Last major update issued on February 25, 2010 at 05:20 UTC.
[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)
[Solar cycles 21-23 (last update October 4, 2007)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update October 4, 2007)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update October 4, 2007)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports (last update January 3, 2010)]
The geomagnetic field was quiet to unsettled on February 23. Solar wind speed ranged between 307 and 353 km/s.
Solar flux measured at 20h UTC on 2.8 GHz was 82.6. 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: 13000101 (planetary), 13011100 (Boulder).
The background x-ray flux is at the class A6 level.
At midnight there were 2 spotted regions on the visible solar disk.
Region 11050 was mostly unchanged and quiet.
New region 11051 rotated into view at the northeast limb on Feb.23 and
was numbered the next day by NOAA/SWPC.
February 22-24: No obvious Earth directed CMEs were observed in LASCO images.
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 poorly defined trans equatorial coronal hole (CH394) will be Earth facing on February 25-26.
Processed SOHO/EIT 195 image at 19:48 UTC on February 24. 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 fair. Propagation on long distance northeast-southwest paths is poor.
The geomagnetic field is expected to be mostly quiet on February 25-27. On February 28 and March 1 there's a chance of unsettled intervals due to effects from CH394.
| 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 | SWPC Classification |
Comment |
|---|---|---|---|---|---|---|---|
| 11048 | 2010.02.13 | N20W67 | plage | ||||
| 11049 | 2010.02.17 | 2 | S19W91 | 0010 | BXO | rotated out of view early in the day | |
| 11050 | 2010.02.23 | 5 | 9 | S19W27 | 0010 | BXO | classification was CSO at midnight, area 0030 |
| 11051 | 2010.02.24 | 3 | 2 | N17E66 | 0100 | CAO | formerly region S753 area was 0060 at midnight |
| Total spot count: | 10 | 11 | |||||
| SSN: | 40 | 31 | |||||
| Month | Average measured solar flux | International sunspot number (SIDC) | Smoothed sunspot number | Average ap (3) |
|---|---|---|---|---|
| 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) | |
| 2008.07 | 65.7 | 0.5 | 2.8 (-0.4) | |
| 2008.12 | 69.2 | 0.8 | 1.7 (-) sunspot minimum |
3.25 |
| 2009.01 | 69.8 | 1.3 | 1.8 (+0.1) | 3.70 |
| 2009.02 | 70.0 | 1.4 | 1.9 (+0.1) | 4.68 |
| 2009.03 | 69.2 | 0.7 | 2.0 (+0.1) | 4.85 |
| 2009.04 | 69.7 | 1.2 | 2.2 (+0.2) | 4.52 |
| 2009.05 | 70.5 | 2.9 | 2.3 (+0.1) | 4.75 |
| 2009.06 | 68.6 | 2.6 | 2.7 (+0.4) | 5.22 |
| 2009.07 | 68.2 | 3.5 | 3.6 (+0.9) | 5.49 / 4.55 |
| 2009.08 | 67.3 | 0.0 | (5.0 predicted, +1.4) | 5.70 / 4.89 |
| 2009.09 | 70.5 | 4.2 | (6.8 predicted, +1.8) | 3.88 / 3.61 |
| 2009.10 | 72.6 | 4.6 | (8.7 predicted, +1.9) | 3.66 / 3.56 |
| 2009.11 | 73.6 | 4.2 | (10.7 predicted, +2.0) | 2.45 / 2.63 |
| 2009.12 | 76.7 | 10.6 | (12.9 predicted, +2.2) | 1.41 / 1.92 |
| 2010.01 | 81.1 | 13.1 | (15.4 predicted, +2.5) | 2.93 / 3.07 |
| 2010.02 | 85.5 (1) | 27.2 (2) | (18.3 predicted, +2.9) | (4.51) |
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.
3) Running average based on the
daily SWPC ap indices. Values in red are based on
official NGDC ap indices.
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.