Tad "Wild men who caught and sang the Sun in flight" Cook, K7RA, this week reports:
We saw a string of zero-sunspot days over the past couple of weeks, but this week saw a brief but significant sunspot that lasted only a couple of days. Sunspot 990 emerged as a tiny speck over April 14-15, but it was definitely a Solar Cycle 24 spot. Not only was the polarity of this region correct for the new Cycle, but it was far north above the Sun's equator, which is what we expect for a sunspot from an emerging solar cycle. The only previous Cycle 24 activity was close to the solar equator.
Sunspot numbers for April 10-16 were 0, 0, 0, 0, 11, 12 and 0 with a mean of 3.3. The 10.7 cm flux was 67.9, 67.1, 68.2, 69.3, 68.5, 69.2 and 69.5 with a mean of 68.5. Estimated planetary A indices were 8, 4, 11, 7, 2, 5 and 15 with a mean of 7.4. Estimated mid-latitude A indices were 6, 3, 8, 6, 2, 3 and 9, with a mean of 5.3.
Geophysical Institute Prague predicts quiet conditions April 18, quiet to unsettled April 19, quiet April 20, quiet to unsettled April 21, active April 22-23 and unsettled to active April 24.
For more information concerning radio propagation, visit the ARRL Technical Information Service Propagation page <http://www.arrl.org/tis/info/propagation.html>. To read this week's Solar Report in its entirety, check out the W1AW Propagation Bulletin page <http://www.arrl.org/w1aw/prop/>.
| Notes | This solar update is brought to you courtesy of the American Radio Relay League's ARRL Letter. |
