Solar Bulletin, January 2003

• Sudden Ionospheric Disturbance Report

Click image to enlarge. Fig.1. 10 cm Solar Flux and Comparison of Ri (provisional) and Ra Estimates for January 2003 (r=0.958). (Ri Source: http://sidc..oma.be/index.php3) (10cm Source: http://www.drao.nrc.ca/icarus)

Click image to enlarge. Fig.2 Maximum, Mean, and Minimum Ra Values for Each Month from January 2001 to Present.

Recently, several observers have asked to see a comparison of Solar Cycle 23 with Cycle 22. Fig. 3 below presents the smoothed monthly mean values, Rsm, from September 1986 to June 2002.

Click image to enlarge. Fig. 3. Smoothed Sunspot Numbers (Rsm) from September 1986 to July 2002. (AAVSO data)

Graphical comparisons of Cycles 21, 22, and 23 and of Cycles 2,10,13,17,20, and 23 that employ smoothed International numbers (Ri) can be found at http://www.dxlc.com/solar/cyclecomp.html and at http://www.dxlc.com/solar/cyclecomp2.html, respectively. Related text points out that, at least with respect to its development, Cycle 23 is more nearly like Cycles 17 and 20 than like 22. The graphs, prepared by Jan Alvestad of the Norwegian DX-Listener's Club, are presented in color on the referenced website and on the AAVSO website. They are reprinted below with cycle numbers added at the right margins to aid viewers of black and white copy.

Click image to enlarge. Months Since Minimum Fig. 4. Comparison of Cycles 21, 22 and 23. Solid Lines are Smoothed Values. Dotted Lines are Monthly Values. (Source: www.dxlc.com/solar/cyclcomp.html)

Click image to enlarge. Months Since Minimum Fig. 5. Comparison of Cycle 23 with Cycles 2, 13, 10, 17, and 20. (Source: www.dxlc.com/solar/cyclcomp2.html)

Click image to enlarge. Fig. 6. Smoothed Mean Values of the Numbers of Sunspot Groups Reported and the Related Ratios of Spots to Groups from July 2000 to July 2002 (AAVSO data).

Michael Hill, SID Analyst 114 Prospect St Marlborough, MA 01752 USA noatak@aol.com

Observer Code Station(s) monitored A Clerkin A29 NAA A Panzer A83 NAA W Moos A84 FTA ICV DHO M Hill A87 NAA G DiFillipo A93 HWU T Poulos A95 NAA R Battaiola A96 HWU J Wallace A97 NAA M King A99 HWU P Campbell A100 NLK F Steyn A102 NAA NWC L Observatory A107 DHO

The events listed above meet at least one of the following criteria Event reported by two or more observers within +/- 5 minutes Event matched to GOES-8 XRA event to within +/- 15 minutes and event time < 1000 UT Reported by observer with a high quality rating > 8 (scale 1-10)

Solar Events

I didn't get as many reports as I always have in the past this month. I hope the slowing of activity levels doesn't cause some of our observers to lose interest in continuing to submit data. Even when there is less activity it is important to keep the observation base constant so that the data during the peak of the solar cycle matches that of the minimum. We don't want the numbers to be low just because there are less observers submitting data. The more observers that report, even though only reporting a few to ten or fifteen events a month, help to average out any systmeatic errors in the data. If only one observer reports an event, it will not be correlated and therefore not included. So don't give up the ship just yet. We need your data.

I hope you all got to see the new SID/GRB Bulletin. Doug Welch has done a fine job of producing a publication that will be the successor to Cap Hossfields SID Supplement that was a prominent part of this publication. Together with the mailing list that Doug manages for the group he has vastly improved the strength of the SID Monitoring section of the AAVSO Solar Division. Many thanks to Doug for stepping in at this critical moment. I hope the new publication and the mailing list serve you all well with your technical issues to do with SID monitoring and SID equipment as well as GRB hunting.