Sudden Ionospheric Disturbances (SID) Recorded During March 2001

The events listed above meet at least one of the following criteria Reported in at least two observer reports Visually analyzed with definiteness rating = 5 Reported by overseas observers with high definiteness rating

Importance Duration (min) 1- < 19 1 19 – 25 1+ 26-32 2 33-45 2+ 46-85 3 86-125 3+ > 125

Solar Events

March has certainly turned out to be an active month for solar flares. There was a total of 240 X-Ray events measured by the GOES-8 satellite. Of these, 36 were M-Class events and one was a large X-Class event. The most active period was towards the end of the month with the growth of the large sunspot group 9393. This produced a strong series of bursts on the 29th , which was definitely the most active day. There were an astounding 102 measured events reported by observers this month, many of them long duration events. The occurrence of these events is spread out across the month with the most active days being the 7 th, 9 th, 10 th, 20 th, 22 th, 25 th, 27 th and of course the 29th. Interestingly enough, there were 4 days, March 12th to March 15th that had no recorded events at all.

Last month I published a graph of measured daily GOES-8 flare events. This month I have presented the same information but in a different format, as suggested by a former AAVSO SID Analyst, Joseph Lawrence. The plot is a bar graph that stacks the totals of each individual flare class for each day on top of each other. The height of the bar is the daily total. Within the bar, however, the count of each type of flare Class can be determined. The flare categories are, from the bottom up, Class-B, Class-C, Class-M, Class-X. I have done this type of plot for all the data back to July 2000. This will eventually be posted to the web site. Otherwise, the data for each month will be presented here from now on.

• Back to March Solar Bulletin
• Sudden Ionospheric Disturbances Supplement