ZCZC AP40
QST de W1AW
Propagation Forecast Bulletin 40 ARLP040
From Tad Cook, K7RA
Seattle, WA October 3, 2003
To all radio amateurs
SB PROP ARL ARLP040
ARLP040 Propagation de K7RA
This has been a good week for HF propagation. Not only have we moved into fall with its associated good HF propagation around the equinox, but this week also saw rising sunspot and solar flux values coupled with quieter geomagnetic conditions.
Average daily sunspot numbers rose from the week previous by 33 points to 125. The average daily solar flux for the week was nearly 15 points higher at 133.6. Excepting the first day of the reporting week, when the planetary A index was 28, these numbers settled down to average only 12--nearly 15 points lower than the previous week. The quietest days were Sunday through Tuesday, September 28-30. Even at high latitudes, conditions were stable, with Alaska's college A index at four on two of the days.
We are now within a solar wind, but it is moderate and probably won't cause any upset, at least for the next few days. Predicted planetary A index for Friday through Sunday, October 3-5, is 12, 10 and 10. On Monday it could rise to 15, then higher numbers are predicted, a planetary A index of 20 for October 7-8. Solar flux is expected around 120-125 over the next week.
Let's look at the numbers for the third quarter of 2003, which just ended: Average daily sunspots for July 1 through September 30 were 110.2, slightly higher than the previous quarter. From the third quarter of 2002 through the current quarter the average daily sunspot numbers were 193.5, 152.7, 120.3, 107.3 and 110.2. That reflects a definite downward trend with levels relatively unchanged from the last quarter to the current one.
Average daily solar flux for the same five quarters were 178.1, 164.2, 134.3, 124.2 and 120.8. No doubt about a smooth downward slide there. Propagation this fall will surely not be as good as last year's as these numbers continue.
Over the past three months, July through September, average monthly sunspot numbers were 132.8, 114.3 and 82.6. Average solar flux numbers for those same months were 127.1, 122.1 and 112.2.
Grim news emerged recently concerning the NOAA Space Environment Center in Colorado, where most of the data for these bulletins originates. I suspect due to some misunderstanding about their work, the Senate Appropriations Committee wants to eliminate the Space Environment Center's budget for fiscal year 2004, which officially began October 1. The Senate Appropriations Committee said in a report that NOAA's work should only be terrestrial and not extend to space, so it's proposing to cut all funding for the SEC. The House appropriations bill proposes cutting funding by 40 percent, even in the wake of severe cuts during the fiscal year just ended.
The funny thing about the Senate report is that all of the effects of solar flares and sunspots that concern us are here on Earth. Claiming that NOAA should ignore the sun because it is in space seems silly, since the same standard doesn't apply to NOAA's conventional weather forecasting. The SEC is a small part of NOAA, with an annual budget of just 8 million dollars.
There's a story on this subject on the ARRL Web site (see "Space Environment Center Funding in Jeopardy"). The Seattle Post-Intelligencer ran a story in its October 2 editions, and there's an item on the September 20 SpaceWeather.com Web page, available in the archive for that date.
I've contacted my representatives in the Senate and House and found that, as expected, staff members really had no idea what the obscure sounding Space Environment Center does. The only hope is that when the House and Senate committees work out that portion of the budget, funding for the SEC will somehow be preserved. You might contact your representatives to inquire about this. Members of the Senate Appropriations Committee are listed on the committee's Web site.
For more information on propagation and an explanation of the numbers used in this bulletin see the Propagation page on the ARRL Web site.
Sunspot numbers for September 25 through October 1 were 122, 127, 137, 139, 108, 116 and 126, with a mean of 125. The 10.7-cm flux was 132.6, 131.1, 129.7, 137, 135.1, 133 and 136.8, with a mean of 133.6. Estimated planetary A indices were 28, 17, 9, 6, 7, 7 and 10, with a mean of 12.