The average daily sunspot numbers sank nearly 50 points this week to 94.3, while the average daily solar flux was down more than 16 points to 117.8. The geomagnetic indices were quite high, due to a solar wind storm. Sunspot numbers for May 23-29 were 117, 99, 107, 92, 87, 75 and 83, with a mean of 94.3. The 10.7 centimeter flux was 134.5, 127.3, 121.3, 120, 110.1, 104.8 and 106.9, with a mean …
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Solar activity made a healthy jump over the past week, with the average daily sunspot numbers up more than 30 points to 120.9, while the average daily solar flux increased more than 27 points to 136.5. The most active day for geomagnetic indices was May 1, when the planetary A index reached 21 and the high-latitude College A index (measured near Fairbanks, Alaska) was a whopping 57. That number…
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Solar indicators were mixed this week, with the average daily sunspot number down 8.4 points to 84.9, while the average daily solar flux rose 5.9 points to 118.5. Geomagnetic indices were much quieter, with the average planetary A index down 4.7 points to 4.4 and the average mid-latitude A index down 5 points to 3.9. Sunspot numbers for March 7-13 were 80, 59, 63, 89, 105, 95 and 103, with a me…
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This past week, there was a decline in the solar and geomagnetic indices: The average daily sunspot number dropped nearly 21 points to 57.7, while the average daily solar flux softened by 4.7 points to 100.9 and the average daily planetary A index declined 6.4 points to 5.1. This isn’t much of a change, but geomagnetic activity was low already, and this is even lower.
Sunspot numbers for Februar…
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There was a modest rise in the average daily sunspot numbers over the past seven days, rising 27 points to 78.3, while the average daily solar flux was up marginally, only 1.6 points to 105.6. The geomagnetic indices also went up, with the planetary A index rising from 5.6 to 6.4, and the middle latitude A index rising from 5.1 to 6. There was a more substantial rise in both the solar flux and …
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The average daily sunspot numbers this past week dropped nearly 73 points to 56.4, while the average daily solar flux declined nearly 47 points to 110.7. The average geomagnetic indices were up about 50 percent, but it was still very quiet. The difference was mostly due to events on January 17 when the planetary A index was 13 — higher than in recent weeks, but still moderate. The cause of the…
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The average daily sunspot numbers fell 13.5 points this week, from 61.1 to 47.6, while the average daily solar flux was about the same this week as last, rising 1.1 points to 102.7. Geomagnetic indices were even quieter this week than last. Sunspot numbers for December 6-12 were 49, 23, 35, 40, 49, 55 and 82, with a mean of 47.6. The 10.7 centimeter flux was 97.4, 97.1, 101.1, 103.7, 104, 103.7…
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A coronal mass ejection (CME) hit the Earth on September 30, triggering a jump in geomagnetic indices. The planetary A index on October 1 was 31, and the K index jumped to 7, making aurora visible across the northern tier of the United States. The northern latitude college A index was 23 (near Fairbanks, Alaska), about the same as the mid-latitude index — which was 21 — in Fredericksburg, Vir…
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In last week’s Solar Update, we reported a blast of energy from a solar flare headed our way, predicted to arrive on Saturday, July 14. The CME hit at 1800 UTC, and it had a huge effect on propagation and geomagnetic indices. The next day, the planetary A index was 60, the mid latitude A index was 39 and the high latitude college A index was 88. Conditions haven’t been that upset since March 9,…
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