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 Previous: Last Year's Youngest General Now This Year's Youngest Extra |  Next: ARRL In Action: What Have We Been Up To Lately? |
SEATTLE, WA, Jan 30, 2004--There are no sunspots! The visible solar disk is blank. This prompts e-mail inquiring if it's normal to see a spotless sun at this point in the solar cycle. Yes, it is normal, because there are big variations from day to day.
In order to generalize and see the larger trends, we need to calculate a very smooth running average, where readings from many days or months are averaged together. An example of a smooth chart using running or moving averages of many data points are on the NOAA National Geophysical Data Center (NGDC) Web site or on the DX Listeners' Club, Norway site. The NGDC includes an explanation of how a smoothed sunspot number is calculated based on 12 months of averaged data. There is also a very interesting graphic representation of the difference between a running average based on 12 months and the averages for each individual month over the same period on the Sunspot Trends Web site.
For the 12 months of data there is still a point on the graph for each day, but that point represents all the data from 6 months before and 6 months after, averaged together. The point for the next day is the same, but drops one day off at the back end and averages in another day's data from 6 months in the future. This is why reports showing the current smoothed sunspot number always must be at least 6 months in the past.
In the Sunspot Trends Web site chart, those tiny colored diamonds each represent a month of averaged data, just like those averages presented frequently in this bulletin. An example of those monthly averages is in the K7RA Solar Update for December 1, 2003.
Jeffrey Philpott, N6QYS, asks if the solar cycle is near bottom, and how long will it be until conditions improve? If we look at the end of a recent (January 6) issue of the NOAA Preliminary Report and Forecast of Solar Geophysical Data, it shows a projection of future sunspot and solar flux values for nearly the next four years--until December 2007. This is a rough guess based on previous solar cycles. We can see from both spreadsheets that the predicted bottom of the cycle is expected to occur some time around the end of 2006. That said, given our discussion regarding long moving averages, we really won't know when the bottom occurs until some time after we've passed it.
We could assume that as we examine projections for rising values during the next cycle, an estimate could be made for when conditions should improve past the current level by looking for a value that matches current conditions. Unfortunately, the data don't go that far into the future. The best we can say is that a year from now conditions should be worse, and that the projected number for January 2005 doesn't rise back to that same level until December 2007.
Because January 2005 is a year from now, could we assume that current conditions will worsen and not be at this level again until December 2008? We can't really do that, because solar cycles tend to rise faster than they decline. A wild guess could be that some time in 2008 conditions will be back to where they are now. We can all make notes in our PDAs to check back to this bulletin in 2008 to see if we were far off base. I've done this, and four years from now should be quite surprised to see this note from the past.
Conditions will likely improve somewhat over the next week. The weekly average of daily sunspots for this week was half what it was the week before. Average daily solar flux declined over 21 points. Projected solar flux for Friday through Monday, January 30 through February 2, is 90, 90, 100 and 100. Solar flux is expected to peak for the short term around February 8.
Geomagnetic conditions may be rough over the next week, unsettled to active. Predicted planetary A index for January 30 through February 5 is 15, 20, 20, 25, 25, 15 and 10.
The UBA DX SSB Contest is this weekend (the CW event will be in February). The goal of this competition is to work as many European stations on 80, 40, 20, 15 and 10 meters--and especially Belgian stations. Working Belgium is worth three times the points counted for contacts with other European countries. We won't hazard to guess when 80 and 40 meters should be good for working Belgium or the rest of Europe, but here are some projections for bands higher than 40 meters.
From Seattle, best conditions look to be on 20 meters after local sunrise, 1630-1900 UTC, and a weak possibility on 15 meters around 1630-1700 UTC. There is another possible opening on 20, although not as strong, after local sunrise at the European end around 0830-1000 UTC.
From Southern California, conditions look best on 20 meters again after local sunrise, from 1530-1900 UTC, and around 1700 UTC on 15.
From North Texas, conditions look best after local sunrise from 1400-2030 UTC on 20 meters, 1530-1700 UTC on 15 and possibly on 10 around 1630 UTC.
From Utah, check 20 meters around 1530-2000 UTC.
From Nebraska and Kansas, the center of the contiguous 48 states, check 20 meters around 1500-1930 UTC.
From Chicago, check 20 meters after sunrise from 1400-2030 UTC and 15 meters 1630-1830 UTC.
From Ohio, check 20 meters after sunrise from 1330-2030 UTC and 15 meters 1600-1800 UTC.
Boston should have an excellent path around 1230-2000 UTC on 20 meters, and 1500-1730 UTC on 15 meters.
Centered around the New York City area, the projection looks like Boston's, except there is a greater chance of a 10-meter opening around 1630-1700 UTC. Philadelphia's prediction looks just like New York City's.
Atlanta looks good from 1300-1930 UTC on 20 meters and 1500-1630 UTC on 15 meters.
South Florida should be good on 20 meters from 1230-2000 UTC, 15 meters 1400-1700 UTC, and possibly 10 meters around 1430-1600 UTC.
Montreal, Quebec, looks good on 20 meters from 1230-2030 UTC and 15 meters around 1530-1730 UTC.
Winnipeg, Manitoba, looks good on 20 meters right at sunrise, from 1400-2000 UTC. This is a polar path, so it could be especially affected by geomagnetic activity.
Edmonton, Alberta, is also a polar path, and 20-meter openings may occur 1630-1930 UTC.
South Central Alaska is also a polar path, and doesn't look very good at all for 20 meters to Europe. There are only about seven hours of daylight at the Alaska end. The worst times look to be 0400-0600 UTC on 20 meters.
Hawaii is so far from Europe that the openings have nothing to do with sunrise at the KH6 end, but look good on 20 meters after sunrise at the Belgium end, 0800-1330 UTC.
From Japan, the openings look long, 0630-1800 UTC on 20 meters, 0830-0900 UTC on 15 meters, and possibly 10 meters around 0800 UTC.
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 January 22 through 28 were 76, 62, 47, 48, 38, 0 and 0, with a mean of 38.7. The 10.7 cm flux was 121.8, 115.2, 107.5, 102.3, 98, 93.7 and 88.5, with a mean of 103.9. Estimated planetary A indices were 62, 38, 15, 33, 17, 16 and 19, with a mean of 28.6.
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.
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