The K7VVV Solar Update

SEATTLE, WA, Apr 5, 2002--Average daily solar flux rose last week by 27 points, and average sunspot numbers was up by more than 9 points. We've had active geomagnetic conditions this week caused by a stream of high-speed solar wind. This has yielded auroral displays at high latitudes. Saturday through Wednesday were very active, and the planetary K index was four during several three-hour periods.

Solar flux for the short term is expected to peak around 215 for Friday and Saturday, then drift below 200 after Tuesday. Geomagnetic conditions could become slightly active or unsettled on Saturday.

Currently there is a large complex of sunspots crossing the visible solar disk. A helioseismic image also shows a pair of large sunspots on the sun's far side.

Kenzo Nose, JA3EGE wrote about some great recent 6-meter openings he observed in Japan. On March 17 from 2035 to 2300 UTC he worked stations in the South Pacific, and long path into Europe and the Caribbean. He said it was the most unusual propagation he has observed in 30 years. He worked 9H1, EH3, IS0, IT9, EH6, FJ5, FM5, FG5, PJ2, YV5 and P49. You can reach Kenzo via email at ja3ege@arrl.net.

The beginning of April marked the end of the first quarter of 2002 so it is time to look at some of the numbers.

Average daily sunspot numbers for the last five quarters, from January 1, 2001, to March 31, 2002, were 147.3, 164.8, 170.4, 198.1 and 178.3. Average daily solar flux for the same five periods was 164.4, 166.7, 175.5, 219.1 and 203.9. Both solar flux and sunspot numbers were higher this past quarter than the first three quarters of 2001, but lower than the last quarter of last year, which had a lot of activity.

Average sunspot numbers for the past five months, November through March, were 178.6, 217.5, 189, 194.5 and 153.1. Average daily solar flux for the same five months was 215.8, 236.5, 227.3, 205, and 179.5.

We can definitely see the peak that occurred around December, and that January of this year had more activity than November of last year. But March solar flux and sunspots were definitely down.

Sunspot numbers for March 28 through April 3 were 144, 189, 171, 133, 189, 262 and 162, with a mean of 178.6. The 10.7-cm flux was 176.2, 181.3, 188.7, 204.4, 207, 206 and 209.4, with a mean of 196.1. Estimated planetary A indices were 6, 7, 17, 14, 16, 15 and 13 with a mean of 12.6.

Amateur solar observer Tad Cook, K7VVV Seattle, Washington, provides this weekly report on solar conditions and propagation. This report also is available via W1AW every Friday, and an abbreviated version also appears in The ARRL Letter. Readers may contact the author via k7vvv@arrl.net.

Previous: Changing of the Guard Announced at Hurricane Watch Net

Next: Deception Island