Last major update issued on February 26, 2008 at 05:05 UTC.
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The geomagnetic field was quiet on February 25. Solar wind speed ranged between 369 and 442 km/s.
Solar flux measured at 20h UTC on 2.8 GHz was 71.4. The planetary A index was 3 (STAR Ap - based on the mean of three hour interval ap indices: 3.0). Three hour interval K indices: 11120100 (planetary), 11221111 (Boulder).
The background x-ray flux is below the class A1 level.
At midnight there was 1 spotted region on the visible solar disk. The solar flare activity level was very low. No C class events were recorded during the day.
New region 10983 emerged in the southwest quadrant.
February 23-25: No partially or fully Earth directed CMEs were observed.
Coronal hole
history (since late October 2002)
Compare today's report to the situation one solar rotation ago:
28
days ago
27
days ago
26
days ago
A recurrent trans equatorial coronal hole (CH315) will likely rotate into an Earth facing position on February 24-28.
Processed STEREO 195 image at 00:15 UTC on February 25. The darkest areas on the solar disk are likely coronal holes.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over high and upper middle latitudes is good. Propagation on long distance northeast-southwest paths is poor.
The geomagnetic field is expected to be mostly quiet on February 26. Quiet to unsettled with occasional active intervals are possible on February 27 - March 2 due to effects from CH315.
Coronal holes (1) | Coronal mass ejections (2) | M and X class flares (3) |
1) Effects from a coronal hole could reach Earth
within the next 5 days. When the high speed stream has arrived the
color changes to green.
2) Effects from a CME are likely to be observed at Earth within 96
hours.
3) There is a possibility of either M or X class flares within the next
48 hours.
Green: 0-20% probability, Yellow: 20-60% probability, Red: 60-100% probability.
Compare to the previous day's image.
Data for all numbered solar regions according to the Solar Region Summary provided by NOAA/SWPC. Comments are my own, as is the STAR spot count (spots observed at or inside a few hours before midnight) and data for regions not numbered by SWPC or where SWPC has observed no spots. SWPC active region numbers in the table below and in the active region map above are the historic SWPC/USAF numbers.
Active region | Date numbered | SWPC spot count |
STAR spot count |
Location at midnight | Area | Classification | Comment |
---|---|---|---|---|---|---|---|
10983 | 2008.02.25 | 2 | 2 | S01W39 | 0020 | AXX | classification was CSO at midnight |
Total spot count: | 2 | 2 | |||||
SSN: | 12 | 12 |
Month | Average solar flux at Earth |
International sunspot number | Smoothed sunspot number |
---|---|---|---|
2000.04 | 184.2 | 125.5 | 120.8 cycle 23 sunspot max. |
2000.07 | 202.3 | 170.1 | 119.8 |
2001.12 | 235.1 | 132.2 | 114.6 (-0.9) |
2006.11 | 86.3 | 21.5 | 12.7 (-1.5) |
2006.12 | 84.5 | 13.6 | 12.1 (-0.6) |
2007.01 | 83.3 | 16.9 | 12.0 (-0.1) |
2007.02 | 77.7 | 10.6 | 11.6 (-0.4) |
2007.03 | 72.2 | 4.8 | 10.7 (-0.9) |
2007.04 | 72.4 | 3.7 | 9.8 (-0.9) |
2007.05 | 74.4 | 11.7 | 8.6 (-1.2) |
2007.06 | 73.7 | 12.0 | 7.6 (-1.0) |
2007.07 | 71.6 | 9.7 | 7.0 (-0.6) |
2007.08 | 69.1 | 5.7 | (6.1 predicted, -0.9) |
2007.09 | 67.1 | 1.9 | (6.0 predicted, -0.1) |
2007.10 | 67.4 | 0.9 | (6.5 predicted, +0.5) |
2007.11 | 69.6 | 1.7 | (6.9 predicted, +0.4) |
2007.12 | 78.5 | 10.1 | (7.1 predicted, +0.2) |
2008.01 | 74.3 | 3.4 | (7.6 predicted, +0.5) |
2008.02 | 71.2 (1) | 2.2 (2) | (8.6 predicted, +1.0) |
1) Running average based on the
daily 20:00 UTC observed solar flux
value at 2800 MHz.
2) Unofficial, accumulated value based on the Boulder (NOAA/SWPC) sunspot number. The official international sunspot number is typically
30-50% lower.
This report has been prepared by Jan Alvestad. It is based partly on my own observations and analysis, and partly on data from some of these solar data sources. All time references are to the UTC day. Comments and suggestions are always welcome.
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