 |
 |
|
|
|
|
|
|
||||||||||||||||||
|
|
|||||||||||||||||||
|
|
|||||||||||||||||||
|
|||||
|
|
![Previous (earlier) Story](/images/sty-down.gif ""It Seems to Us . . ." Nine Decades"){kind=small} Previous: "It Seems to Us . . ." Nine Decades |  Next: Surfin': Hams on Wheels |
SEATTLE, WA, Jan 2, 2004--This is the first "Solar Update" for 2004--time to review averages from 2003 and compare them to previous years.
From the third quarter of 2002 through the last quarter of 2003, the average daily sunspot numbers were 193.5, 152.7, 120.3, 107.3, 110.2 and 99.2. Average daily solar flux for the same six quarters were 178.1, 164.2, 134.3, 124.2, 120.8 and 137.4.
Average daily sunspot numbers for 1997 through 2003 were 30.7, 88.7, 136.3, 173, 170.3, 176.6 and 109.2. Average daily solar flux for the same seven years was 81, 117.9, 153.7, 179.6, 181.6, 179.5 and 129.2. By averaging the daily numbers on an annual basis, we certainly can see a decline in the solar cycle over the past few years.
Over the next week, expect solar flux numbers between 120 and 125. A geomagnetic forecast for January 1 predicted planetary A index values for January 2-8 of 20, 15, 35, 30, 35, 35 and 25. With the exception of this Saturday, January 3, those numbers portend rough conditions with geomagnetic storms--especially in those cases where the A index is above 30. This should be the result of a big blast of solar wind beginning on Sunday, January 4.
Remember that the long winter nights are great for 160, 80, 60, 40 and 30 meters. The typically higher summertime noise is long gone, and long hours of darkness are great for the lower frequencies--at least when there isn't a major geomagnetic storm.
In the past we've featured links to US and Canadian sites that offer information on space weather, but you might want to check out The Australian Space Weather Agency page. Click on "Space Weather" to view an update on geomagnetic indices and HF fadeout warnings. Select "HF Systems," and then look to the vertical field on the left and click on links to ionospheric maps for Australasia, Asia, North America, North Atlantic and Europe.
If you've ever been interested in plotting solar flux and sunspot numbers, in the past we've mentioned the free Solar Data Plotting Utility, by Scott Craig, WA4TTK, which runs in Windows. The Solar Data Plotting Utility is available from Craig's Web site. The page indicates that an MS-DOS version of the program is available too. The Windows version specified Windows 95 or Windows NT4, but I've used it with Windows 98, Windows 98 SE, Windows 2000 Pro and Windows XP with no problems.
On New Year's Eve, I uploaded 15 years of data for his program to his Web site. This is nice if you haven't been running this program before and updating the data file. The software can pull the data out of the bottom of this weekly bulletin and add it to the existing data file. It can also grab the data via FTP from the ARRL. If you have any gaps or are starting new with this program, the complete data file through December 31, 2003, can be quite handy. Download it if you need it, and you can add to it weekly or daily from now on.
For more information about propagation and an explanation of the numbers used in this bulletin see the Propagation page on the ARRL Web site.
Sunspot numbers for December 25 through 31 were 58, 65, 47, 47, 56, 15 and 25, with a mean of 44.7. The 10.7 cm flux was 139.1, 137.2, 161.5, 119, 114.5, 107.7 and 105.6, with a mean of 126.4. Estimated planetary A indices were 6, 9, 12, 12, 6, 8 and 17, with a mean of 10.
Amateur solar observer Tad Cook, K7RA,
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 k7ra@arrl.net.
| Previous: "It Seems to Us . . ." Nine Decades | Next: Surfin': Hams on Wheels |
