[HCARC] Space Weather

[Gary Johnson]

So what does this mean for Field Day??

The K7RA Solar Update
Tad Cook, K7RA, Seattle, reports: I thought it was too early in the decline of this solar cycle to start seeing days with no sunspots (ie, when the sunspot number is zero) but I was wrong. 

There were no sunspots on June 3-6. The last time there were four or more spot-less days was December 18-24, 2010 when there were no sunspots for an entire week. Last year, we saw no spot-less days, 2014 had just one, and there were none in 2012 or 2013. 

The average daily sunspot number dropped from 33 to 7.7 this week, and the average daily solar flux went from 87.4 to 80.7. Geomagnetic indicators were up slightly, with the planetary A index going from 8.9 to 11.6, and the mid-latitude A index from 9 to 9.4. 

Predicted solar flux for the near term is 80, 82, 85, and 90 on June 9-12; 95 on June 13-16; 90 on June 17-20; 85 on June 21-24; 80 on June 25-28; 78 on June 29-July 4; 82 on July 5-7; 85 on July 8-11, and 90 on July 12-17. 

Predicted planetary A index is 5, 8, 12, 16, and 12 on June 9-13; 8, 6, 8, 15, and 10 on June 14-18; 5 on June 19-22; 10, 12, and 8 on June 23-25; 10 on June 26-27; 5 on June 28-July 1; 25, 20; and 8 on July 2-4; 5 on July 5-8; 12 on July 9-10, and 8 on July 11-12. 

Sunspot numbers are somewhat subjective, based on a visual count of sunspot groups, the number of sunspots in those groups, and the total area covered by sunspots. Solar flux is an actual measure of one type of radiation reaching us from the sun -- radio energy with a wavelength of 10.7 centimeters, or 2.8 GHz. 

Sunspot numbers for June 2 through 8 were 27, 0, 0, 0, 0, 12, and 15, with a mean of 7.7. The 10.7 centimeter flux was 85.2, 83.2, 80, 79.1, 78.5, 78.5, and 80.1, with a mean of 87.4. Estimated planetary A indices were 4, 3, 4, 29, 26, 9, and 6, with a mean of 8.9. Estimated mid-latitude A indices were 5, 5, 5, 23, 21, 10, and 6 with a mean of 9.



Gary J

N5BAA