Last major update issued on February 11, 2004 at 04:25 UTC.
[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update February 2, 2004)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update February 2, 2004)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update February
2, 2004)]
[Historical solar and geomagnetic data charts 1954-2003 (last update January 16,
2004)]
[Archived reports (last update February 9, 2004)]
The geomagnetic field was quiet to unsettled on February10. Solar wind speed ranged between 348 and 419 km/sec.
Solar flux measured at 20h UTC on 2.8 GHz was 116.5. The planetary A
index was 9 (STAR Ap - based on the mean of three hour interval ap indices: 9.9).
Three hour interval K indices: 22233321 (planetary), 22232212 (Boulder).
The background x-ray flux is at the class B2 level.
At midnight there were 6 spotted regions on the visible disk. Solar flare activity was very low. No C class events was recorded during the day.
Region 10549 decayed and was spotless in the evening, however, a small spot became visible by midnight.
Region 10551 decayed quickly losing more than half of the penumbral area over the day.
Region 10554 added slightly to the penumbral area. Magnetically the region simplified further and there is no longer any
polarity intermixing.
Region 10555 was quiet and stable.
Spotted regions not numbered by NOAA/SEC:
[S349] This region emerged in the northwest quadrant on February 9. Location at midnight: N07W33.
[S350] A new region emerged in the northeast quadrant on February 9 and developed slowly on February 10. Location at midnight:
N16E35.
February 8-10: No partly or fully earth directed CMEs observed.
Coronal hole history (since late October 2002)
Compare today's report with the situation one solar rotation ago: 28
days ago 27 days ago 26 days ago
A recurrent trans equatorial coronal hole (CH80) will rotate into a geoeffective position on February 9-12.
Processed SOHO/EIT 284 image at 19:06 UTC on February 10. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to unsettled February 11 and unsettled to active on February 12-15 due to a high speed stream from coronal hole CH80. A few minor storm intervals are possible on February 13.
Long distance low and medium frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is poor. Propagation along long distance north-south paths is poor. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant stations tonight: Radio Cristal del Uruguay and Radio Vibración (Venezuela). On other frequencies several stations from Newfoundland, Nova Scotia and the northeastern part of the US were noted with fairly weak signals on the northwesterly EWE].
| 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) Material from a CME is likely to impact 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/SEC. 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 SEC or where SEC has observed no spots. SEC active region numbers in the table below and in the active region map above are the historic SEC/USAF numbers.
| Active region | Date numbered | SEC spot count |
STAR spot count |
Location at midnight | Area | Classification | Comment |
|---|---|---|---|---|---|---|---|
| 10549 | 2004.01.31 | 3 | 1 | N13W62 | 0030 | BXO |
classification was AXX at midnight, area 0000 |
| 10551 | 2004.02.02 | 20 | 12 | S08W41 | 0210 | ESO |
beta-gamma classification was DAO at midnight, area 0130 |
| 10552 | 2004.02.02 | S08W83 | plage | ||||
| 10553 | 2004.02.05 | S04W64 | plage | ||||
| 10554 | 2004.02.07 | 14 | 13 | S10E38 | 0250 | DSC | |
| 10555 | 2004.02.09 | 1 | 1 | S14E58 | 0030 | HSX | |
| S349 | emerged on 2004.02.09 |
2 | N07W33 | 0000 | BXO | ||
| S350 | emerged on 2004.02.09 |
3 | N16E35 | 0030 | CSO | ||
| Total spot count: | 38 | 32 | |||||
| SSN: | 78 | 92 | |||||
| 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) |
| 2003.01 | 144.0 | 79.7 | 80.8 (-1.2) |
| 2003.02 | 124.5 | 46.0 | 78.3 (-2.5) |
| 2003.03 | 131.4 | 61.1 | 74.0 (-4.3) |
| 2003.04 | 126.4 | 60.0 | 70.1 (-3.9) |
| 2003.05 | 115.7 | 55.2 | 67.6 (-2.5) |
| 2003.06 | 129.3 | 77.4 | 65.0 (-2.6) |
| 2003.07 | 127.7 | 83.3 | 61.8 (-3.2) |
| 2003.08 | 122.1 | 72.7 | (59.4 predicted, -2.4) |
| 2003.09 | 112.2 | 48.7 | (57.6 predicted, -1.8) |
| 2003.10 | 151.7 | 65.6 | (54.9 predicted, -2.7) |
| 2003.11 | 140.8 | 67.2 | (52.2 predicted, -2.7) |
| 2003.12 | 114.9 | 47.0 | (49.6 predicted, -2.6) |
| 2004.01 | 114.1 | 37.2 | (45.4 predicted, -4.2) |
| 2004.02 | 107.3 (1) | 30.4 (2) | (40.8 predicted, -4.6) |
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/SEC) sunspot number. The official international sunspot number is typically
30-50% less.
This report has been prepared by Jan Alvestad. It is based partly on my own observations and analysis, and partly on data from sources noted in solar links. All time references are to the UTC day. Comments and suggestions are always welcome.
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