The K7VVV Solar Update
SEATTLE, WA, Jul 28, 2000--Solar flux and sunspot numbers were down only slightly this week from last. Last week's average sunspot numbers were up over 40 points from the previous week, and this week's are down less than seven. But the big news this week should be the big peak in sunspot numbers on Thursday, July 20, when it reached 401. This is a rare, high number in any solar cycle, and the biggest so far in cycle 23.
A cursory examination of the data shows that the sunspot number has not been this high since August 23, 1991, when it was 478. Sunspot numbers over 400 suggest that we may be nearing the cycle peak. The latest projection the author has seen for cycle peak is from the July 4 Preliminary Report and Forecast of Solar Geophysical Data from the NOAA Space Environment Center. It shows smoothed monthly solar flux peaking in August or September, but smoothed sunspot numbers peaking around next January or February.
The latest short term projections show some rough weather ahead for the weekend, with the planetary A index for Friday through Tuesday at 30, 25, 12, 12 and 10. Projected solar flux for those same five days is 160, 155, 155, 150 and 145. Solar flux should rise above 200 by August 4, then reach 230 on August 8-14, and peak around 235 on August 15-16.
WF7M wrote to ask about geomagnetic indices for Alaska. This is identified as the College index. These values are generally higher than the mid-latitude or planetary indices.
Sunspot numbers for July 20 through 26 were 401, 325, 290, 276, 215, 232 and 214 with a mean of 279. The 10.7 cm flux was 252.9, 250.9, 251, 217.3, 224.8, 201.8 and 174.6, with a mean of 224.8. The estimated planetary A indices were 43, 9, 18, 20, 8, 7 and 20, with a mean of 17.9.
Carl Luetzelschwab, K9LA, has generously agreed to prepare next week's bulletin while I am on vacation.
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.
Page last modified: 10:28 AM, 28 Jul 2000 ET
Page author: awextra@arrl.org
Copyright © 2000, American Radio Relay League, Inc. All Rights Reserved.
![Previous (earlier) Story](/images/sty-down.gif "ARRL Volunteers Find, Fix "The Ditter""){kind=small}
Previous: ARRL Volunteers Find, Fix "The Ditter"![Next (later) Story](/images/sty-up.gif "ARRL Volunteers Find, Fix "The Ditter""){kind=small}
Next: ARRL Volunteers Find, Fix "The Ditter"
