
The Solar Flux has actually hit the 100 mark in mid February, but had dropped back to 80 by the beginning of March. The Solar Flux should rise to 95 by mid March. The Boulder A index peaked at 25 on the 18th February, dropping back to 5 by the 20th then after peaking at 10 at the beginning of March, it should settle back to the ‘norm’ of 5. The Boulder K Index seems to be the best indicator of SW conditions. If it reaches 5 (like on February 18th) conditions are usually disturbed but, if it drops down to 2, conditions are generally steady. A 24 day forecast can be found at: http://www.wm7d.net/hamradio/solar/27d_forecast.shtml
The Solar flux trend charts at www.solarcycle24.com/flares.htm show that the dip in progress during mid 2010 has recovered but numbers are still well below predicted levels. The Solar flux would need to be averaging at around 110 to reach it’s predicted peak in the first quarter of 2013. There were 260 spotless days in 2009 (70%) compared with just 51 in 2010 (14%).

First X-flare of the New Solar Cycle Earth-orbiting satellites have detected the strongest solar flare in more than four years. At 0156 UT on Feb. 15th, giant sunspot 1158 unleashed an X2-class eruption. X-flares are the strongest type of x-ray flare, and this is the first such eruption of new Solar Cycle 24. The explosion that produced the flare also sent a solar tsunami rippling through the sun's atmosphere and, more importantly, hurled a coronal mass ejection toward Earth. This is likely to have caused the disturbance on February 18th. A Radio Blackout Indicator can be found at www.solarcycle24.com as well as pictures and video of solar activity.

Sunspot Data (Royal Greenwich Observatory)
Sunspots appear as dark spots on the surface of the Sun. They typically last for several days, although very large ones may live for several weeks. Sunspots are magnetic regions on the Sun with magnetic field strengths thousands of times stronger than the Earth's magnetic field. Sunspots usually come in groups with two sets of spots. One set will have positive or north magnetic field while the other set will have negative or south magnetic field. The field is strongest in the darker parts of the sunspots - the umbra. The field is weaker and more horizontal in the lighter part - the penumbra.
The Royal Greenwich Observatory (RGO) compiled sunspot observations from a small network of observatories to produce a data set of daily observations starting in May of 1874. The observatory concluded this data set in 1976 after the US Air Force (USAF) started compiling data from its own Solar Optical Observing Network (SOON). This work was continued with the help of the US National Oceanic and Atmospheric Administration (NOAA) with much of the same information being compiled through to the present. Unfortunately, the more recent data is given in a different format from the original and there are definite changes in the reported parameters from the different sources. In an effort to append the RGO data with the more recent data I have reformatted the USAF and NOAA data to conform to the older RGO data format. The entire data set is available below as ASCII text files containing records for individual years. Each file consists of records with information on individual sunspot groups for each day that spots were observed. The series of data files from 1874-2004 are also available in a single 5.1 Mb ZIP file at: http://solarscience.msfc.nasa.gov/greenwch/RGO_NOAA1874_2004.zip .

Solar Activity MonitorA Solar Activity Monitor can be found at: http://www.n3kl.org/sun/status.html . If you have a website, you can also display the monitor on your web pages.

Acknowledgements to Mike Terry and Ken Fletcher for articles and updates.